大尺寸ZrO2注射成型坯体热脱脂缺陷成因探究

采用蜡基ZrO2粉末喂料注射成型获得大尺寸ZrO2陶瓷粉末注射产品（坯体），并根据喂料热分析曲线的变化特点，系统研究了大尺寸ZrO2坯体的热脱脂过程及规律。通过对热脱脂前后坯体的重量损失、尺寸收缩、外观缺陷和微观组织形貌的分析评估，着重探讨了大尺寸ZrO2坯体热脱脂过程中存在的主要缺陷和成因。研究表明，流蜡、鼓泡和开裂等热脱脂缺陷主要发生在低温脱脂阶段，其主要原因是液态石蜡扩散及分解过程的失衡。为此，结合“失重率控制”的思路和喂料的热失重规律，对热脱脂工艺进行了优化，在不延长总脱脂时间的前提下，显著提高了大尺寸ZrO2坯体的脱脂合格率。

Study on Thermal Debinding Defects of Large Size ZrO2 Green Compacts by Ceramic Injection Molding

The wax--based ZrO2 power feedstock was used to obtain large size ZrO2 ceramic injection molding products （green compacts） . According to the thermal analysis results of the feedstock, the thermal debinding processes and rules of the large size ZrO2 green compacts were systematically investigated. By analyzing and evaluating the weight loss of the green compacts, size shrinkage, defects on the surfaces and microstructure morphologies before and after the thermal debinding, the main defects and their causes have been specifically discussed. Research shows that the flow of wax, bubbling, cracking and other thermal debinding defects mainly occurred in the low temperature stage. The main causes were the imbalance of the liquefied wax diffusion and its decomposition. Based on the ＂weight loss controlling＂ theory and the thermo--gravimetric rules of the feedstock, the thermal debinding process was optimized. The thermal debinding qualified rate of large size ZrO2 green compacts was significantly increased without extending total debinding time.