Gas turbine blade

Gas turbine blades have a ceramic thermal insulation layer of 10-95 wt.% magnesium aluminate (MgAl2O4), 5-90 wt.% magnesium oxide (MgO) and 0-20 wt.% aluminum oxide (Al2O3), rest usual impurities. It has MgO grains with an average diameter of 0.1-10 mu m embedded in a matrix of MgAl2O4 spinel. The layer has a porosity of over 3 vol.%.