粉末注射成形蜡基粘结剂溶剂脱脂行为研究

以YG8硬质合金为实验对象,研究了蜡基粘结剂注射成形生坯的溶剂脱脂行为,考察了时间、温度、生坯形状、厚度、表面积、粉末装载率和液固比对脱脂速率的影响,分析讨论了各因素影响脱脂速率的原因.结果表明:溶剂脱脂速率随温度升高而升高,随时间的延长而降低;脱脂初期扩散是控制性环节,温度是影响反应速率的主要因素,脱脂后期溶解成为控制性环节,浓度差减为影响反应速率的主要因素;液固比越大,脱脂速率越快,粘结剂最终脱除率越高;生坯粉末装载率越高,脱脂速率越慢,粘结剂最终脱除率越低;生坯形状对脱脂速率影响表现为样品厚度和表面积的影响,回归分析表明,脱脂速率与生坯表面积成正比,与生坯厚度的平方成反比.

Study on solvent debinding process of wax-based binder in powder injection molding

The solvent debinding process of wax-based binder in powder injection molding(PIM) was studiedsystematically. Effects of debinding temperature, shape, thickness, surface and powder loadng ofgreen parts, and liquid/solid ratio on solvent debinding behavior were investigated. It is found that thesovent debinding rate is high at the benginning, and then decreases; however, it would increase with tem-perature increase. The solvent debinding process is contrlled by diffusion initially, and temperature is.the dotminant parameter. Then it turns to dissolution control, the binder concentration become to be themost important factor. The bigger the volume raio of sovent and green parts is, the higher the debindingrate and binder loss ratio are. The larger the powder loading of green parts is, the lower the debindingrate and binder loss ratio are. The effect of green parts' shape on debinding rate is in essence the effectof green parts' surface area and thickness, and regression analysis indicates that debinding rate is in di-rect ratio with specimens' surface area, while it is in invese proprtion with the square of spechimens'thickness.