还原碳化法制备超细碳化铬粉末

以纳米Cr_2O_3和乙炔黑为原料,经高温还原碳化制备超细Cr_3C_2粉末,研究反应温度、反应时间以及配碳量对Cr_3C_2粉末的粒度与游离碳含量的影响。通过热力学计算,只有当温度高于1 350 K时还原碳化反应才有可能进行,采用纳米Cr_2O_3可显著降低反应温度,在1 573 K下焙烧6 h碳化率即达到98.20%;Cr_3C_2粉末的游离碳含量随配碳量增加而显著提高,配碳量(质量分数)为理论配碳量的1.05倍时制得游离碳含量为0.23%、氧含量为0.91%(均为质量分数)、平均粒度为1μm的Cr_3C_2粉末,该粉末达到硬质合金及热喷涂应用的要求。

Preparation of ultrafine chromium carbide powder by carbon reduction and carburization

Ultrafine chromium carbide powder was prepared through carbon reduction and carburization process with nanometer chromic oxide and acetylene black. The effects of reaction temperature, reaction time and carbon addition on the particle size and free carbon content of Cr3C2 powder were studied. Thermodynamics calculation and analysis show that the reaction will not start until the temperature is higher than 1350 K. It is observed that the reaction temperature decreases significantly due to using of nanometer raw material. The carbonation ratio is 98.20% after roasting for 6 h at 1573 K; The free carbon content of Cr3C2 powder increases sharply with increasing carbon addtion. When carbon addition is 105%, chromium carbide powder with average particle size of 1μm, free carbon content of 0.23% and oxygen content of 0.91% are obtained, and it can meet the technical requirements for thermal spraying and cemented carbide production.