Crystallite size, microstrain, and microhardness analysis of NiCrAlX coating

The present study analyzed crystallite size, microstrain, and microhardness of NiCrAlX coating before and after oxidation. NiCrAl is a precursor material and X is a reactive element. Two types of reactive elements were added such as silicon and yttria. The oxidation test was exposed at a temperature of 1000 oC for 100 h. To understand the characteristic of the coating materials, NiCrAl powders with and without the addition of reactive elements were analyzed. The crystallite size, microstrain, and dislocation density were measured using Scherrer’s equation. The milled powder showed a decrement of crystallite size up to 30 µm which caused the increment of microstrain and dislocation density. After the oxidation test, the increment of crystallite size, microstrain, and dislocation density was showed on NiCrAl and NiCrAlSi. Meanwhile, NiCrAlY showed a decrement of microstrain and dislocation density. It was supported by the biggest hardness value of NiCrAlY after the oxidation test than the other coating samples. It indicated that the mechanical properties were improved, thus obtained a good performance of the coating system.