Research of effect of heat treatment on microhardness and wearing resistance of anodic oxide aluminum coatings modified by nano diamonds

Abstract

Anodizing of aluminum and its alloys is widely used in various fields of science and technology. The process of modifying porous anodic aluminum oxide with ultradispersed diamond (UDD) particles to improve the mechanical characteristics of coatings requires additional study. UDD was modified by consistent heat treatment at 40 °C and 120 °C. The results of the UDD surface modification were controlled by IR spectroscopy. The surface state analysis was carried out using the PMT-3 microhardnessmeter, the SolverPro P47 atomic-force microscope (AFM), and the experimental probe-electrometry device. One of the ways to improve the mechanical characteristics of such coatings is the use of ultradispersed diamonds with respective pretreatment of their surface. The article presents the results of a study of the influence of additives of ultradispersed diamonds with different functional surface composition in an acid electrolyte to form coatings of porous anodic alumina on the surface of AMg-2 aluminum alloy substrates by electrochemical oxidation. An increase in the microhardness and wear resistance of anodic oxide coatings formed on aluminum alloy substrates after various post-growth heat treatments is noted. It is shown that using a combined method based on doping anodic alumina in the process of synthesis with modified ultradispersed diamonds and post-growth annealing of the coatings obtained in vacuum at T = 500 °C, it is possible to obtain a composite material that is 2 times higher in hardness and 3 times higher in wear resistance compared to the initial coating. The research results can be used to create a new generation of radiation-resistant heat-removing bases, nano and micromechanical devices, elements of passive and active electronics, high-quality parts for spacecraft and satellites on modern composite materials.