Complex sentence: High temperature parts such as combustors, blades, and vanes in jet engines and stationary gas turbines are increasingly being protected by thin ceramic layers, usually composed of a mixture of zirconia and yttria.
Split into simpler sentences: High temperature parts such as combustors, blades and vanes in jet engines and stationary gas turbines are to an increasing extent being protected by thin ceramic layers. These ceramic layers are usually composed of a mixture of zirconia and yttria.