New developments to deposit dense thin ceramic coatings

In the last few years, the number of applications dealing with ceramic coatings has increased very rapidly. At present plasma spraying is considered as a standard way to deposit high performance ceramic coatings for insulation, TBCs, wear and use in the electronics and semiconductor industries. Recently a new thermal spray process and hardware is developed by MEC India to get HVOF-grade high quality thin as well as thick ceramic coatings. Coating properties are better than plasma sprayed ceramic coatings. In thermal spraying, at present high quality thin ceramic coatings are being deposited by suspension plasma spraying (SPS). Our newly developed ceramic coatings are economical than SPS. Surface roughness of as-sprayed ceramic coatings is very low and found to be 2-3 microns only for all ceramics (Al2O3, Al2O3-TiO2, Cr2O3, YSZ). Dense ceramic coatings having porosity level below 2% have been achieved successfully. However, porosity level in the coating can be increased and designed as per application like in TBCs. In this presentation Cr2O3, Al2O3, Al2O3-TiO2 and YSZ coating results and properties are presented and compared with plasma sprayed coatings,respectively. Efforts are being made to improve coating quality, performance and to achieve coatings equivalent or better than SPS at much economical cost.