| Catalytic combustion of methane is one of the most promising processes to produce environmentally clean energy. Metallic monolithic catalyst possesses several advantages over others. However, the development of metallic monolithic catalyst is prevented by the poor adhesion of the oxide (active component and inter layer component) with the alloy. This dissertation is based on the mechanical properties of the alloy to study the fitting interface conditions between the alloy and the oxide, to study the factors having influence on the peeling off of the oxide layer, and to propose a model which is used to describe the peeling off of the oxide layer. At last, the model is extended to describe the peeling off of activity component.The ductile-to-brittle transition temperature (DBTT) of the FeCrAlloy has effect on the thermal stability of the metallic monolithic catalyst. The FeCrAlloy is oxidized at different temperatures and is measured by a tensile test at room temperature. The DBTT of it is confirmed to be 650 oC by the analysis of the mechanical properties change. The dynamic elastic modulus of it is measured by the Dynamic Mechanical Analysis (DMA). The dynamic elastic modulus has an increase peak at about 300 oC, which is due to the diffusion of the Cr atoms from the body of the alloy to its surface. After the peak, the dynamic elastic modulus decrease rapidly and linearly with rising temperature. After oxidized at 1100 oC, the damp of the FeCrAlloy fluctuates between 450-550 oC due to the decrease of residual stress of the oxide. The residual stress of the oxide can be relaxed because the elastic modulus of the FeCrAlloy becomes smaller and smaller above 460℃.The residual stress of the oxide is measured by the XRD technique. The oxide layer is in the condition of compressed stress under cooling. The residual stress of the oxide layer is the largest when the FeCrAlloy is under 600 oC thermal cycle while it is the smallest under 800 oC thermal cycle. As the DBTT of the FeCrAlloy is 650 oC, the plasticity of the FeCrAlloy at high temperature can reduce the residual stress of the oxide layer.There are some advantages using the acid solution to pre-treat the FeCrAlloy before being oxidized at high temperature. Firstly, after the acid treatment, the FeCrAlloy has good oxidation resistance ability which can prolong the catalyst life. Secondly, the FeCrAlloy has good thermal shock resistance ability which can decrease the peeling off of the oxide layer. Thirdly, the oxide layer has some cavities and holes which benefits the activity component to adhere to the support easily.The thermal shock test is used to study the mechanical properties of the FeCrAlloy. The results show that the weight loss of the FeCrAlloy under 600 oC thermal shock is the largest, that under 500 oC and 700 oC are much smaller, and that under 800 oC is the smallest. The oxide peels off the interface between the alloy and the oxide layer. After the thermal shock, the strength of the FeCrAlloy is measured by the tensile test. The results of the tensile test show that the strength of the FeCrAlloy under 600 oC thermal shock is the smallest, while that under 500 oC, 700 oC and 800 oC. are much larger. After the tensile test, the FeCrAlloy is oxidized at 1100 oC. The result shows that the oxidation rate of the FeCrAlloy which is under 600 oC thermal shock is the largest, the following is that under 500 oC, 700 oC and 800 oC.A model for the peeling off of the oxide layer during cyclic thermal shock is proposed. It is supposed that the strain energy at the interface of the alloy and the oxide layer is a function of the times of cyclic heating and cooling. The peeling off of the oxide layer is a function of its stress and the stress is proposed as a function of the times of cyclic heating and cooling. This model is valid according to the experiments. Then the model is extended to describe the peeling off of the activity component from the FeCrAlloy support. The results also show us the validity of the model.
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