Ceramic coatings are one solution, but entire blades are quite another. We are generally informed of new happenings by the folks who are attmpting them (Pathfinder, etc) where the press releases contain enough truth to allow publication, and neither reporters or the public know enough to allow balance.
Ceramic blades were tried as far back as Bill Lear and his automotive turbine (I recall watching a 1960ish Chrysler drive by at the NY World's Fair, making a whining sound (like a pilot, but not as loud!)
The need for high temp is the reason, and ceramics love that environment, but they must have great strength to withstand the centripital forces and bending strain as the aerodynamic forces press on them. Nobody has yet found the combination of temperature resistance and strength to beat the metals that turbine blades are made of. But everybody knows how to make a press release.