Comparison of flame sprayed Al2O3/TiO2 coatings: Their microstructure, mechanical properties and tribology behavior

In this paper the porosity, phases, mechanical properties and abrasive wear resistance of ceramic layers of Al2O3/TiO2 deposited by flame spray process were evaluated. The percentage of titania has a strong influence on the coatings porosity, as shown by the fact that with increasing titania content porosity will be reduced. The crystalline phases of the deposited layers changed according to the characteristics of the powder and the thermal process employed. While hardness depends only on the percentage of titania content, in the studied range, toughness depends on several factors, such as hardness, porosity and intergranular precipitation. The resistance to abrasive wear depends almost exclusively on the hardness of the coating.