The Preparation Of Zirconium Oxide Feedstock And Forming Technology Research For Powder Injection Molding

Powder Injection Molding (PIM) is a new net-shape forming technology, which is the result of plastic injection technology combined with powder metallurgy technology. The basic process of the PIM:powder and binder are mixed well, then the injection molding is finished using a injection molding machine. The binder is removed via debinding process. At last, via sintering process and a dense produce is prepared. PIM technology can be used in all kinds of metals, alloys, ceramics and so on for fomiing process.Ceramic Powder Injection Molding (CIM) is an important part in modern PIM technology. A lot of research have been done in preparation of zirconia ceramics via CIM technology. The zirconia ceramic with low viscosity and high solid content is difficult to be prepared via CIM. Many researchers study the influence of pH and binder on mobility of the mix. However, there is little research about the influence of mixing method on the dispersion of binder and on the properties of ceramic, and the theoretical system is not perfect.In this article, based on previous research and the problems reflected in it. in the second chapter by mixing high density polyethylene (HDPE) binder system with zirconia (ZrO2). we researched their mix situation between zirconia powder with different solid content and polyethylene (HDPE) binder system in two different ways of mixing using the kneading machine and mixer (the working principle of Mixing equipment in Torque rheometer is same as that of mixer).The decentralized state of binder system under different mixing way and different solid content was analyzed via contrasting the cross section of green before and after being debinding sing scanning electron microscopy (SEM). The easing rate and removal rate were analyzed via the method of immersion solvent degreasing. Based on the thermal behaviors of mixed materials. which was analyzed using simultaneous thermal analysis (TG). the parameters of thermal degreasing were determined. The surface and cross section of green after the high temperature furnace sintering were studied using SEM. In order to analyze the stability of the various aspects, the density and quality were studied at the same time. In the third chapter by mixing high density polyethylene (HDPE) binder system with zirconia (ZrO2), we researched the mix situation between zirconia powder with different solid content and Polypropylene (PP) adhesive system and analysed the dispersion of Polypropylene (PP) adhesive system in the ZrO2 powder. At the same time comparing the dispersion and mix situation with that of HDPE binder system and the mixture of ZrO2 and the dispersion. Two types of mixing by used to compared with their mixing situation and dispersion toward HDPE binder systern and PP binder system with ZrO2 powder by kneading machine and mixer, and analysed the effect of different mixing state to quality, size and density of solvent degreasing. green and sintered products.Based on findings in the study the following conclusions have been drawn:(1) We can draw the best powder loading capacity and mixing time via two kinds of method to prepare feed mixing and to determinate the torque by Kneading machine and mixer. (2) The green cross section before and after being solvent degreased were analyzed using SEM. Compared with kneading machine, the composites mixed in mixer had the binder and the powder mixed more thoroughly, more weakly agglomerated, less porosity, obvious higher polymer macroscopic network structure. Compared with composites with low solid content, so did the composites with high solid content. (3) The appropriate temperature range of thermal degreasing. sintering temperature controlling and binder was determined using TG. (4) Via analyzing the size and the quality of green and the product before and after being sintered, we knew that the quality, size stability of green and products is good nearby the best solid content. (5) The size shrinkage, cross section, density and surface SEM photographs of products before and after being sintered were studied. After being sintered, the product with high solid content has higher sintering density, smaller internal pores, smoother surface less surface holes, higher internal density.In this article, it provides a meaningful method for the preparation of feed, injection molding and debinding and sintering process via a series of experiments and the test results.