Oxidation resistant coatings for niobium-based silicide composites

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

• a) providing a niobium-based refractory metal intermetallic composite substrate formed into the turbine component, wherein the niobium-based refractory metal intermetallic composite comprises one of:
• i)between about 19 atomic percent and about 24 atomic percent titanium, between about 1 atomic percent and about 5 atomic percent hafnium, between about 11 and about 22 atomic percent silicon, between about 5 and about 14 atomic percent chromium, and a balance of niobium;
• and
• ii)between about 19 and about 24 atomic percent titanium;
• between about 1 and about 5 atomic percent hafnium;
• up to about 7 atomic percent tantalum;
• between about 11 and about 22 atomic percent silicon;
• up to about 6 atomic percent germanium;
• up to about 12 atomic percent boron;
• between about 5 and about 14 atomic percent chromium;
• up to about 4 atomic percent iron;
• up to about 4 atomic percent aluminum;
• up to about 3 atomic percent tin;
• up to about 3 atomic percent tungsten;
• up to about 3 atomic percent molybdenum;
• and a balance of niobium;
• and
• b) depositing the environmentally resistant coating onto the surface of the component.