Microstructural evolution, oxidation and wear of Al-Cu-Fe quasicrystalline coatings

摘要

Plasma arc sprayed coatings were prepared with two different size fraction starting powders having a nominal composition of Al(sub 63)Cu(sub 25)Fe(sub 12). Powders were obtained by crushing a cast ingot and by gas atomization. Coatings were characterized by electron microscopy, X-ray diffraction and chemical analysis. Oxidation tests were performed in dry oxygen at 500 and 700 C. Finer powders produced coatings with more of the cubic phase than coatings formed with coarser powders. The as-sprayed coatings developed different phases during oxidation. Wear tests of as-sprayed coatings were performed over a range of temperatures in a pin-on-disc arrangement against aluminum oxide. The coefficient of friction increased from around 0.44 at room temperature to near 0.60 at 600 C. Differences in wear behavior of the coatings were seen as a function of temperature.