The Environmental Barrier Coating of CMC blades is similar to Thermal Barrier Coating applied in Ni Superalloys. Film cooling is over and above that. I remember reading that they are skipping film cooling in CMC blades (don't remember the reason why). So I was saying that the film cooling is missing, not the coating.
They might be used in XF9 engines for vanes or other stationary parts. They are also used in CFM-56 LEAP engines. But never before have they been used in turbines.
Maybe stationary components are able to handle 2000 degrees. In rotating components (turbines), creep resistance becomes more important. So same material that can withstand 2000 degrees as a turbine shroud, for example, will be rated at 1800 degrees as a turbine blade material.
GoI is content with GE engines for now and want to spend all money on JV for AMCA engines. Well, its not like GTRE is sitting idle either. But they are underfunded and out of time. They are also focusing on dry version of Kaveri for UCAV. Not sure if they are still trying to solve the reheat oscillation problem given their limited time, funding, facilities and manpower.
My bad. I meant 2035, not 2025.
I don't think there is any plan yet for the engine, but I would be delighted if they can get it done in time for AMCA Mk2 which has deadline of 2035.