BORON NITRIDE

Boron Nitride = BN

CAS Number: 10043-11-5 
IUPAC Name: Boron nitride
EC Number: 233-136-6
Molecular Weight: 24.82 g/mol    
Molecular Formula: Boron nitride

Description: 
The empirical formula of boron nitride (Boron nitride) is deceptive. 
Boron nitride is not at all like other diatomic molecules such as carbon monoxide (CO) and hydrogen chloride (HCl). 
Rather, boron nitride has much in common with carbon, whose representation as the monatomic C is also misleading.
Boron nitride, like carbon, has multiple structural forms. 
Boron nitride’s most stable structure is isoelectronic with graphite and has the same hexagonal structure with similar softness and lubricant properties. 
hBoron nitride can also be produced in graphene-like sheets that can be formed into nanotubes.
In contrast, cubic boron nitride (cBoron nitride) is isoelectronic with diamond. 
Boron nitride is not quite as hard, but it is more thermally and chemically stable. 
Boron nitride is also much easier to make. 
Unlike diamond, boron nitride is insoluble in metals at high temperatures, making it a useful abrasive and oxidation-resistant metal coating. 
There is also an amorphous form (aBoron nitride), equivalent to amorphous carbon (see below).
Boron nitride is primarily a synthetic material, although a naturally occurring deposit has been reported. 
Attempts to make pure Boron nitride date to the early 20th century, but commercially acceptable forms have been produced only in the past 70 years. 
In a 1958 patent to the Carborundum Company (Lewiston, NY), Kenneth M. Taylor prepared molded shapes of Boron nitride by heating boric acid (H3BO3) with a metal salt of an oxyacid in the presence of ammonia to form a Boron nitride mix.
Today, similar methods are in use that begin with boric trioxide (B2O3) or H3BO3 and use ammonia or urea as the nitrogen source. 
All synthetic methods produce a somewhat impure aBoron nitride, which is purified and converted to hBoron nitride by heating at temperatures higher than used in the synthesis. 
Similarly, to the preparation of synthetic diamond, hBoron nitride is converted to cBoron nitride under high pressure and temperature.
The substance is composed of hexagonal structures that appear in crystalline form and is usually compared to graphite. 
Boron nitride may come in the form of a flat lattice or a cubic structure, both of which retain the chemical and heat resistance that boron nitride is known for.
Heat and chemical resistance: The compound has a melting point of 2,973°C and a thermal expansion coefficient significantly above that of diamond. 
Boron nitride's hexagonal form resists decomposition even when exposed to 1000°C in ambient air. Boron nitride doesn’t dissolve in common acids.
Thermal conductivity: At 1700 to 2000 W/mK, boron nitride has a thermal conductivity that is comparable with that of graphene, a similarly hexagon-latticed compound but made up of carbon atoms.
Lubricating property: Boron nitride has the ability to boost the coefficient of friction of lubricating oil, while reducing the potential for wear.
Density: Depending on its form, its density ranges from 2.1 to 3.5 g/cm3.
Boron nitride is an advanced synthetic ceramic material available in solid and powder form. 
Boron nitride's unique properties – from high heat capacity and outstanding thermal conductivity to easy machinability, lubricity, low dielectric constant and superior dielectric strength.
In boron nitride's solid form, boron nitride is often referred to as “white graphite” because it has a microstructure similar to that of graphite. 
However, unlike graphite, boron nitride is an excellent electrical insulator that has a higher oxidation temperature. 
Boron nitride offers high thermal conductivity and good thermal shock resistance and can be easily machined to close tolerances in virtually any shape. 
After machining, boron nitride is ready for use without additional heat treating or firing operations.
Boron nitride is a thermally and chemically resistant refractory compound of boron and nitrogen with the chemical formula Boron nitride. 
Boron nitride exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. 
The hexagonal form corresponding to graphite is the most stable and soft among Boron nitride polymorphs, and is therefore used as a lubricant and an additive to cosmetic products. 
The cubic (zincblende aka sphalerite structure) variety analogous to diamond is called c-Boron nitride; it is softer than diamond, but its thermal and chemical stability is superior. 
The rare wurtzite boron nitride modification is similar to lonsdaleite but slightly softer than the cubic form.
Because of excellent thermal and chemical stability, boron nitride ceramics are used in high-temperature equipment. 
Boron nitride has potential use in nanotechnology.
The partly ionic structure of boron nitride layers in h-Boron nitride reduces covalency and electrical conductivity, whereas the interlayer interaction increases resulting in higher hardness of h-Boron nitride relative to graphite. 
The reduced electron-delocalization in hexagonal-boron nitride is also indicated by its absence of color and a large band gap. 
Very different bonding – strong covalent within the basal planes (planes where boron and nitrogen atoms are covalently bonded) and weak between them – causes high anisotropy of most properties of h-Boron nitride.
For example, the hardness, electrical and thermal conductivity are much higher within the planes than perpendicular to them. 
On the contrary, the properties of c-Boron nitride and w-Boron nitride are more homogeneous and isotropic.
Those materials are extremely hard, with the hardness of bulk c-Boron nitride being slightly smaller and w-Boron nitride even higher than that of diamond.
Polycrystalline c-Boron nitride with grain sizes on the order of 10 nm is also reported to have Vickers hardness comparable or higher than diamond.
Because of much better stability to heat and transition metals, c-Boron nitride surpasses diamond in mechanical applications, such as machining steel.
The thermal conductivity of Boron nitride is among the highest of all electric insulators.
Boron nitride can be doped p-type with beryllium and n-type with boron, sulfur, silicon or if co-doped with carbon and nitrogen.
Both hexagonal and cubic Boron nitride are wide-gap semiconductors with a band-gap energy corresponding to the UV region. If voltage is applied to h-Boron nitride or c-Boron nitride.
Then it emits UV light in the range 215–250 nm and therefore can potentially be used as light-emitting diodes (LEDs) or lasers.
Little is known on melting behavior of boron nitride. 
Boron nitride sublimates at 2973 °C at normal pressure releasing nitrogen gas and boron, but melts at elevated pressure.
Boron nitride (Boron nitride) exists in several polymorphic forms such as a-Boron nitride, h-Boron nitride, t-Boron nitride, r-Boron nitride, m-Boron nitride, o-Boron nitride, w-Boron nitride, and c-Boron nitride phases. 
Among them, c-Boron nitride and h-Boron nitride are the most common ceramic powders used in composites to ensure enhanced material properties. 
Cubic boron nitride (c-Boron nitride) has exceptional properties such as hardness, strength than relating with other ceramics so that are most commonly used as abrasives and in cutting tool applications. c-Boron nitride possesses the second highest thermal conductivity after diamond and relatively low dielectric constant. 
Hence pioneer preliminary research in AMCs proven substitute composites than virgin AA 6061 traditionally used for fins in heat sinks. 
Moreover, poly-crystalline c-Boron nitride (PCBoron nitride) tools are most suitable for various machining tasks due to their unmatchable mechanical properties. 
h-Boron nitride also finds its own unique applications where polymer composites for high temperature applications and sp3 bonding in extreme temperature and compression conditions.
Boron nitride exists in multiple forms that differ in the arrangement of the boron and nitrogen atoms, giving rise to varying bulk properties of the material.

Properties of Boron Nitride
Characteristics of boron nitride (boron nitride) Include:
-excellent lubricating properties
-hot pressed Boron Nitride (HPBoron nitride) can be machined using traditional metal turning techniques
-if used in an inert environment the surface of HPBoron nitride will not be wetted by molten metals, glasses and salts and hence has a high resistance to chemical attack
-good chemical inertness
-high volume resistivity
-high dielectric breakdown strength
Hexagonal and cubic (and probably w-Boron nitride) Boron nitride show remarkable chemical and thermal stabilities. 
For example, h-Boron nitride is stable to decomposition at temperatures up to 1000 °C in air, 1400 °C in vacuum, and 2800 °C in an inert atmosphere. 
The reactivity of h-Boron nitride and c-Boron nitride is relatively similar, and the data for c-Boron nitride are summarized in the table below.
Thermal stability of c-Boron nitride can be summarized as follows:
In air or oxygen: B2O3 protective layer prevents further oxidation to ~1300 °C; no conversion to hexagonal form at 1400 °C.
In nitrogen: some conversion to h-Boron nitride at 1525 °C after 12 h.
In vacuum (10−5 Pa): conversion to h-Boron nitride at 1550–1600 °
Boron nitride is insoluble in the usual acids, but is soluble in alkaline molten salts and nitrides, such as LiOH, KOH, NaOH-Na2CO3, NaNO3, Li3N, Mg3N2, Sr3N2, Ba3N2 or Li3Boron nitride2, which are therefore used to etch Boron nitride.
The theoretical thermal conductivity of hexagonal boron nitride nanoribbons (Boron nitrideNRs) can approach 1700–2000 W/(m·K), which has the same order of magnitude as the experimental measured value for graphene.
Boron nitride can be comparable to the theoretical calculations for graphene nanoribbons.
Moreover, the thermal transport in the Boron nitrideNRs is anisotropic. The thermal conductivity of zigzag-edged Boron nitrideNRs is about 20% larger than that of armchair-edged nanoribbons at room temperature.
In 2009, a naturally occurring boron nitride mineral in the cubic form (c-Boron nitride) was reported in Tibet, and the name qingsongite proposed. 
The substance was found in dispersed micron-sized inclusions in chromium-rich rocks. 
In 2013, the International Mineralogical Association affirmed the mineral and the name.
Preparation and reactivity of hexagonal Boron nitride:
Boron nitride is produced synthetically. 
Hexagonal boron nitride is obtained by the reacting boron trioxide (B2O3) or boric acid (H3BO3) with ammonia (NH3) or urea (CO(NH2)2) in a nitrogen atmosphere:
B2O3 + 2 NH3 → 2 Boron nitride + 3 H2O (T = 900 °C)
B(OH)3 + NH3 → Boron nitride + 3 H2O (T = 900 °C)
B2O3 + CO(NH2)2 → 2 Boron nitride + CO2 + 2 H2O (T > 1000 °C)
B2O3 + 3 CaB6 + 10 N2 → 20 Boron nitride + 3 CaO (T > 1500 °C)
The resulting disordered (amorphous) boron nitride contains 92–95% Boron nitride and 5–8% B2O3. 
The remaining B2O3 can be evaporated in a second step at temperatures > 1500 °C in order to achieve Boron nitride concentration >98%.
Such annealing also crystallizes Boron nitride, the size of the crystallites increasing with the annealing temperature.
h-Boron nitride parts can be fabricated inexpensively by hot-pressing with subsequent machining. 
The parts are made from boron nitride powders adding boron oxide for better compressibility. 
Thin films of boron nitride can be obtained by chemical vapor deposition from boron trichloride and nitrogen precursors.
Combustion of boron powder in nitrogen plasma at 5500 °C yields ultrafine boron nitride used for lubricants and toners.
Boron nitride reacts with iodine fluoride in trichlorofluoromethane at −30 °C to produce an extremely sensitive contact explosive, NI3, in low yield.
Boron nitride reacts with nitrides of lithium, alkaline earth metals and lanthanides to form nitridoborate compounds:
Li3N + Boron nitride → Li3Boron nitride2
Similar to graphite, various molecules, such as NH3 or alkali metals, can be intercalated into hexagonal boron nitride, that is inserted between its layers. 
Both experiment and theory suggest the intercalation is much more difficult for Boron nitride than for graphite.

Types of Boron Nitride:
Hexagonal: This form of boron nitride has the highest number of applications, because of its high lubricating property, electrical conductivity, and thermal stability.
Cubic: The cubic form of Boron nitride possesses significantly high electrical resistivity and thermal conductivity like diamond. 
C-Boron nitride doesn’t dissolve in steel components, thereby making it a good abrasive material.
Amorphous: The non-crystalline form of boron nitride is comparable to amorphous carbon in terms of structure and properties.
Atomically thin: Despite its ultra-thin property, this Boron nitride polymorph is characterised by high thermal conductivity, increased surface adsorption, and good dielectric properties.
Nanotube: As one of the rising developments in recent times, nanotube technology has been given a boost with the use of boron nitride. 
This rolled-up form of hexagonal Boron nitride is similar to carbon nanotubes in terms of structure. 
However, Boron nitride nanotubes have higher electrical insulation as well as better resistance to heat and chemical reactions.
Synthesis of c-Boron nitride uses same methods as that of diamond: Cubic boron nitride is produced by treating hexagonal boron nitride at high pressure and temperature, much as synthetic diamond is produced from graphite. Direct conversion of hexagonal boron nitride to the cubic form has been observed at pressures between 5 and 18 GPa and temperatures between 1730 and 3230 °C.
That is similar parameters as for direct graphite-diamond conversion.
The addition of a small amount of boron oxide can lower the required pressure to 4–7 GPa and temperature to 1500 °C. 
To further reduce the conversion pressures and temperatures, a catalyst is added, such as lithium, potassium, or magnesium, their nitrides, their fluoronitrides, water with ammonium compounds, or hydrazine.
Other industrial synthesis methods, again borrowed from diamond growth, use crystal growth in a temperature gradient, or explosive shock wave. 
The shock wave method is used to produce material called heterodiamond, a superhard compound of boron, carbon, and nitrogen.
Low-pressure deposition of thin films of cubic boron nitride is possible. 
As in diamond growth, the major problem is to suppress the growth of hexagonal phases (h-Boron nitride or graphite, respectively). 
Whereas in diamond growth this is achieved by adding hydrogen gas, boron trifluoride is used for c-Boron nitride. 
Ion beam deposition, plasma-enhanced chemical vapor deposition, pulsed laser deposition, reactive sputtering, and other physical vapor deposition methods are used as well.
Wurtzite Boron nitride can be obtained via static high-pressure or dynamic shock methods.
The limits of its stability are not well defined. Both c-Boron nitride and w-Boron nitride are formed by compressing h-Boron nitride, but formation of w-Boron nitride occurs at much lower temperatures close to 1700 °C.
The amorphous form of boron nitride (a-Boron nitride) is non-crystalline, lacking any long-distance regularity in the arrangement of its atoms. 
Boron nitride is analogous to amorphous carbon.
All other forms of boron nitride are crystalline.
The most stable crystalline form is the hexagonal one, also called h-Boron nitride, α-Boron nitride, g-Boron nitride, and graphitic boron nitride. 
Hexagonal boron nitride (point group = D6h; space group = P63/mmc) has a layered structure similar to graphite. 
Within each layer, boron and nitrogen atoms are bound by strong covalent bonds, whereas the layers are held together by weak van der Waals forces. 
The interlayer "registry" of these sheets differs, however, from the pattern seen for graphite, because the atoms are eclipsed, with boron atoms lying over and above nitrogen atoms. 
This registry reflects the local polarity of the B–N bonds, as well as interlayer N-donor/B-acceptor characteristics. 
Likewise, many metastable forms consisting of differently stacked polytypes exist. 
Therefore, h-Boron nitride and graphite are very close neighbors, and the material can accommodate carbon as a substituent element to form Boron nitrideCs. 
BC6N hybrids have been synthesized, where carbon substitutes for some B and N atoms.
Hexagonal boron nitride (h-Boron nitride) is an analogue of graphite called “white graphene.” 
In the structure of h-Boron nitride, B and N atoms substitute C atoms. The boron and nitrogen atoms are linked via strong B-N covalent bonds and form interlocking hexagonal rings. 
h-Boron nitride is used in different areas due to its interesting physical and chemical properties, e.g., in electronics as an insulator and in ceramics, resins, plastics, and paints. 
Therefore, boron nitride (Boron nitride) is also a popular inorganic compound in cosmetic industry (the highest Boron nitride concentration up to 25% can be found in eye shadow formulation). 
h-Boron nitride is also widely used in dental cement production (for dental and orthodontic applications). 
h-Boron nitride seems to be suitable for biomedical applications; therefore, the cytotoxicity in vitro and in vivo observations of h-Boron nitride nanoplates and novel few-layered h-Boron nitride-based nanocomposites are still needed. 
The short-time studies confirm their low cytotoxicity and suggest that Boron nitride can be used as a novel drug delivery system; however, medical application needs additional verification in long-term studies.
Hexagonal boron nitride (HBoron nitride) is a solid lubricant relating to the class of Inorganic lubricants with lamellar structure, which also includes molybdenum disulphide, graphite and some other sulphides, selenides and tellurides (chalcogenides) of molybdenum, tungsten, niobium, tantalum and titanium.
The crystal lattice of hexagonal boron nitride consists of hexagonal rings forming thin parallel planes. Atoms of boron (B) and nitrogen (N) are covalently bonded to other atoms in the plane with the angle 120 ° between two bonds (each boron atom is bonded to three nitrogen atoms and each nitrogen atom is bonded to three boron atoms).
The planes are bonded to each other by weak Van der Waals forces.
Cubic boron nitride has a crystal structure analogous to that of diamond. 
Consistent with diamond being less stable than graphite, the cubic form is less stable than the hexagonal form, but the conversion rate between the two is negligible at room temperature, as it is for diamond. 
The cubic form has the sphalerite crystal structure, the same as that of diamond (with ordered B and N atoms), and is also called β-Boron nitride or c-Boron nitride.
The wurtzite form of boron nitride (w-Boron nitride; point group = C6v; space group = P63mc) has the same structure as lonsdaleite, a rare hexagonal polymorph of carbon.
As in the cubic form, the boron and nitrogen atoms are grouped into tetrahedra.
In the wurtzite form, the boron and nitrogen atoms are grouped into 6-membered rings. 
In the cubic form all rings are in the chair configuration, whereas in w-Boron nitride the rings between 'layers' are in boat configuration. 
Earlier optimistic reports predicted that the wurtzite form was very strong, and was estimated by a simulation as potentially having a strength 18% stronger than that of diamond. 
Since only small amounts of the mineral exist in nature, this has not yet been experimentally verified.
Recent studies measured w-Boron nitride hardness at 46 GPa, slightly harder than commercial borides but softer than the cubic form of boron nitrid.
Atomically thin boron nitride: Hexagonal boron nitride can be exfoliated to mono or few atomic layer sheets. 
Due to hexagonal boron nitride's analogous structure to that of graphene, atomically thin boron nitride is sometimes called “white graphene”.
Mechanical properties: Atomically thin boron nitride is one of the strongest electrically insulating materials. 
Monolayer boron nitride has an average Young's modulus of 0.865TPa and fracture strength of 70.5GPa.
In contrast to graphene, whose strength decreases dramatically with increased thickness, few-layer boron nitride sheets have a strength similar to that of monolayer boron nitride.
Thermal conductivity: Atomically thin boron nitride has one of the highest thermal conductivity coefficients (751 W/mK at room temperature) among semiconductors and electrical insulators.
The thermal conductivity of atomically thin boron nitride increases with reduced thickness due to less intra-layer coupling.
The air stability of graphene shows a clear thickness dependence: monolayer graphene is reactive to oxygen at 250 °C, strongly doped at 300 °C, and etched at 450 °C.
In contrast, bulk graphite is not oxidized until 800 °C.
Atomically thin boron nitride has much better oxidation resistance than graphene. 
Monolayer boron nitride is not oxidized till 700 °C and can sustain up to 850 °C in air; bilayer and trilayer boron nitride nanosheets have slightly higher oxidation starting temperatures.
The excellent thermal stability, high impermeability to gas and liquid,electrical insulation make atomically thin boron nitride potential coating materials for preventing surface oxidation and corrosion of metals.
Better surface adsorption: Atomically thin boron nitride has been found to have better surface adsorption capabilities than bulk hexagonal boron nitride.
Atomically thin boron nitride as an adsorbent experiences conformational changes upon surface adsorption of molecules, increasing adsorption energy and efficiency. 
Boron nitride nanosheets can increase the Raman sensitivity by up to two orders due to:
The synergic effect of the atomic thickness
high flexibility
stronger surface adsorption capability
electrical insulation, impermeability
high thermal and chemical stability 
In the meantime attain long-term stability and extraordinary reusability not achievable by other materials.
Dielectric properties: Atomically thin hexagonal boron nitride is an excellent dielectric substrate for graphene, molybdenum disulfide (MoS2), and many other 2D material-based electronic and photonic devices. 
As shown by electric force microscopy (EFM) studies, the electric field screening in atomically thin boron nitride shows a weak dependence on thickness.
Raman spectroscopy has been a useful tool to study a variety of 2D materials, and the Raman signature of high-quality atomically thin boron nitride was first reported by Gorbachev et al. in 2011.and Li et al. However, the two reported Raman results of monolayer boron nitride did not agree with each other. 
Cai et al., therefore, conducted systematic experimental and theoretical studies to reveal the intrinsic Raman spectrum of atomically thin boron nitride.
Atomically thin boron nitride without interaction with a substrate has a G band frequency similar to that of bulk hexagonal boron nitride.
But strain induced by the substrate can cause Raman shifts. Nevertheless, the Raman intensity of G band of atomically thin boron nitride can be used to estimate layer thickness and sample quality.
Boron nitride nanomesh is a nanostructured two-dimensional material. 
Boron nitride nanomesh consists of a single Boron nitride layer, which forms by self-assembly a highly regular mesh after high-temperature exposure of a clean rhodium[68] or ruthenium surface to borazine under ultra-high vacuum. 
The nanomesh looks like an assembly of hexagonal pores. 
The distance between two pore centers is 3.2 nm and the pore diameter is ~2 nm. 
Other terms for this material are boronitrene or white graphene.
The boron nitride nanomesh is not only stable to decomposition under vacuum, air and some liquids,[72][73] but also up to temperatures of 800 °C.
In addition, it shows the extraordinary ability to trap molecules and metallic clusters which have similar sizes to the nanomesh pores, forming a well-ordered array. 
These characteristics promise interesting applications of the nanomesh in areas like catalysis, surface functionalisation, spintronics, quantum computing and data storage media like hard drives.
Boron nitride tubules were first made in 1989 by Shore and Dolan This work was patented in 1989 and published in 1989 thesis (Dolan) and then 1993 Science. 
The 1989 work was also the first preparation of amorphous Boron nitride by B-trichloroborazine and cesium metal.
Boron nitride nanotubes were predicted in 1994 and experimentally discovered in 1995.
They can be imagined as a rolled up sheet of h-boron nitride. 
Boron nitride nanotube is a close analog of the carbon nanotube except carbon atoms are alternately substituted by nitrogen and boron atoms. 
However, the properties of Boron nitride nanotubes are very different: 
Carbon nanotubes can be metallic or semiconducting depending on the rolling direction and radius. 
A Boron nitride nanotube is an electrical insulator with a bandgap of ~5.5 eV, basically independent of tube chirality and morphology.
In addition, a layered Boron nitride structure is much more thermally and chemically stable than a graphitic carbon structure.
Boron nitride nanotubes (Boron nitrideNTs) have many application areas thanks to their superior properties such as:
thermal and electrical insulation
resistance to oxidation
high hydrophobicity
high hydrogen storage capacity as well as biocompatible properties
Therefore, new synthesis methods are being searched for Boron nitrideNT with increasing interest in recent years. 
In this study, high purity and yield Boron nitrideNTs were synthesized using precursor materials and methods that were not previously tried in the literature. 
A chemical vapor storage (CVD) furnace was used for the synthesis, and various parameters were changed to achieve optimum conditions. 
The structure of the obtained Boron nitrideNTs was characterized by Fourier conversion infrared spectroscopy (FTIR), Raman spectroscopy, and a UV-visible spectrophotometer. 
In addition, surface morphologies were illuminated using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). 
However, it has been observed that Boron nitrideNTs obtained as a result of HR-TEM (high-resolution transmission electron microscope) analysis have a single-walled structure that is difficult to synthesize. 
This increases the importance and quality of synthesized Boron nitrideNTs.
Boron nitride aerogel is an aerogel made of highly porous Boron nitride. 
Boron nitride aerogel typically consists of a mixture of deformed Boron nitride nanotubes and nanosheets. 
Boron nitride aerogel  can have a density as low as 0.6 mg/cm3 and a specific surface area as high as 1050 m2/g, and therefore has potential applications as an absorbent, catalyst support and gas storage medium. 
Boron nitride aerogels are highly hydrophobic and can absorb up to 160 times their weight in oil. 
They are resistant to oxidation in air at temperatures up to 1200 °C, and hence can be reused after the absorbed oil is burned out by flame. 
Boron nitride aerogels can be prepared by template-assisted chemical vapor deposition using borazine as the feed gas.
Addition of boron nitride to silicon nitride ceramics improves the thermal shock resistance of the resulting material. 
For the same purpose, Boron nitride is added also to silicon nitride-alumina and titanium nitride-alumina ceramics. 
Other materials being reinforced with Boron nitride include:
alumina and zirconia
borosilicate glasses
glass ceramics
enamels
composite ceramics with titanium boride-boron nitride
titanium boride-aluminium nitride-boron nitride
silicon carbide-boron nitride composition
Hexagonal boron nitride (h-Boron nitride) is widely used in modern technologies due to a complex of physical and chemical properties such as:
-high thermal stability
-resistance to oxidation at high temperatures
-chemical resistance
-dielectric strength
-low density
-low coefficient of friction. 
h-Boron nitride forms a series of nanostructures: nanoparticles – smooth or with a petallike surface, and solid or hollow; 
nanotubes – cylindrical, polygonal, spiral, bamboo-like, and others; thin graphene-like petals; nanocages; nanocones and mesoporous Boron nitride. 
Boron nitride nanomaterials are actively studied as materials for nanooptical-magnetic devices, catalysis and biotechnologies. 
Boron nitride nanostructures retain the physical–chemical properties inherent to the bulk Boron nitride. 
In addition, straight Boron nitride nanotubes (Boron nitrideNTs) and graphene-like Boron nitride petals (Boron nitrideGPs) exhibit exceptionally high mechanical strength because of the perfection in their crystal structure. 
This makes Boron nitrideNTs and Boron nitrideGPs promising materials for producing high-strength composites based on polymer, ceramic and metal matrixes.
In our lab we we are developing new methods of Boron nitride nanostructures synthesis, studying physical, chemical and mechanical properties of various Boron nitride nanomaterials for their smart applications.
Boron nitride is synthesized via the reaction of a boron precursor (either boric acid or boron trioxide) with a nitrogen-containing reagent (urea or ammonia) under a nitrogen atmosphere.
This reaction yields amorphous boron nitride containing trace amounts of boron trioxide impurities, which may be further purified by evaporation via heating above 1500°C.

Applications of Boron Nitride:
Hexagonal Boron nitride (h-Boron nitride) is the most widely used polymorph. 
Hexagonal Boron nitride is a good lubricant at both low and high temperatures (up to 900 °C, even in an oxidizing atmosphere). 
h-Boron nitride lubricant is particularly useful when the electrical conductivity or chemical reactivity of graphite (alternative lubricant) would be problematic. 
In internal combustion engines, where graphite could be oxidized and turn into carbon sludge, h-Boron nitride with its superior thermal stability can be added to engine lubricant.
However, with all nano-particles suspension, Brownian-motion settlement is a key problem.
Settlement can clog engine oil filters, which limits solid lubricants application in a combustion engine to only automotive race settings, where engine re-building is a common practice. 
Since carbon has appreciable solubility in certain alloys (such as steels), which may lead to degradation of properties, Boron nitride is often superior for high temperature and/or high pressure applications. 
Another advantage of h-Boron nitride over graphite is that its lubricity does not require water or gas molecules trapped between the layers. 
Therefore, h-Boron nitride lubricants can be used even in vacuum, e.g. in space applications. 
The lubricating properties of fine-grained h-Boron nitride are used in cosmetics, paints, dental cements, and pencil leads.
Hexagonal Boron nitride was first used in cosmetics around 1940 in Japan. 
However, because of its high price, h-Boron nitride was soon abandoned for this application. 
Hexagonal Boron nitride's use was revitalized in the late 1990s with the optimization h-Boron nitride production processes.
Currently h-Boron nitride is used by nearly all leading producers of cosmetic products for foundations, make-up, eye shadows, blushers, kohl pencils, lipsticks and other skincare products.
Because of its excellent thermal and chemical stability, boron nitride ceramics are traditionally used as parts of high-temperature equipment. 
h-Boron nitride can be included in ceramics, alloys, resins, plastics, rubbers, and other materials, giving them self-lubricating properties. 
Such materials are suitable for construction of e.g. bearings and in steelmaking.
Plastics filled with Boron nitride have less thermal expansion as well as higher thermal conductivity and electrical resistivity. 
Due to the excellent dielectric and thermal properties of boron nitride, Boron nitride is used in electronics e.g. as a substrate for semiconductors, microwave-transparent windows.
Many quantum devices use multilayer h-Boron nitride as a substrate material. 
Boron nitride can also be used as a dielectric in resistive random access memories.
Hexagonal Boron nitride is used in xerographic process and laser printers as a charge leakage barrier layer of the photo drum.
In the automotive industry, h-Boron nitride mixed with a binder (boron oxide) is used for sealing oxygen sensors, which provide feedback for adjusting fuel flow.
The binder utilizes the unique temperature stability and insulating properties of h-Boron nitride.
Parts can be made by hot pressing from four commercial grades of h-Boron nitride. 
Grade HBoron nitride contains a boron oxide binder; it is usable up to 550–850 °C in oxidizing atmosphere and up to 1600 °C in vacuum, but due to the boron oxide content is sensitive to water. 
Grade HBR uses a calcium borate binder and is usable at 1600 °C. 
Grades HBC and HBT contain no binder and can be used up to 3000 °C.
Boron nitride nanosheets (h-Boron nitride) can be deposited by catalytic decomposition of borazine at a temperature ~1100 °C in a chemical vapor deposition setup, over areas up to about 10 cm2. 
Owing to their hexagonal atomic structure, small lattice mismatch with graphene (~2%), and high uniformity they are used as substrates for graphene-based devices.
Boron nitride nanosheets are also excellent proton conductors. Their high proton transport rate, combined with the high electrical resistance, may lead to applications in fuel cells and water electrolysis.
h-Boron nitride has been used since the mid-2000s as a bullet and bore lubricant in precision target rifle applications as an alternative to molybdenum disulfide coating, commonly referred to as "moly". 
Hexagonal Boron nitride is claimed to increase effective barrel life, increase intervals between bore cleaning, and decrease the deviation in point of impact between clean bore first shots and subsequent shots.
Hexagonal boron nitride (HBoron nitride) is a solid lubricant relating to the class of Inorganic lubricants with lamellar structure, which also includes:
-molybdenum disulphide
-graphite
-some other sulphides, selenides and tellurides (chalcogenides) of molybdenum
-tungsten
-niobium
-tantalum
-titanium
The crystal lattice of hexagonal boron nitride consists of hexagonal rings forming thin parallel planes. 
Atoms of boron and nitrogen are covalently bonded to other atoms in the plane with the angle 120 °between two bonds.
The planes are bonded to each other by weak Van der Waals forces.
The layered structure allows sliding movement of the parallel planes. 
Weak bonding between the planes provides low shear strength in the direction of the sliding movement but high compression strength in the direction perpendicular to the sliding movement.
Friction forces cause the particles of boron nitride to orient in the direction, in which the planes are parallel to the sliding movement. 
The anisotropy of the mechanical properties imparts the combination of low coefficient of friction and high carrying load capacity to boron nitride.Boron nitride forms a lubrication film strongly adhered to the substrate surface. The lubrication film provides good wear resistance and seizure resistance (compatibility).
Similar to molibdenum disulfide moist atmosphere is not required for lubrication by boron nitride. 
Hexagonal Boron nitride demonstrates low friction in dry atmosphere and in vacuum.
Coefficient of friction of boron nitride is within the range 0.1-0.7, which is similar to that of graphite and molybdenum disulfide. 
Impurities (eg. boron oxide) exert adverse effect on the lubrication properties of boron nitride.
Boron nitride is chemically inert substance. 
Hexagonal Boron nitride is non-reactive to most acids, alkalis, solvents and non-wetted by molten aluminum, magnesium, molten salts and glass.
The main advantage of boron nitride as compared to graphite and molybdenum disulfide is its thermal stability. 
Hexagonal boron nitride retains its lubrication properties up to 5000°F (2760°C) in inert or reducing environment and up to 1600°F (870°C) in oxidizing atmosphere.
Cubic boron nitride (CBoron nitride or c-Boron nitride) is widely used as an abrasive.
CBoron nitride's usefulness arises from its insolubility in iron, nickel, and related alloys at high temperatures, whereas diamond is soluble in these metals. 
Polycrystalline c-Boron nitride (PCBoron nitride) abrasives are therefore used for machining steel, whereas diamond abrasives are preferred for aluminum alloys, ceramics, and stone. 
When in contact with oxygen at high temperatures, Boron nitride forms a passivation layer of boron oxide. 
Boron nitride binds well with metals, due to formation of interlayers of metal borides or nitrides. 
Materials with cubic boron nitride crystals are often used in the tool bits of cutting tools. 
For grinding applications, softer binders, e.g. resin, porous ceramics, and soft metals, are used. 
Ceramic binders can be used as well. Commercial products are known under names "Borazon" (by Diamond Innovations), and "Elbor" or "Cubonite" (by Russian vendors).
Contrary to diamond, large c-Boron nitride pellets can be produced in a simple process (called sintering) of annealing c-Boron nitride powders in nitrogen flow at temperatures slightly below the Boron nitride decomposition temperature. 
This ability of c-Boron nitride and h-Boron nitride powders to fuse allows cheap production of large Boron nitride parts.
Similar to diamond, the combination in c-Boron nitride of highest thermal conductivity and electrical resistivity is ideal for heat spreaders.
As cubic boron nitride consists of light atoms and is very robust chemically and mechanically.
CBoron nitride is one of the popular materials for X-ray membranes: low mass results in small X-ray absorption, and good mechanical properties allow usage of thin membranes, thus further reducing the absorption.
Layers of amorphous boron nitride (a-Boron nitride) are used in some semiconductor devices, e.g. MOSFETs.
They can be prepared by chemical decomposition of trichloroborazine with caesium, or by thermal chemical vapor deposition methods. 
Thermal CVD can be also used for deposition of h-Boron nitride layers, or at high temperatures, c-Boron nitride.

Applications of Boron Nitride:
The hexagonal form of boron nitride is used as lubricant for paints, cosmetics, pencil lead, and cement for dental applications. 
The lubricating property of boron nitride occurs even in the absence of gas or water molecules within the compound layers, thereby making it a good component for vacuum systems.
Compared to graphite, Boron nitride has significantly better chemical stability and electrical conductivity.
The exceptional resistance of boron nitride to heat lends the compound to a wide variety of applications involving extremely high temperatures. 
Hexagonal boron nitride is being used to improve the lubricating properties of rubber, plastic, alloys, and ceramics.
In the case of plastics, inclusion of a Boron nitride component provides lower thermal expansion. 
Boron nitride may also be integrated into semiconductor substrates and microwave oven windows.
Boron nitride is an effective component of reaction vessels and crucibles because of boron nitride's thermochemical properties.
With a bandgap ranging from 4.5 to 6.4 eV, boron nitride is an excellent wide-gap semiconductor material. 
The intrinsic thermal and dielectric properties of boron nitride make it a suitable substrate in developing metal-oxide-semiconductor field-effect transistors (MOSFETs) and semiconductors.
Due to the physical properties of cubic boron nitride.
This polymorph is used as abrasive material for nickel, iron, and selected alloys in conditions where diamond was not found to be suitable (such as under extreme heat). 
The cubic Boron nitride form of boron nitride is incorporated in cutting-tool bits and grinding equipment.
The high thermal conductivity of Boron nitride nanoparticles is utilized in nanofluids. 
Adding Boron nitride nanoparticles to conventional heat transfer fluids improves the thermal conductivity and consequently enhances the thermal transport.
Nanofluids can be used in heat exchangers for rapid cooling or heating applications.
Superior mechanical strength of Boron nitride nanoparticles is used to construct ultra-hard cubic Boron Nitride (c-Boron nitride) with Vickers Hardness larger than 100 GPa. 
This value exceeds the optimal hardness of synthetic diamonds. In addition to unique mechanical toughness, c-Boron nitride also shows considerable fracture toughness and high oxidation resistance.
Due to these unique properties, c-Boron nitride can be utilized as a high-performance abrasive material in place of diamond. Furthermore, c-Boron nitride is effective at precise sculpting of ferrous based materials.
Much like carbon nanotubes, Boron nitride nanotubes are utilized as a reinforcement agent in composites. 
Boron nitride nanotubes are used as composite fillers mostly in polymer, ceramic and metal composites. 
Due to their high mechanical strength and thermal conductivity, Boron nitride nanotubes improve the strength of these composites while also improving the thermal conductivity of the material. 
The thermal conductivity of different polymers can be increased by 4.5 to 14.7 times with different loading ratios.
Another application of Boron nitride nanotubes is hydrogen uptake and storage. 
Due to their high surface area and polarity Boron nitride nanotubes have the potential to be used as hydrogen storing materials in the hydrogen energy industry.
Other promising application areas of Boron nitride nanotubes are; insulating coatings, ultraviolet luminescence, and field emission. 
Due to the wide bandgap of h-Boron nitride structure, Boron nitride nanotubes present high electrical insulating properties.
Much like Boron nitride nanotubes, Boron nitride nanosheets are used as a reinforcing agent in polymers. 
Along with mechanical strength, Boron nitride nanosheets offer better thermal conductivity than Boron nitride nanotubes and provide chemical stability against degradation. 
Boron nitride nanosheets are excellent additives for polymers and other composites. Boron nitride based composites also have the potential to be used in the packaging industry because of their high thermal conductivity.
Alternatively, Boron nitride nanosheets are used in microelectronic applications. 
Combining semiconducting properties of carbon nanostructures with insulating properties of Boron nitride nanosheets enables the construction of electrical circuits, field-effect transistors, and tunneling devices. 
Moreover, the smooth surface of Boron nitride nanosheets can improve the device quality and performance while chemical inertness of Boron nitride nanosheets offers protection against corrosion.
Carbon-doped Boron nitride nanosheets show excellent photocatalytic properties and have the potential to be used as a photocatalyst in H2 production and oxidation of water pollutions.
Other possible application areas of Boron nitride nanosheets can be listed as; lubricants, superhydrophobic materials, and oxidation-resistant coatings.
Nanoporous Boron nitride combines the excellent Boron nitride properties with the high surface area of the porous structure. 
High chemical stability and thermal conductivity of the porous Boron nitride allow its use in hydrogen storage, catalyst support, pollution treatment, and drug delivery systems.
Adsorption properties of porous Boron nitride structures are used for water pollution treatments. 
Inorganic particles such as heavy metals and sulfate, phosphate, nitrate, and chloride anions; organic particles such as dyes cause water pollution. 
The high concentrations of these pollutions threaten human and animal health and the environment.
Thus, water treatment is a necessity in our world. 
The high surface area and chemical inertness of porous Boron nitride are suitable for pollutant removal.
Porous Boron nitride can uptake 3300 wt% of the adsorbates exhibiting a great removal potential. 
Furthermore, they have great cycling performances allowing the material to be used for a long period of time.
Much like Boron nitride nanotubes, porous Boron nitride nanostructures can be used for hydrogen storage applications. 
Under 1 MPa and at 77K, nanoporous Boron nitride was found to uptake 2.6 wt% hydrogen.

Chemical and Physical Properties:
ChEBI: CHEBI:50883 
ChemSpider: 59612 
ECHA InfoCard: 100.030.111 
Gmelin Reference: 216
MeSH: Elbor
PubChem CID: 66227
RTECS number: ED7800000
UNII: 2U4T60A6YD 
CompTox Dashboard (EPA): DTXSID5051498
Hydrogen Bond Donor Count: 0    
Hydrogen Bond Acceptor Count: 1    
Rotatable Bond Count: 0    
Exact Mass: 25.0123792    
Monoisotopic Mass: 25.0123792    
Topological Polar Surface Area: 23.8 Ų    
Heavy Atom Count: 2    
Formal Charge: 0    
Complexity: 10    
Isotope Atom Count: 0    
Defined Atom Stereocenter Count: 0    
Undefined Atom Stereocenter Count: 0    
Defined Bond Stereocenter Count: 0    
Undefined Bond Stereocenter Count: 0    
Covalently-Bonded Unit Count: 1    
Compound Is Canonicalized    : Yes    

Synonyms:
Boron nitride
10043-11-5
Elbor
azanylidyneborane
Boron nitride (Boron nitride)
Denka boron nitride GP
Boron Nitride Nanotubes
MFCD00011317
Boron nitride
Boron nitride, 98%
Borazon
Elboron
Kubonit
Boron Nitride dispersion
Wurzin
Boron nitride, low binder
Geksanit R
Hexanite R
Boron mononitride
Hexanit R
Super mighty M
Kubonit KR
Hexagonal boron nitride ink
Elbor R
Denka GP
Elbor RM
Sho Boron nitride
UHP-Ex
Sho Boron nitride HPS
SP 1 (Nitride)
Boron nitride 40SHP
KBoron nitride-H10
Elbor LO 10B1-100
BZN 550
EINECS 233-136-6
UNII-2U4T60A6YD
Bornitrid
nitrure de bore
nitruro de boro
Nano Boron Nitride
Boron nitride paste
Boron Nitride Nanopowder
Boron Nitride Micropowder
Boron Nitride NanoBarbs?
Boron Nitride Nanoparticles
EC 233-136-6
Hexagonal Boron Nitride Powder
[Boron nitride]
2U4T60A6YD
Boron Nitride Sputtering Target
DTXSID5051498
Nano Boron Nitride Nanoparticles
CHEBI:50883
Boron Nitride Powder, 99% Nano
Boron Nitride Nanotubes Properties
Boron Nitride Nanoparticle Dispersion
AKOS015833702
Boron nitride Boron nitride GRADE C (H?gan?s)
Boron nitride, Aerosol Refractory Paint
Boron nitride, powder, ~1 mum, 98%
Boron nitride Boron nitride GRADE A 01 (H?gan?s)
Boron nitride Boron nitride GRADE B 50 (H?gan?s)
Boron nitride Boron nitride GRADE F 15 (H?gan?s)
FT-0623177
Y1456
Boron Nitride Nanotubes (B) Bamboo structure
LUBRIFORM? Boron Nitride Boron nitride 10 (H?gan?s)
LUBRIFORM? Boron Nitride Boron nitride 15 (H?gan?s)
Boron Nitride (hBoron nitride) Aerosol Spray (13Oz/369g)
Boron Nitride Nanotubes (C) Cylindrical structure
Q410193
Boron nitride, Refractory Brushable Paint, Boron nitride 10%
Boron nitride, Refractory Brushable Paint, Boron nitride 31%
J-000130
Boron nitride, nanoplatelet, lateral dimensions <5 mu
Tantalum Molybdenum (Ta-Mo) Alloy Sputtering Targets
Boron Nitride Rod,Diameter (mm), 12.7,Length (mm), 300
Boron Nitride Rod,Diameter (mm), 6.4,Length (mm), 300
Boron nitride, ERM(R) certified Reference Material, powder
Boron Nitride Bar,Length (mm), 300,Width (mm), 12.7,Height (mm), 12.7
Boron Nitride Bar,Length (mm), 300,Width (mm), 6.4,Height (mm), 6.4
Boron Nitride Rectangular Plate,Length (mm), 125,Width (mm), 125,Thick (mm), 12.7
Boron Nitride Rectangular Plate,Length (mm), 125,Width (mm), 125,Thick (mm), 6.4
Boron nitride sputtering target, 76.2mm (3.0in) dia x 3.18mm (0.125in) thick
Boron nitride, nanopowder, <150 nm avg. part. size (BET), 99% trace metals basis