Abstract
In waste-to-energy power generation plants, increasing the combustion temperature improves plant efficiency. However, due to problems caused by molten chloride corrosion, the combustion temperature cannot be increased. Consequently, in order to increase the temperature, it is first necessary to protect components from molten chloride corrosion. In this study, CoNiCrAlY coating is proposed as a protective film against molten chloride corrosion. Three kinds of specimens were prepared. One was standard coating made from conventional CoNiCrAlY. The others included the addition of Mo to the CoNiCrAlY by two different techniques. One technique is mechanical alloying (MA), and the other is a gas-atomizing technique. The mechanic-chemical reaction that occurs during the mechanical alloying process can be expected to create new functionality for the material. The effect of Mo content was evaluated for corrosion resistance. These specimens were coated by low pressure plasma spraying (LPPS). The specimens were exposed to NaCl-KCl for the molten chloride corrosion test. The results of the corrosion tests show that corrosion resistance improved in only MA CoNiCrAlY coatings. These results reveal that mechanically alloyed CoNiCrAlY-Mo coating has excellent corrosion resistance, and its corrosion resistance behavior is different from that of gas-atomized CoNiCrAlY-Mo.
