Evaluation of wear damage in zirconia plasma-sprayed coatings using scanning white light interferometry

The mechanical and tribological properties of thermal barrier coatings (TBC s) can be improved by means of a thermal treatment. The evolution of the me chanical and tribological properties in a NiCr-ZrO2 TBC with different time s of thermal treatment has been measured. In this work, scanning white ligh t interferometry (SWLI) is used to observe and quantify the ZrO2 wear damag e. ZrO2 shows very poor light reflection, and a sputtering process over the coating has been made to achieve a proper light reflection and make the us e of SWLI possible. It has been observed that thermal treatments at 1000 degreesC produce a dec rease of the wear damage and an increase of hardness, The ball-on-disk test and the wear mechanisms are described and include the intersplat delaminat ion of the main wear process in the as-sprayed coatings and thermally treat ed samples. The volume loss after 18 h at 1000 degreesC is 38% less than th e as-sprayed coating. The erosion test and hardness measures show the same evolution as the ball-on-disk test.