ANALYSIS OF THE THERMAL SHOCK AND FOULING RESISTANCE OF THE KALIMANTAN ZIRCON BASED HYBRID COMPOSITE CERAMIC COATING IN BOILER ENVIRONMENT

Power plant boilers operate at relatively high temperatures and pressures. As they are prone to material degradation, fouling and scaling, the materials used must have good thermal and chemical resistance. Coating material is one of the solutions to problems that exist in boilers. In this study, the basic coating material used came from local mineral resources, namely Kalimantan zircon sand and zirconia that had been purified from zircon sand. And there is the addition of filler as a coating reinforcement so that the coating properties become better. The variables of this study are variations of filler materials that have lubricating properties such as hBN, MoS2, graphite and a mixture of the three fillers (hybrid). The coating method used is slurry spray coating and then sintering at 600 °C. The main coating parameter tests carried out were thermal shock and anti-fouling resistance. From the research results, it was found that the purification of zircon sand resulted in an increase in Zirconia content from 59 % to 68 %. From the results of the thermal shock resistance and anti-fouling tests, it was found that the coating with purified zircon has better thermal shock resistance while the fouling resistance is not significantly different from unrefined zircon sand, so it is necessary to develop a zircon purification process to obtain a higher ZrO2 content. For filler variations, the hybrid filler produces a coating with better thermal shock and anti-fouling resistance so that it can be used for optimizing ceramic composite coatings.