Nano-Composites NiCrAI (MCrAl) Ternary Alloy Powder Synthesized by Mechanical Alloying

摘要

The purpose of this study was to explore an innovative method for producing nanocrystalline Ni, Cr and Al powders using high energy ball milling and brief secondary processes. Nano-crystalline powders were produced by using a planetary ball mill. The contaminations of the milled metal/alloy powders were carefully avoided by choosing appropriate lining of the vial and the alloy balls. Two approaches were investigated, namely attrition milling of pure metal powders (e.g. Al, Cr and Ni) and mechanical alloying of the elemental powders to form a ternary alloy of NiCrAl. Currently MCrAlY (M=Ni, Co or Fe) powders, up to 40μm in diameter are used in the production of thermal barrier coatings (TBC) on industrial gas turbine components. The powder samples synthesized were characterized by scanning electron microscope (SEM) and transmission microscope (TEM), the crystallite size was found to be less than 20nm; the powder particle size was in the range of 250-300nm; no undesirable particle contamination was detected. It is anticipated that these very fine particles will increase high temperature properties of the thermally sprayed MCrAlY overlay coatings.