Preparation of alpha-Al2O3 base ceramic coating on aluminum alloy via thermo-decomposition of diaspore

The aim of this work is to describe the possibilities of preparing a corund um coating on aluminum alloy through in-situ chemical reaction at a relativ e low temperature. The transformation conditions of diaspore (beta -AlOOH) to corundum (alpha -Al2O3) are studied using X-ray diffraction analysis. Te mperature and heating time are two main factors influencing the transformat ion. Suitable heating parameters can lower the transformation temperature. On this basis, a new process is developed to produce corundum ceramic coati ng on an aluminum alloy substrate. The phase composition and microstructure of the coating are studied using X-ray diffraction analysis and Scanning E lectron Microscopy. Abrasion properties of the coating are evaluated by rin g-block tri-botester, The results show that it is feasible to obtain cerami c coatings on aluminum alloy substrates by means of thermo-decomposition of diaspore.