Mass Transport and Thermodynamics at the Interface in the High-Temperature Metal/Ceramics Composites

金属/陶瓷复合材料是为高温下的结构应用提供的材料。典型材料是用陶瓷涂层、金属颗粒分散陶瓷矩阵复合材料的超合金，以及由陶瓷和金属组成的功能性梯度材料。The interface between ceramics and metals has chemically and mechanically different feature from each bulk material.The object of the present research is that the interface between ceramics and metals is generalized as a basis of the thermodynamics and transport phenomena to discuss the chemical stability of the interface。两个不同的主题被广泛地概括为相互现象。其中之一是对热动力学特性和复合氧化物的扩散作用的衡量，其中产品在界面上是一个问题。另一种是氧化物陶瓷和金属之间的高温度氧化。（1）复合氧化物Pe的热动力学性质和复合氧化物Pe的混合作用 ... More rovskite type chromites （ABO D23-D2） are focused in the present work。They have important role at the interface between Cry D22-D2O-D23-D2 scale and？y to improve the scale adhesion。With respect to the thermodynamic properties， the standard Gibbs energy change of formation， ΔG°， on NdCrOイイD23イイD2 was determined by measuring the electroconductivities of the different two-phase samples， NdCrOイD23イイD2 with CrイD22イイD22イD2OイD23イD2 and NdイD2。As compared with the reported ones of YCrO·D23·D2 and LaCrO·D23·D2， the value of？G°is consistent in the relationship between？G°and ionic radius of A ion。Diffusion coefficients of A ions in LaCrO·D23·D2 and NdCrO·D23·D2 was determined by the solid state reaction technique。Discussed their diffusion coefficients with the reported value of Y ion in YCrO D23 y D2， the absolute values can be plained with the concentration of A site vacancy。激活能量取决于A离子的离子半径，按顺序与他们的染色体，在BaTio-D23-D2也是用相同的方法衡量的。The values of BaTiOイD23エD2 is very similar to their chromites。Perovskite氧化物中的离子的扩散系数对A和Bion的价值有一点依赖。（2）Htemperature oxidation at the interface between oxide？amics and metals？idation of Ni covered by YイD22·イD2O·イD23·イD2·イD2 （YSZ） is investigated in this work。The one dimensional model of the oxidation kinetics is established to assume that flux of O-D12-YSZ is equal to one of Ni-D12+ Y-D1 in the NiO scale。按顺序验证动力学模型、氧化率和氧化物部分压力，对界面对YSZ薄板包括镍在内的近细胞进行调查。实验结果与动力学模型达成了一致。陶瓷涂层在金属和金属粒子分散上界面的生命设计陶瓷矩阵复合体可以作为动力学模型的一个基础。Less（低）

Metals/ceramics composites are the promising materials for structure application at high temperatures. Typical materials are superalloys with ceramic coatings, metallic particles dispersion ceramic matrix composites, and functionally gradual materials comprised of ceramics and metals. The interface between ceramics and metals has chemically and mechanically different feature from each bulk material.The objective of the present research is that the interface between ceramics and metals is generalized as a basis of the thermodynamics and transport phenomena to discuss the chemical stability of the interface. Two different topics are carried out to generalize the interfacial phenomena. One is the measurements of thermodynamic properties and diffusion coefficient of the complex oxides which are the products at the interface. Another is high temperature oxidation at the interface between oxide ceramics and metals.(1) Thermodynamic properties and diffusion coefficient of the complex oxidesPe … More rovskite type chromites (ABOィイD23ィエD2) are focused in the present work. They have important role at the interface between CrィイD22ィエD2OィイD23ィエD2 scale and alloy to improve the scale adhesion. With respect to the thermodynamic properties, the standard Gibbs energy change of formation, ΔG°, on NdCrOィイD23ィエD2 was determined by measuring the electroconductivities of the different two-phase samples, NdCrOィイD23ィエD2 with CrィイD22ィエD2OィイD22ィエD2 and NdィイD22ィエD2OィイD23ィエD2. As compared with the reported ones of YCrOィイD23ィエD2 and LaCrOィイD23ィエD2, the value of ΔG°is consistent in the relationship between ΔG°and ionic radius of A ion.Diffusion coefficients of A ions in LaCrOィイD23ィエD2 and NdCrOィイD23ィエD2 was determined by the solid state reaction technique. Discussed their diffusion coefficients with the reported value of Y ion in YCrOィイD23ィエD2, the absolute values can be explained with the concentration of A site vacancy. The activation energy depends on the ionic radius of A ions.In order to compare with their chromites, diffusion coefficient of Ba ion in BaTiOィイD23ィエD2 is also measured by the same method. The values of BaTiOィイD23ィエD2 is very similar to their chromites. Diffusion coefficient of A ion in the perovskite oxides has little dependence of the valances of A and B ions.(2) High temperature oxidation at the interface between oxide ceramics and metalsOxidation of Ni covered by YィイD22ィエD2OィイD23ィエD2-stabilized ZrOィイD22ィエD2 (YSZ) is investigated in this work. The one dimensional model of the oxidation kinetics is established to assume that flux of OィイD12-ィエD1 in YSZ is equal to one of NiィイD12+ィエD1 in the NiO scale. In order to verify the kinetic model, the oxidation rate and oxygen partial pressure at the interface were investigated on the close cell with YSZ thin plate including Ni in the inside. The experimental results are in agreement with the kinetic model. The life design of the interface of the ceramic coating on the metals and metal particle dispersion ceramics matrix composite can be enable as a basis of the kinetic model. Less