Mechanical properties, microstructure and wear characteristic of abradable material coated by HVOF with variation of surface treatment and spray distance

The Abradable material coating has been widely applied to protect metal component from severe wear problem. This research is focused on coating ST-37 steel using abradable brake lining material by adding copper conductive material as heat conductor material using the HVOF coating method. Application of HVOF method for abradable material coating is rarely found, however it has potential for this application since the method can produce thick and dense coating layer. This research was conducted by varying the spraying distance of 20, 30, and 40 cm and variation of surface treatment to vary the surface roughness of substrate. Among characterization performed after the coating are wear test, microstructure, hardness, and SEM characterization. Based on the data obtained from the study, it was found that the abradable material layer resulting from the surface treatment of blasting etching with a spray distance of 20 cm has the most optimal value in terms of the least amount of porosity in coatings with ST-37 steel, the highest value of coating hardness of 468.2 HV_{0,5 kgf}, the thickest average layer with an average value of 132.36 µm, and the lowest mass reduction of 0.00148 mg. For wear characteristics it is found that all layers with surface treatment and spraying distance have abrasive wear characterized by plowing or fragmentation.