Oxidation resistant coatings for molybdenum silicide-based composite articles

A method of making a turbine component comprising a molybdenum silicide-based composite and having an environmentally resistant coating disposed on a surface of the molybdenum silicide-based composite, the environmentally resistant coating comprising silicon, titanium, chromium, niobium, and molybdenum, the method comprising the steps of:

• a) providing a molybdenum silicide-based composite substrate formed into the turbine component;
• b) depositing silicon, chromium, titanium, and niobium on the surface of the molybdenum silicide-based composite using a deposition method selected from the group consisting of ion plasma deposition, vacuum plasma spraying, high velocity oxy-fuel spraying, physical vapor deposition, chemical vapor deposition and dipping the molybdenum silicide-based composite into a slurry comprising silicon, chromium, titanium, and niobium;
• and
• c) heat treating the molybdenum silicide-based composite substrate for at least about one hour at a temperature of at least about 1200° C. to form the environmentally resistant coating on the surface of the turbine component, wherein the step of heat treating follows the step of depositing silicon, chromium, titanium, and niobium on the surface of the molybdenum silicide-based composite.