Abstract
Protective coating is an indispensable technology of a gas turbine plant. High velocity oxygen-fuel (HVOF) spray is one of the coating processes. High temperature mechanical properties of thin protective coating have not been clarified because of the difficulty in measurement. The purpose of this study is evaluation of the high temperature mechanical properties of the protective coating. Lateral compression test for the circular tube coatings of HVOF-sprayed thin coating under various temperature conditions were carried out. Results are summarized as follows. (1) Young's modulus and bending strength decreased with an increase of temperature. Young's modulus suddenly dropped around 500℃. Bending strength suddenly dropped around 450℃. (2) The heat-treatment at the high temperature, such as 1100℃, is effective for the improvement of the mechanical property, such as Young's modulus and bending strength and fracture strain. (3) Atmospheric heat-treatment is effective for the improvement of Young's modulus and bending strength. Vacant heat-treatment is effective for the improvement of fracture strain.
