Oxidation of iridium coating on rhenium coated graphite at elevated temperature in stagnated air

• DOI: 10.1016/j.apsusc.2014.12.063
• Publication Date: 2014-12-16T13:06:19Z
• Authors: Yongle Huang; Shuxin Bai; Hong Zhang; Yicong Ye
• Keywords: 0205 materials engineering; 02 engineering and technology; 0210 nano-technology; 3. Good health

Abstract Continuous and dense iridium coatings were prepared on the rhenium coated graphite specimens by electrodeposition. The iridium/rhenium coated graphite (Ir/Re/C) specimens were oxidized at elevated temperatures in stagnated air for 3600 s. The purification of the as-prepared Ir coating was higher than about 99.98% with the main impurity elements Si, Al, Fe and Ru. After oxidation, the Ir/Re/C specimens kept integrity without significant failures and the average oxidation rate was about 0.219 mg/(cm 2 min). Pores were found at the grain boundaries and concentrated to penetrating holes with the growth of Ir grains, which resulted in disastrous failures of the Ir coating.