Micro-structural study and wear resistance of thermal barrier coating reinforced by alumina whisker

The present study describes the experimental results regarding the effect of the addition of ceramic whisker, on the microstructural and friction property of plasma sprayed yttria-stabilized zirconia coating sprayed on an Inconel substrate with optimized process parameters. To deposit a bond layer between the ceramic top coat and substrate surface, all samples have coated with the metallic intermediate NiCrAlY bond coat. For the micro structural study, the powders/coatings morphology and wear marks on YSZ coated were investigated by a Field Emission Scanning Electron Microscopy and Energy Dispersive X-ray analysis (FE-SEM/EDS). The mass loss, wear resistance and coefficient of friction of the YSZ top coat against Alumina Ball were tested with a ball-on disc wear testing at loads of 7,10 and 13 N. The results showed that reinforced coating gives a higher wear resistance compared to the conventional coating without changing the friction coefficient. The improvement in wear resistance of the ceramic whisker reinforced coatings could be mainly due to the interlocking interface between splats and decrease of intralamellar cracks in the top coat. The wear mechanisms of reinforced and unreinforced TBC were discussed in terms of exfoliation and degradation wear mechanisms.