| abstract |
Coatings that provide substantial oxidation protection for titanium substrates are comprised of a continuous coating of ductile MCrAl or ductile MCr alloys where M is at least one metal selected from the group consisting of iron, nickel, and cobalt. Ductile MCrAl alloys are comprised of, by weight percent: about 10 to 40 percent chromium, about 4 to 10 percent aluminum, and the balance substantially iron; about 8 to 40 percent chromium, about 4 to 10 percent aluminum, and the balance substantially nickel; or about 10 to 25 percent chromium, about 4 to 5.5 percent aluminum, and the balance substantially cobalt. Ductile MCr alloys are comprised of, by weight percent: about 20 to 40 percent chromium, and the balance substantially iron; about 20 to 50 percent chromium, and the balance substantially nickel; or about 15 to 35 percent chromium, and the balance substantially cobalt. Adhesion promoting elements such as Zr, Si, Ta, Hf, Y, Sc, or La may be present in the MCrAl or MCr alloys. The coatings can be deposited by plasma spraying, chemical vapor deposition, or physical vapor deposition and remain adherent on titanium substrates during repeated thermal cycling while providing substantial oxidation protection up to about 950 DEG C. |