The effect of water vapor on the oxidation behavior of Ni–Pt–Al coatings and alloys

• Published in: Surface & coatings technology Vol. 201; no. 7; pp. 3852 - 3856
• Main Authors: Pint, B.A., Haynes, J.A., Zhang, Y., More, K.L., Wright, I.G.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 20-12-2006; Elsevier
• Subjects: Aluminum oxide; Applied sciences; Chemical vapor deposition; Corrosion; Corrosion environments; Exact sciences and technology; High temperature oxidation; Metals. Metallurgy; Platinum; TEM; Water vapor; Water vapor; Platinum; Chemical vapor deposition; TEM; High temperature oxidation; Aluminum oxide; Aluminium oxide; Plasma; Temperature; High temperature; Coatings; Surface treatment; Vapor deposition; Transmission electron microscopy; Chemical deposition; Oxidation; High temperature corrosion
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2006.07.244

Turbines fired with hydrogen or syngas from coal gasification will have significantly higher water vapor contents in the combustion gas than natural gas fired turbines. The effect of increased water vapor on alumina-forming coatings and model alloys was investigated at 1100 °C in furnace cyclic testing. Increasing the water vapor content from 10% to 50 vol.% increased the amount of scale spallation on undoped alumina-forming alloys. Compared to dry O
2, increased spallation was observed for β and γ/γ' phase coatings on the substrates of alloys 142 and N5. In all cases, the addition of water vapor appeared to reduce the formation of alumina whiskers and ridges at the scale–gas interface, but did not significantly change the alumina growth rate. The addition of water vapor may have a detrimental effect on the selective oxidation of Al in γ/γ' alloys and coatings.