Microstructure and Isothermal Oxidation of Ir–Rh Spark Plug Electrodes

Zhao, Xia, Xia, Chen, Du, Yang, Liu
2019 Materials  
High-temperature oxidation tests were performed on pure iridium, rhodium, and the iridium alloys, IrRh10, IrRh25, and IrRh40, at 1100 °C in a stable air environment for 60 h. The results of the oxidation were analyzed by X-ray photoelectron spectroscopy (XPS). Microstructural changes of the Ir–Rh alloys were characterized by scanning electron microscopy (SEM). XPS analysis results show that the main oxide of the Ir–Rh alloy in a 1100 °C environment was Rh2O3, and SEM analysis shows that the
more » ... aces of the Ir–Rh alloys after oxidation formed both linear and ellipse-shaped corrosion pits, and had the same direction with the wire-drawing process. The oxidation behavior of Ir–Rh alloys, including the mass change, the reason for the mass loss, and the role of Rh in improving oxidation resistance performance, are discussed.
doi:10.3390/ma12193226 pmid:31581583 pmcid:PMC6804067 fatcat:65l5vneu2jb2hfmahkptgeqhaq