OF WC-Co HVOF THERMAL SPRAY COATING: EFFECTS OF COATINGTHICKNESS. This research investigated the characteristics of HVOF (High Velocity Oxy-Fuel) thermal spray WC.Cocoating to be applied on the nozzle of RX-1 00 rocket as the substitute for the massive graphite currently in use. One aspectthat determines the performance ofHVOF coating is the thickness, so this work studied the effects of coating thickness on themechanical properties and microstructures of the coating. Mechanical characterization was conducted as well as microstructuralevaluation by using optical microscope and Scanning Electron Microscope (SEM). The results showed that the coatingthickness was getting further from the target as the number of passes increases. It is noteworthy that the highest microhardness,619 VHN, was possessed by the thinnest WC-Co coating, which was 175 11m. No quantitative results on the bonding strellgthof the coating was obtained due to the lower strength of the adhesive. Microstructural analysis of the WC-Co coating showedthat this coating is relatively dense with variety in chemical content on different area. An indication of diffusion of W in theinterfacial area was found, which is thought to contribute to the high strength of the coating.Key words: HVOF (High Velocity Oxy-Fuel), thermal spray, WC-Co, grit blasting, coating thickness. Bondan T. Sofyanl, Haposan J. Pardedel, Marizki Stefano dan Edi Sofyan, I Departemen Metalurgi clan Material, FT -VI, Kampus VI, Depok 164242Pusat Teknologi Dirgantara, LAPAN
