Properties of Al2O3/TiO2 and ZrO2/CaO flame-sprayed coatings

The article presents the results of a study on the exploitation properties of flame-sprayed ceramic coatings produced from an oxide ceramic material in the form of powder based on an aluminum oxide (Al2O3) matrix with an addition of 3 % titanium oxide (TiO2) and also on a zirconium oxide (ZrO2) matrix with 30 % of calcium oxide (CaO) on a substrate of unalloyed structural steel of grade S235JR.The buffer layer was produced from a metallic powder on the basis of Ni-Al-Mo.Plates with dimensions of (5 × 200 × 300) mm and also the front surfaces of f40 × 50 mm cylinders were flame-sprayed.The buffer coatings were produced using a RotoTec 80 torch and external specific coatings were produced with a CastoDyn DS 8000 torch.Investigations of the coating properties were based on metallography tests, a phase-composition research, a measurement of microhardness, a research of the coating adhesion to the substrate, the abrasive-wear resistance (acc.to ASTM G65 standard), the erosion-wear resistance (acc.to ASTM G76-95 standard) and a thermal-stroke study.The coatings were characterized by a high adhesion to the substrate and also high erosion and abrasive-wear resistance and the resistance to cyclic thermal strokes.