(1.中南大學(xué) 粉末冶金國家重點實驗室，長沙 410083；
2. 北京科技大學(xué) 材料 科學(xué)與工程學(xué)院，北京 100083；
3. 中南大學(xué) 材料科學(xué)與工程系，長沙 410083)
摘 要: 研究了不同脫脂氣氛(不同比例N2與H2的混合氣體)和脫脂方法(熱脫脂、溶劑脫脂+熱脫脂、冷凝蒸汽脫脂+熱脫脂)對PIM硬質(zhì)合金脫脂坯及合金碳含量的影響。結(jié)果表明：N2熱脫脂粘結(jié)劑容易以炭黑的形式殘留在脫脂坯中，造成合金增碳；H2熱脫脂導(dǎo)致合金脫碳；75%N2+25%H2(體積分數(shù))混合氣體熱脫脂既能有效地脫除粘結(jié)劑，又能保證合金碳含量相對穩(wěn)定；溶劑脫脂和冷凝溶劑脫脂能顯著縮短脫脂時間，而且由于高溫保持時間短，在后續(xù)熱脫脂過程中采用H2作保護氣也可獲得滿意的碳含量，說明該方法對工藝條件的適應(yīng)性強。通過調(diào)整熱脫脂高溫保持時間，可在一定范圍內(nèi)對脫脂坯的碳含量進行調(diào)整，說明過程的可調(diào)控性好。與溶劑脫脂相比，冷凝蒸氣脫脂粘結(jié)劑脫除率更高，脫脂坯有較高的強度，有效地防止了脫脂坯軟化變形的現(xiàn)象。
關(guān)鍵字: PIM；熱脫脂；溶劑脫脂；冷凝蒸汽脫脂；硬質(zhì)合金；碳含量
process of cemented carbide made by
powder injection molding
XIAO Ping-an1，QIN Ming-li1
（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
