Theoretical consideration on composite oxide scales and coatings

• Published in: Journal of rare earths Vol. 31; no. 5; pp. 435 - 440
• Main Author: 何业东 高唯
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2013
• Subjects: Alloys; Aluminum oxide; Coatings; composite oxide coatings; composite oxide scales; high-temperature oxidation of alloys; Oxides; Rare earth metals; rare earth oxides; Scale (corrosion); Sealing; Seals; Zirconium dioxide; 复合氧化膜; 复合涂层; 密封机构; 机械特性; 涂料保护; 热力学条件; 热膨胀系数; 高温氧化; high-temperature oxidation of alloys; rare earth oxides; composite oxide scales; composite oxide coatings
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/S1002-0721(12)60300-7

The present paper discussed some fundamental aspects on composite oxide scales and coatings for protection of alloys from high temperature oxidation, the related thermodynamic conditions, special mechanical characteristics and a sealing mechanism. It was proposed that the oxide scales and coatings with a composite structure should possess superior mechanical properties than that with a single phase oxide. It also showed that the A1203 scales or coatings doped with 3（203 and ZrO2 （or YSZ）-A1203 composite coatings possessed superior properties at high temperatures. In such composite oxide scales and coatings, the fracture resistance of the scales was increased by the toughening effect, the thermal stress was decreased owing to the increase of thermal-expansion coefficients, and A1203 phase could seal the alloy substrate well In addition, the kinetic equation of thermal growth oxide on alloy covered with composite oxide coatings was derived.