Open AccessHigh temperature treatment effects on the microstructure and properties of a plasma sprayed 25 mol% AI2O3-25 mol% Cr2O3-50 mol% TiO2 coating
Author(s) -
Maximilian Grimm,
Susan Conze,
L.M. Berger,
Rico Drehmann,
Thomas Lampke
Publication year - 2021
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/1147/1/012029
Subject(s) - materials science , microstructure , coating , titanium , porosity , atmospheric pressure plasma , mole , zirconium , sintering , delamination (geology) , composite material , metallurgy , plasma , chemistry , biochemistry , physics , quantum mechanics , paleontology , biology , subduction , tectonics
In this study, the influence of heat treatments up to 1200°C in vacuum on coatings prepared by atmospheric plasma spraying (APS) from a blend of 25 mol% Al 2 O 3 , 25 mol% Cr 2 O 3 and 50 mol% TiO 2 on microstructure, porosity, hardness and sliding wear resistance was investigated. The well-known transformation from α-Al 2 O 3 to γ-Al 2 O 3 occurred as a result of the spray process, as well as small amounts of titanium were found in Cr 2 O 3 splats due to an interaction between the feedstock particles. No significant changes were found after a heat treatment at 400°C or 800°C. Heat treatment at 1200 °C led to complete coating delamination. Besides the retransformation of γ-Al 2 O 3 to α-Al 2 O 3 , interactions between Cr 2 O 3 and TiO 2 splats and the formation of CrTi 2 O 5 was observed. The formation of Al 2 Ti 7 O 15 was observed in result of a reaction at the outer regions of the Al2O3 splats. At the same time, a reduction in porosity and healing of microcracks were observed as a result of sintering processes, which leads to an increase of the coating hardness to 1170 HV0.2.