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随着冷启动排放问题的日益严重,金属载体催化剂除了应用于摩托车和柴油机尾气催化燃烧外,不久将用于密耦型催化剂。然而,金属载体与活性涂层之间低的粘结力是制约金属载体催化剂发展的瓶颈。该文报导了一个3步工序:碱蚀预处理→950℃氧化→浸渍涂层并焙烧。超声波振动和高温急冷后超声波振动分别用于测定活性涂层的脱落率。结果表明,整体型金属载体起始负载达到10%,在经超声波振动后,脱落率为1.4%。与此同时,还发现经碱蚀后的FeCrAl合金表面存在许多大小不一的“坑”。这些“坑”为后续的活性涂层起到钉扎作用。XRD分析可知,Fe-Cr固熔体在氧化层下面富集。SEM图象表明,煅烧后致密的氧化铝层在活性涂层和FeCrAl合金的界面形成,这极大地有益于增强活性γ-Al2O3涂层在FeCrAl合金箔材上的粘结力。
With the increasing problem of cold start emissions, metal-supported catalysts will be used in close-coupled catalysts soon after they are applied to the catalytic combustion of motorcycle exhaust and diesel exhaust. However, the low adhesion between the metal support and the active coating is the bottleneck that hinders the development of metal supported catalysts. This paper reports a three-step process: Alkaline etching pretreatment → 950 ° C oxidation → dip coating and calcination. Ultrasonic vibration and ultrasonic vibration after high temperature quenching were used to determine the exfoliation rate of the active coating. The results show that the initial load of monolithic metal carrier reaches 10%, and after ultrasonic vibration, the exfoliation rate is 1.4%. At the same time, it was also found that there are many sizes of “pit” on the surface of the as-eroded FeCrAl alloy. These “pits” pin the next active coating. XRD analysis shows that the Fe-Cr solid solution is enriched below the oxide layer. The SEM images show that the calcined alumina layer is formed at the interface between the active coating and the FeCrAl alloy, which greatly contributes to enhancing the adhesion of the active γ-Al2O3 coating on the FeCrAl alloy foil.