Study of brake disklets by HVOF Method and investigation on brake performance in vehicles

In this study; ıt has been worked on brake discs used in passenger cars. The behavior of these discs in the braking order, the wear performance of the braking process of the coated and uncoated surfaces was evaluated. CoNiCrAlY ceramics powder, WC-Co (88/12) ceramic powder, NiCrBSi ceramic powder and MoNiCrBSiFe(Mo% 25) ceramic powder were coated on the surfaces of commercially produced discs with HVOF (High Velocity Oxy-Fuel) coating method. Coating process was made by 1 mm thickness Plasma Technical Hard Metal and Ceramic Coating C.O. The abrasion process of the coated and uncoated discs was evaluated according to the test results which were repeated 20 times with a time interval of 15 seconds in the brake test device in Automotive Engineering Application and Research Laboratory. In the brake test made, the surface roughnesses of the discs, the weights, the temperatures and the wear values on the disc surfaces were determined depending on the brake forces applied to the discs during the test. The highest wear on the discs was found in the CoNiCrAlY ceramic dust coated disc with 0.4 grams, while the minimum wear was found to be on the disc coated with NiCrBSi ceramic dust with a minimum of 0.2 grams. After the brake tests were finished, samples were cut from the disks used in the experiment by CNC machine and SEM (Scanning Electron Microscope) microstructure images were taken. When the microstructures of the samples were examined, it was observed that the ceramic powders used formed a good bond with the brake disc. After the microstructure studies, the thermal conductivities of each of the samples were determined. Hardness values of coating thickness of coated discs were compared by micro hardness method. Corrosion behaviors of the discs used in the study were investigated and the experimental results were discussed.