Evaluation of tribological property and coating reliability of alumina and aluminum silicate-coated A356 aluminum alloy

Material loss due to relative motion between the contact surfaces causes surface degradation leading to premature failure of engineering systems. Of the several techniques to improve the wear resistance of rubbing components, the process of providing a hard protective surface coating has gained tremendous significance. Aluminum alloys used in engineering applications are exposed to rubbing, resulting in progressive wear. Sol-gel coating is a widely accepted surface coating technique for aluminum alloys, and this paper focuses on alumina and aluminum silicate coating applied to aluminum alloys. The tribological characteristics such as coefficient of friction (COF) and volumetric wear losses (VWL) are evaluated using a pin on disc (POD) tribometer. Finite-element analysis (FEA) plays a vital role in bringing an approximate solution to various engineering and non-engineering problems. The POD tribometer is modelled in the design modeller of the Ansys workbench based on the Archard wear model. The coating reliability is experimentally estimated based on its tribological properties. Surface hardness is measured by microhardness indentation test, and materials characterization is done using atomic force microscopy (AFM) and Fourier transform infrared radiation (FTIR) spectroscopy. It is observed that alumina coating exhibits better tribological properties than aluminum silicate-coated A356 aluminum alloy.