金属注射成形蜡基粘结剂的改进

粘结剂体系在注射成形(MIM)工艺中起十分重要的作用,粘结剂体系的选择需要从相容性、流变性能、注射成形性及脱脂性能等许多方面加以考虑,作者研究了综合蜡基和油基粘结剂优点的改进型蜡基粘结剂体系,其组成为PP/PW/油/SA/改性剂,改进型蜡基粘结剂分阶段热解,各组元间有较强的相互作用,相容性较好,该粘结剂和金属粉末具有较好的混合均匀性,改性剂的加入提高了粉末装载量,喂料是一种假塑性流体,非牛顿指数n较大,粘流活化能ΔE_η较低,具有良好的注射填充性,改进型蜡基粘结剂既可热脱脂,又可溶剂脱脂。

Study on the improved wax-based binder for metal injection molding

The binder system plays an important role in metal injection molding (MIM) processing and a suitable binder system can be determined by solubility, chemical compatibihty, theology, moldabihty and debinding completeness. The improved wax-based binder for MIM, which had advantages of wax-based binder and oil-based binder, was composed of polypropylene, paraffin wax, castor oil, stearic acid, and modifer. The binder included several decomposition stages in the thermal analysis, and had good compatibility due to adding the modifer. The binder had good adhesion to metal powder, and can be mixed homogeneous with Fe-2Ni powder, and had a higher solids loading. The feedstock exhibited good molding and rhelogicla characterisation. The feedstock possessed pseudo plasticity, the power law exponent and the activating energy for viscous flow were suitable for MIM. The binder could be debound by thermal bebinding or solvent debinding.