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将同一批超细钨粉,分成两组进行配炭,一组不添加抑制剂,另一组添加一定量Cr_3C_2和VC,分别将两组样品分成若干小样,在真空和氢气气氛中,采用不同温度进行碳化,分析不同WC样品粉末性能,并将1 200℃碳化的WC样品制备成钴含量为8%的硬质合金,比较合金性能及金相组织的差异。实验结果表明:在氢气气氛下,钨粉更易于碳化,碳化速度更快,WC的结晶更完整;碳化阶段添加抑制剂会抑制WC晶粒的长粗,但也抑制了WC晶粒生长的完整性;提高碳化温度可以改善WC的结晶完整性,WC的粒度也会随温度的升高而增大。氢气气氛碳化的WC制备成合金后晶粒度比真空碳化的WC粗,合金晶粒的均匀性更好,异常长粗的晶粒少;在碳化阶段添加抑制剂可以更好的抑制合金晶粒的长粗,同时也抑制了WC粉末晶粒结晶的完整性,从而导致合金在液相烧结阶段晶粒的异常长粗。
The same batch of ultrafine tungsten powder was divided into two groups with charcoal, one group without adding inhibitors, the other group adding a certain amount of Cr_3C_2 and VC, the two groups of samples were divided into several small samples, vacuum and hydrogen atmosphere, using different The carbonization temperature was used to analyze the powder properties of different WC samples. The WC samples prepared at 1 200 ℃ were hardened to 8% cobalt, and the differences of the properties and the microstructure of the alloys were compared. The experimental results show that under the hydrogen atmosphere, the tungsten powder is more easily carbonized, the carbonization speed is faster, and the crystallization of WC is more complete. Adding inhibitors in the carbonization stage can inhibit the growth of WC grains but also inhibit the growth of WC grains ; Increasing the carbonization temperature can improve the crystal integrity of WC, and the grain size of WC increases with the increase of temperature. Hydrogen atmosphere carbonized WC prepared alloy grain size than vacuum carbonized WC rough, alloy grain uniformity is better, abnormal long coarse grains less; addition of inhibitors in the carbonization stage can better inhibit the alloy grains Of the coarse, but also inhibit the integrity of WC powder crystal grains, resulting in the alloy phase in the liquid phase sintering abnormal coarse grains.