Coating of Al 5052 alloy by adding different additives by micro arc oxidation method and investigation of tribological properties at high temperature

In this study, coating process was applied to the surface of Al 5052 alloy by micro arc oxidation method. Four different electrolyte solutions were prepared by adding graphite, hexagonal boron nitride, zinc oxide particles to the existing electrolyte, especially the alkaline electrolyte. The surface properties of the samples after coating and their tribological behavior at high temperatures were studied. The surface roughness values of the samples increased after coating and were obtained as 8,82 µm in the lowest graphite doped sample. The coating thickness values varied with different electrolyte types and the highest was found in the zinc oxide doped sample as 230,1 µm and the lowest was found in the graphite doped sample as 118,5 µm. From the XRD analysis of the samples Al, γ-Al2O3 and α-Al2O3 phases were detected in addition to the existing contributions in the structure. The average por size and por number were observed in the least graphite-doped sample. In friction and wear experiments conducted at room temperature (25 ºC) and high temperatures (90, 150 and 250 ºC), the average friction coefficients of the samples decreased with increasing temperature, and the specific wear rates increased. The lowest coefficient of friction and wear rate at all temperatures occurred in the graphite doped sample, these values were determined in the ranges of 0,25-0,35 and 1,495x10-2 - 2,185x10-2 mm3/(N.m) respectively. Key Words: Micro arc oxidation, Al 5052, Graphite, h-BN, ZnO, Wear