Tungsten carbide powder is the main unfinished allied of producing cemented carbide. Its chemical formula is WC, called as Wolfram Carbide It is ominous hexagonal crystals, with metallic luster, the hardness is similar to diamond, is a behalf conductor of electricity and heat
The methods of preparing tungsten carbide by tungsten powder
Tungsten carbide does not dissolve in water, hydrochloric tart andsulfuric acid, soluble in nitric acid and hydrofluoric sour mixture. Pure tungstencarbide is fragile, if varying with a trivial unit of titanium, cobalt and othermetals can be reduced brittleness
Tungstencarbide is principally used for high-speed cutting tools, furnace structuralmaterials, jet apparatus parts, metal ceramic materials, resistance heatingelements and so on For the making of cutting tools, wear parts, copper,cobalt, bismuth and more metal melting crucible, wear-resisting semiconductorthin film. As superhard cutting mechanism materials, wear-resistant materials, it canform a insoluble key with mixed carbides It furthermore can be used as additivesof NbC-C and TaC-C ternary carbides, not only reduced the sinteringtemperature, but besides maintaining excellent performance, can be used asaerospace materials.
From metal powder supplier we declared that tungsten carbide was produced in two ways, one isused tungsten metal powder and charcoal as coarse material, cynical varying the averageparticle calibre of 3 ~ 5m tungsten powder and the identical cipher of substancecarbon gloomy with a ball mill, after widespread mixing, compression molding andput into a graphite plate, then heated to 1400 ~ 1700in a graphite resistance furnace or induction furnace, controlled at 1550 ~ 1650is best In a hydrogen stream, originally generated W2C, permanent act at a rangy temperature to generateWC Or top thermal decomposition W(CO)6 in650 ~ 1000, COatmosphere to recruit tungsten powder, then respond with carbon monoxide at 1150to gain WC, above this temperature can be generated W2C
Anotheris WO3 hydrogenation obtained tungsten powder (average particle size is 3 ~ 5m). Then compel molding thetungsten powder and carbon gloomy at the equimolar brew (dry mixing in a ballmill for 10h) under a impel of about 1t/cm2. Put the press molding materialinto the graphite disk or halt crucible, heated with the graphite resistancefurnace or induction furnace in a hydrogen gas flash to 1400 ~ 1700(preferably 1550 ~ 1650),make it carburized and generated WC The sensation was started from the tungstengrains around, because at the onslaught of the sentiment entrust grow W2C, since the warmth is not complete,in appendix to WC, it still remaining unreacted W and intermediates W2C, so it must be heated to the rangy temperatures
Tungstendust can front peribronchitis, peribronchiolar, blocking bronchiolitis andatrophic emphysema Tungsten carbide may bob lung lymphoid tissue cellproliferative response, and gradually emergence sclerosis Vascular handrail was thickeningand homogenization People exposure to tungsten carbide dust in job bequeath causegastrointestinal disorders, kidney suffered irritation, upper respiratory tractappeared catarrhal inflammation The maximum allowable concentration oftungsten carbide is 6mg/m3.
Staffshould use the satisfactory gas mask, dust-proof clothing, gloves, glassesPrevent dust leakage in all stages of forming Workers should dopre-employment physical examination, periodic evaluation once every year Whenthe upper respiratory tract appears obvious symptoms must temporarily transferwork, do not impression with tungsten If exhibit up lung hardening or respiratoryfunction disorders should be removed from the business Tungsten carbide should bestored in a cool, sardonic depot, earnings emphasis to test whether the packagingcontainers in sake condition during transport, discourage drop and sunlightexposure.