BORON NITRIDE POWDER
Boron Nitride Powder Applied To High-Grade Refractory And Superhard
Material
Property:
Boron nitride is a type of crystal made up of nitrogen atom and
boron atom. Its crystal structure is HBN, WBN and cubic boron
nitride. The crystal structure of HBN, similar to graphite layer,
is loose, lubricative white powder that can easily absorb moisture
and is light in weight, hence the name “white graphite”. Its
theoretical density: 2.27g/cm3, specific gravity:2.43, Mullite
hardness:2. HBN shows desirable insulativity and thermal
conductivity, stable chemical property and without sharp melting
point. When mixing with 0.1MPA nitrogen, it can resist heat of
3000℃; when in neutral reducing atmosphere,it can resist heat of
2000℃; when used in nitrogen and argon, the application temperature
can be 2800℃. HBN shows poorstability when in oxygen and the usage
temperature is below 1000℃. The dilatation coefficient of HBN is
the same as that of quartz, but its thermal conductivity is ten
times that of quartz.
HBN is insoluble in cold water. When boiled in water, its
hydrolyzation process is very slow and will generate a small amount
of boric acid and ammonia. It will not react with weak acid and
alkali in indoor temperature and is slightly soluble in hot acid.
Besides, it can resolve when treated with molten sodium hydroxide
and potassium hydroxide.
Performance parameters of boron nitride:
1. High heat resistance: It will sublime at 3000℃; When at 1800℃,
its strength is twice of when in room temperature. It will not
break when cooling from 1500℃ to room temperature for dozens of
times, and will not become soft when in inert gases of 2800℃.
2. Property of high conductivity: Hot pressed product is 33W/M.K,
the same as pure iron. When above 530℃, it has the largest thermal
conductivity among ceramic materials when above 530℃.
3. Low coefficient of thermal expansion: Its coefficient of thermal
expansion is 2×10-6, second to quartz glass and the lowest among
ceramics. With its high thermal conductivity, it has high thermal
shock resistance.
4. Excellent electrical property: excellent high temperature
insulation; when at 25℃, it can reach 1014Ω-cm, and can reach
103Ω-cm when at 2000℃.So it is the best high-temp. insulating
material among ceramics. When the breakdown voltage is 3KV/MV and
the low dielectric loss is 108HZ, it can reach 2.5×10-4, the
dielectric constant is 4 and can penetrate microwave and infrared
ray.
5. Great corrosion resistance: It will not react with ordinary
metal (iron, copper, aluminum, lead and so on), rare earth metal,
precious metal, semiconductor materials (germanium, silicon,
potassium arsenide), glass, fused salt (crystal, fluoride and
slag), mineral acid, and alkali.
6. Low friction coefficient: U is 0.16, and will not increase in
high temperature. It has a greater resistance to high temperature
than molybdenum disulfide and graphite. The oxidizing atmosphere
can be 900℃; when in vacuum, it can be used at 2000℃.
7. High purity and higher B: Its impurity content is lower than
10PPM and the B content is over 43.6%.
8. Machinability: Its hardness is Mohs 2, so it can be processed
into parts and components of high precision by means of general
mechanical processing.
Application of HBN:
HBN can be used to produce TiB2/BN composite ceramic and can also
be applied to high-grade refractory and superhard material. The
separating ring of horizontal continuous forging steel can be used
as high-temperature lubricant, high-temperature paint, and the raw
material of synthetic cubic boron nitride.
We supply a full series of HBN Powder, Spherical BN, and Nano BN
spheres. Please contact us for more detailed product information.