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颗粒特性各异的不同型号铁粉,以及标准牌号硬质合金粉末,与低分子量热塑性塑料和蜡配制的粘结剂混合,生产出适合注射成型的塑料熔胶。体积含量70％以下的金属粉末同蜡和低密度聚乙烯配成的粘结剂混合,可使塑料熔胶满足生产坚实成型件的流动性要求。从相当简单到比较复杂形状的试件,已经成功地在普通注射成型机和改型压铸机上用多腔模进行成型。测量的成型毛坯密度符合根据成分相对体积含量计算的理论值。去除粘结剂的研究结果用热解重量分析和用来生产较高密度试件的烧结工艺进行评定。发现最终密度受材料和工艺参数的影响,尤其是粉末颗粒特性、混合条件,去除粘结剂和烧结工艺。
Different types of iron powder with different particle characteristics, as well as standard grades of cemented carbide powders, are mixed with binders formulated with low molecular weight thermoplastics and waxes to produce a plastic melt suitable for injection molding. Mixing metal powders up to 70% by volume with a binder of wax and low-density polyethylene allows the plastic melt to meet the fluidity requirements for producing solid shaped parts. Specimens from fairly simple to more complex shapes have been successfully molded on multi-cavity molds on conventional and modified die-casting machines. The measured blank density conforms to the theoretical value calculated on the basis of the relative volume contents of the components. The results of the binder removal studies were evaluated by thermogravimetric gravimetric analysis and by the sintering process used to produce higher density specimens. The final density was found to be influenced by the material and process parameters, notably the particle characteristics of the powder, the mixing conditions, the binder removal and the sintering process.