The Study Of Debinding And Sintering Process In Metal Powder Injection Molding Of Ti-Mo Getter Materical

The non evaporable Ti-Mo alloy getter material, a newly developed function-material with high mechanical strength and excellent getter capacity, is widely used in vacuum electron devices, which demands long service life, high properties and stability. However, the preparation technology of this material is lagging far behind the application requirements on miniaturization precision and mass production of the corresponding products. The metal injection molding process is adopted in this paper, and the solvent and thermal debinding, as well as the sintering process of the Ti-Mo alloy is studied and optimized, using a series of analysis methods such as SEM, XRD, DTA-TG, porosity, specific surface area and carbon content. The detailed research contents are listed as following:Four processing parameters of loading, type, temperature and time of solvent debinding, are studied and optimized in this study. It is shown that, the samples containing loading of40%were regarded as the most appropriate proportion of organic binders and metallic powders, leading to the largest porosity and specific surface. Trichloroethylene was found to have the best debinding effect on soluble binders, causing optimal porosity and specific surface. The optimized debinding temperature and time were60℃,6h, considering the optimization of porosity and specific surface area. The solvent debinding samples prepared based on the optimized parameters mentioned herein was considered as the precondition of the following researches on thermal debinding process.The parameters of heating rate and holding time are studied and optimized in the thermal debinding process from220℃to520℃. It is suggested that, the carbon content was increased with higher heating rate. The reduction of sorption property was caused by the lower porosity and specific surface area as well as higher carbon content. The largest porosity and specific surface area were found with holding time of20min, leading to the optimized getter property. The carbon content was reduced with longer holding time, and becomes steady with holding time longer than20min.The parameters of sintering temperature and holding time are studied and optimized in the sintering process of Ti-Mo injection specimen. It is deduced that, sorption property by sintering from750℃to900℃was better than that by presintering in680℃, and the sorption property was the best between750℃and800℃, the higher sintering temperature was, the more densification was, and the lower sorption property was. Lower bonding strength between the particles was obtained when holding time was not long enough, while fairly high density of the samples was found with excessively long holding time. Thus a proper holding time of10min was developed in this study, considering the optimization of porosity, specific surface area and getter property. The carbon content of the sample was further reduced and substantially improved getter property was obtained after sintering process, compared with that after thermal debinding process.Distinct advantages on homogeneity, miniaturization, complication, precision, mechanical strength, manufacturing cost production efficiency and mass production were found in the metal injection molding process studied in this paper, resulting in the production of samples with the optimization of sorption properties, compared with the other traditional processes such as compression molding and coating method.