The methods of preparing tungsten carbide by tungsten powder
Tungsten carbide powder is the paramount unprepared allied of producing cemented carbide. Its chemical formula is WC, called as Wolfram Carbide It is sinisteru hexagonal crystals, with metallic luster, the hardness is alike to diamond, is a good conductor of electricity and heat
The methods of preparing tungsten carbide by tungsten powder
Tungsten carbide does not dissolve in water, hydrochloric acrid andsulfuric acid, soluble in nitric acid and hydrofluoric sour concoction Pure tungstencarbide is fragile, if diverse with a derisory cipher of titanium, cobalt and othermetals can be reduced brittleness
Tungstencarbide is mostly used for high-speed cutting tools, furnace structuralmaterials, jet mechanism parts, metal ceramic materials, resistance heatingelements and so on For the making of cutting tools, wear parts, copper,cobalt, bismuth and other metal melting crucible, wear-resisting semiconductorthin film As superhard cutting machine materials, wear-resistant materials, it canform a hard guide with varying carbides It also can be used as additivesof NbC-C and TaC-C ternary carbides, not only reduced the sinteringtemperature, but furthermore maintaining admireable performance, can be used asaerospace materials
From metal powder supplier we proclaimed that tungsten carbide was produced in two ways, one isused tungsten metal powder and charcoal as fresh material, mocking miscellaneous the averageparticle thickness of 3 ~ 5m tungsten powder and the twin figure of substancecarbon npromising with a circle mill, after thorough 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, durable react at a gangling temperature to generateWC Or finest thermal decomposition W(CO)6 in650 ~ 1000, COatmosphere to levy tungsten powder, then cope with carbon monoxide at 1150to procure WC, above this temperature can be generated W2C
Anotheris WO3 hydrogenation obtained tungsten powder (average whit size is 3 ~ 5m). Then obligate molding thetungsten powder and carbon npromising at the equimolar assortment (dry mixing in a ballmill for 10h) underneath a require of about 1t/cm2. Put the manipulate molding materialinto the graphite disk or clog crucible, heated with the graphite resistancefurnace or induction furnace in a hydrogen gas glint to 1400 ~ 1700(preferably 1550 ~ 1650),make it carburized and generated WC The sentiment was started from the tungstengrains around, because at the attack of the warmth commit generate W2C, since the response is not complete,in appendage to WC, it idle remaining unreacted W and intermediates W2C, so it must be heated to the high temperatures
Tungstendust can vanguard peribronchitis, peribronchiolar, blocking bronchiolitis andatrophic emphysema Tungsten carbide may model lung lymphoid tissue cellproliferative response, and gradually emergence sclerosis. Vascular fortification was thickeningand homogenization People exposure to tungsten carbide dust in work commit 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 moulding Workers should dopre-employment physical examination, regular appraisal once every year. Whenthe upper respiratory tract appears obvious symptoms must temporarily transferwork, do not results with tungsten If declare up lung hardening or respiratoryfunction disorders should be removed from the task Tungsten carbide should bestored in a cool, ironic depot, honorarium importance to check whether the packagingcontainers in profit condition during transport, prohibit shower and sunlightexposure.
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