石墨对粉末冶金镍基高温合金氧化行为的影响研究

Effect of graphite on oxidation behaviors of powder metallurgy nickel-based superalloy

用粉末冶金热压制备了不含石墨以及添加了3%石墨的镍铬基合金,考察两种合金在900℃时的等温氧化行为,用扫描电镜(SEM)和X射线衍射仪(XRD)分析材料的氧化产物。结果表明,不含石墨时,合金表面氧化生成尖晶石结构的NiCr2O4以及Cr2O3,从而抑制了材料的氧化速度。加入石墨后,由于石墨的氧化分解,在材料表面生成了疏松的Cr2O3,使材料的氧化增重增加。

Nickel-based alloys with different graphite contents were prepared by powder metallurgy method. The isothermal oxidation behavior of the nickel-based alloys was investigated at 900 ℃. Oxidized alloys were characterized by SEM and XRD. The results showed that the alloy without graphite showed a lower mass gain than that of the alloy with graphite at 900 ℃ exposure. Surface examination indicated that the alloy without graphite possessed oxidation resistance due to the NiCr2O4 and Cr2O3 formation on the surface, the oxidation mass gain of the alloy with graphite increased because the oxide decomposed, and loosed Cr2O3 formed on the surface.