Complete Maps for the Internal Oxidation of Ideal Ternary Alloys Forming Insoluble Oxides under High Oxidant Pressures

来源期刊：中国腐蚀与防护学报2009年第4期

论文作者：S.WANG Y.NIU F.GESMUNDO

关键词：ternary alloy; high oxidant pressure; internal oxidation map;

摘    要：This paper presents an analysis of the conditions of stability of the different forms of internal oxidation of ideal ternary A-B-C alloys, where A is the most noble and C the most reactive component, forming insoluble oxide and exposed to high pressures of a single oxidant. The treatment, based on an extension to ternary alloys of Wagner's criterion for the transition from internal to external oxidation in binary alloys, allows to predict the existence of three different forms of internal oxidation. In fact, in addition to the most common kinds of internal attack, involving the coupled internal oxidation of B+C beneath external AO scales and the internal oxidation of C beneath external BO scales, a third mode, involving the internal oxidation of C beneath external scales composed of mixtures of AO+BO, becomes also possible under special conditions. A combination of the boundary conditions for the existence of these different types of internal oxidation allows to predict three different kinds of complete maps for the internal oxidation in these systems, one of which involves only two modes, while the other two involve all the three possible modes of internal oxidation.