摘要
研究了超细硬质合金WC-6%Co注射坯的溶剂脱脂-热脱脂工艺,讨论了脱脂时间、脱脂温度、注射坯形状和固液比等工艺参数对溶剂脱脂速率的影响,通过改善溶剂脱脂-热脱脂工艺,得到了高性能超细硬质合金台阶状圆棒。结果表明:溶剂脱脂速率随着脱脂温度的升高而上升,随时间的延长而降低;溶剂脱脂3 h后,台阶状圆棒中可溶粘结剂基本脱除。溶剂脱脂时,弓形棒和台阶状圆棒的平均脱除速度较快,圆台棒的平均脱除速率较慢,即溶剂脱脂速率与注射坯的S/V(表面积/体积)值成正比。固液比越小,粘结剂平均脱除速率越高;在稳定阶段,残留可溶粘结剂量高的注射坯脱脂速率快。溶剂脱脂时,粘结剂从外向内脱除,内部可溶粘结剂在形成脱除通道后快速脱除。经过DSC分析,溶剂脱脂坯中存在少量高聚物共混物,需改善热脱脂工艺。优化脱脂工艺后,超细WC-6%Co硬质合金台阶状圆棒的碳含量合适,WC晶粒度为0.35μm,硬度HV10为1 828,致密度大于99%,尺寸精度高。
The solvent debinding-thermal debinding process of ultrafine-grained WC-6Co cemented carbide was studied in the paper. The effects of parameters including time, temperature, shape and solid-liquid ratio on solvent debinding process were analyzed. The ultrafine-grained cemented carbide stepped round bar with high properties was sintered, through the improvement of the solvent debinding-thermal debinding process. The results show that solvent debinding rate increases as the temperature increasing, and decreases as the time prolonging. The soluble binder is almost removed after 3h for the stepped round bar. Also it reveals that the debinding rate and average removed rate are higher for bow-shaped bar and stepped round bar, but lower for round table bar,which are according with the principle that the debinding rate is proportional to the ratio of surface to volume. And the average binder removal rate is higher with smaller solid-liquid ratio and with more residual soluble binder at the stable stage. When solvent debinding, soluble binder is removed quickly by the channel formed after binder done from the outside to inside. DSC results show that there is a smallamount of compound soluble binder, indicating that the debinding process should be optimized. After optimization, the sintered stepped round bar with proper carbon content, WC grain size of 0.35 μm, HV10 of 1828 and density of above 99%is prepared, and its dimensional accuracy is high.
出处
《硬质合金》
CAS
2014年第6期340-346,共7页
Cemented Carbides
基金
国家自然科学基金资助(项目号51101021)
关键词
超细
硬质合金
粘结剂
溶剂脱脂
热脱脂
ultrafine-grained
cemented carbide
binder
solvent debinding
thermal debinding
作者简介
谢兴铖（1986-），男，博士研究生，主要从事超细硬质合金注射成形。E-mail：xxc1014@126．com。
通讯作者：林晨光（1956-），男。博士生导师，主要从事先进硬质合金。E-mail：pm@grinm．com。
