(1.中南大学 粉末冶金国家重点实验室，长沙 410083；
2. 北京科技大学 材料 科学与工程学院，北京 100083；
3. 中南大学 材料科学与工程系，长沙 410083)
摘 要: 研究了不同脱脂气氛(不同比例N2与H2的混合气体)和脱脂方法(热脱脂、溶剂脱脂+热脱脂、冷凝蒸汽脱脂+热脱脂)对PIM硬质合金脱脂坯及合金碳含量的影响。结果表明：N2热脱脂粘结剂容易以炭黑的形式残留在脱脂坯中，造成合金增碳；H2热脱脂导致合金脱碳；75%N2+25%H2(体积分数)混合气体热脱脂既能有效地脱除粘结剂，又能保证合金碳含量相对稳定；溶剂脱脂和冷凝溶剂脱脂能显著缩短脱脂时间，而且由于高温保持时间短，在后续热脱脂过程中采用H2作保护气也可获得满意的碳含量，说明该方法对工艺条件的适应性强。通过调整热脱脂高温保持时间，可在一定范围内对脱脂坯的碳含量进行调整，说明过程的可调控性好。与溶剂脱脂相比，冷凝蒸气脱脂粘结剂脱除率更高，脱脂坯有较高的强度，有效地防止了脱脂坯软化变形的现象。
关键字: PIM；热脱脂；溶剂脱脂；冷凝蒸汽脱脂；硬质合金；碳含量
process of cemented carbide made by
powder injection molding
（1.State Key Laboratory for Powder Metallurgy，
Central South University，Changsha 410083，China；
2.School of Materials Science and Engineering，University of
Science and Technology Beijing，Beijing 100083，China；
3. Department of Materials Science and Engineering，
Central South University，Changsha 410083，China）
Abstract:Carbon control of WC-8%Co tungsten cemented carbide during debinding process of powder injection molding was investigated. Effects of debinding method including thermal debinding，solvent debinding and condensed solvent debinding on carbon content were studied. The results show that thermal debinding in N2 atmosphere can not completely remove the binder，some binder residues leave behind as free carbon. Thermal debinding in H2 causes severe carbon loss while thermal de bin ding in 75%N2+25%H2 atmosphere gains an ideal carbon balance. Two step debinding method such as solvent debinding plus sequent thermal debinding and condensed so lvent debinding plus sequent thermal debinding can not only obviously reduce debinding time，but also endow the technology extensive flexibility to debinding a tmosphere and adjustability of carbon content. Moreover，compared with solvent de binding， condensed-solvent-debinding can remove binder more completely and gain debound specimens with higher strength.
Key words: powder injection molding; thermal debinding; solvent debinding; condensed-solvent-debinding; hardmetal; carbon content
