The Influence of the Phase Arrangement of ATZ Composites on Their Wear Rate Under Ball-on-Disc Tests

An alumina-toughened zirconia (ATZ) material, fabricated using a procedure consisting of the common sintering of two different zirconia powders, was tested using the ball-on-disc method in a temperature range between 20 and 400 °C. Tetragonal zirconia balls were used as a counterpart. Three different types of microstructure were designed, one consisting in separated alumina inclusions in zirconia matrix, the second one containing alumina inclusion in the amount close to the percolation point and another one which was a combination of two continuous phases, penetrating the whole volume of the composite. It was detected that at elevated temperatures all materials showed distinct decrease of measured wear rate. Composite with a low alumina content showed minimal wear rate at 300 °C and composites with higher amount of alumina were the most wear resistant at 400 °C. There are some evidences that this minimal wear rate is connected with a pseudoplastic behavior of a layer formed between co operating elements of tribological pair.