The synthesis of NiCrAlHf powders with mechanical alloying method for thermal sprayed coating

Abstract

NiCrAl is a material commonly used for coating in order to increase corrosion or oxidation resistance of materials applied at high temperatures. The addition of hafnium (Hf) as reactive elements to NiCrAl coating are found to prolong the life of the industrial gas turbine blade and increase its performance. NiCrAlHf powders used as the base material were mixed using planetary mill device for 36 hours with a speed of 25 Hz or 1500 rpm. Characterization of NiCrAlHf powder was investigated before and after milling process using Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The results showed that the synthesized powders were agglomerated. The obtained particle size of 9.64 µm, 19.97 µm, 39.27 µm, 19.93 µm, and 22.8 µm was observed before milling process, after 9, 18, 27, and 36 hours milling process, resepectively. The phase formed on the synthesized NiCrAlHf powder after 36 hours milling process included Ni and Cr with crystallite size of Ni 25.4 nm and Cr 8.8 nm calculated by Scherrer method. In addition the peak profile of the Al phase gets more amorphous after 27 hours.