氮化硅陶瓷中压注塑成型技术(MPIM)研究及进展

Research and Development of Medium Pressure Injection Molding Technology(MPIM)of Silicon Nitride Porcelain

首次采用中压注塑成型技术(MPIM)制得性能优良的氮化硅轴承球。研究了粘结剂配方、注塑成型、低缺陷排胶、气氛压力烧结等工艺参数对氮化硅轴承球致密度、力学性能、表面与微观形貌的影响。结果表明,喂料固含量55.51%、注塑速率5 cm/s、注塑温度90℃、注塑实际压力75 bar、超临界CO2萃取+热脱脂两步法排胶等工艺过程有效控制了氮化硅坯体的缺陷,制得了生坯致密度58.7%、烧结密度3.26 g/cm3、烧结致密度99.4%、抗弯强度843 MPa、无缺陷的氮化硅轴承球。MPIM是未来注塑成型技术发展的重点方向,具有广泛的应用前景。

The medium-pressure injection molding technology(MPIM)was applied to produce silicon nitride bearing balls with excellent performance for the first time.The effects of binder recipe,injection molding,low-defect debinding,and gas pressure sintering on the compactness,mechanical properties,surface and micro-morphology of Silicon Nitride bearing balls were studied.The results show while the solid content of the feedstock is 55.51%,the injection rate is 5 cm/s,the injection temperature is 90℃,the actual injection pressure is 75 bar,and the debinding process is two-step debinding of supercritical CO2 extraction+thermal debinding,the defects of Silicon Nitride balls are effectively controlled.Defect-free Silicon nitride bearing balls with 58.7%green body compactness,3.26 g/cm3 sintering density,99.4%sintering compactness,843 MPa flexure strength are produced.MPIM,holding widespread prospect of application,is an important direction of injection molding technology development in the future.