Parameter study of Cr2O3 suspensions for suspension plasma sprayed chromia coatings for wear resistant application

Chromia coatings made by APS are one of the most used ceramic coatings for wear resistant applications. With the aim of achieving superior coating qualities in terms of lower porosities and higher hardness there were a lot of investigations in the past to apply suspension plasma sprayed coatings. A large number of these tests deal with the influence of spray parameters to the coating qualities. In this study, water based chromia suspensions with different physical parameters were used to find out how much the suspension properties influence the coating properties. All tested coatings were made by water based suspensions and sprayed with an Mettech Axial III spray gun. To answer this question, hardness tests, porosity measurements and oscillating ball-on-flat sliding tests were performed. The study show important suspension parameters for high quality wear resistant chromia coatings.