PREP工艺制造的镍基高温合金粉末中夹杂物

Inclusions in Ni-base superalloy powder by PREP

夹杂物是影响粉末冶金产品质量的主要因素之一。采用SEM、XRD、EPMA等手段通过对等离子旋转电极制粉工艺(PREP)制取的镍基高温合金粉末中夹杂物的形貌特征、化学组成的研究,将不同工序处理后粉末中的夹杂物进行分类,统计分析其存在形式、尺寸、数量及分布。结果表明:粉末中的夹杂物按产生机制和来源主要分为陶瓷、熔渣、有机物、粉末粘连夹杂物或升华物形成的异常颗粒。经过筛分和静电处理后,残留在成品粉末中的陶瓷占夹杂物总数量的7%,熔渣占53%,有机物占40%。筛分和静电分离去除各类夹杂物的能力主要与成品粉末的粒度和夹杂物的密度、介电常数及其尺寸、形态有关。

Inclusion is one of the main factors affecting the quality of powder metallurgy products. Scanning electron microscope（SEM）, X-ray diffraction（XRD） and electron probe microanalysis（EPMA） were used to analyze morphology and composition of inclusions in nickel-base superalloy powder by plasma rotation electrode process（PREP）. Inclusions in powder after different processing were assorted and analyzed their form, size, quantity and distribution statistically. The results show that inclusions in the powder can be divided into ceramics, slag, organic as well as abnormal particles adhering inclusions or sublimate by formation and source. The ceramic accounts for 7% of the residual inclusions in finished powder particles, 53% for slag, 40% for organic. The ability of removing inclusions by screening and electrostatic separation is associated with product particle size range and density, dielectric constant of inclusions, as well as their size and shape.