INVESTIGATION OF THE WEAR CHARACTERISTICS OF THERMAL BARRIER COATING IN A BIODIESEL ENGINE

Abstract

This study applied piston-valve coating for an engine that worked 100% on biodiesel fuel and investigated the wear characteristics after the experiment. The plasma spraying method was used as the coating method. Al2O3 and ZrO2 ceramics, which are the most frequently used ones in the literature, were selected as coating material. The deformations on the coated and uncoated surfaces were determined after running the engine at different time intervals. The deformations on the piston surfaces were interpreted by conducting SEM and EDX analyses. In particular, the deformation on the coating material, thermal fatigue cracks, abrasive wear and elements that clang to the piston surface after combustion were determined. Additionally, post-combustion engine oil analysis was carried out to determine the elements that were released as a result of the thermal wear in connection to combustion. The relationship of the coating with thermal efficiency was investigated for all types of coatings by determining temperatures from a certain point on the engine by using a thermal camera and a surface temperature measurement device. As a result of the SEM, EDX and engine oil (ICP) analyses, it was seen that the elements that are released as a result of wear such as Al, Fe and Cr had lower quantities with the aluminum oxide (Al2O3) coating with the Nickel–Chromium (Ni–Cr) bonding agent in comparison to the other coating materials. Additionally, as a result of oil analyses, the coated engine was observed to have more positive outcomes in comparison to the uncoated engine.