Study on tribological properties and process optimization of Al2O3-xTiO2 composite coatings prepared by plasma spraying

The grinding roller serves as the pivotal element within a grinding mill, profoundly impacting both the quality of the produced flour and the efficiency of the milling process. A composite ceramic coating composed of Al2O3- xTiO2was applied to white iron substrates utilizing plasma spraying techniques. Comprehensive analyses were performed to examine the coating's microstructural features, mechanical properties, and resistance to wear. Specifically, the study focused on the influence of various plasma spraying parameters-namely, spraying current, spraying distance, and the flow rates of both main and auxiliary gases-on the hardness, bonding strength, and wear resistance of the Al2O3-13TiO2coating. Findings indicate that the Al2O3-xTiO2series coatings exhibit characteristic layered structures typical of plasma-sprayed deposits, with mechanical interlocking occurring between the coating and the substrate. An increase in TiO2 content results in a phase transformation from gamma-Al2O3 to Al2TiO5, enhancing the coating's adhesion strength while simultaneously reducing its hardness and porosity. Additionally, the density of cracks within the cross-section diminishes progressively. The substrate primarily undergoes abrasive and adhesive wear, whereas the Al2O3-3TiO2coating experiences stress-induced fatigue wear. In contrast, coatings with compositions Al2O3-13TiO2, Al2O3-20TiO2, and Al2O3-40TiO2are subjected to strain- induced fatigue wear mechanisms. Optimal plasma spraying parameters, along with the relative significance of each parameter on the overall quality of the coating, were determined through range analysis.