A Study On The Alumina Washcoat Supported By Fe-Cr-Al Alloy

The metallic support ,with many fine properties compared with ceramic support.is a sort of carrier with practical perspective for automotive exhaust control.However,the washcoat of alumina supported by metal is apt to come off and age at elevated temperature.as limits the use of metallic support.So the study to resolve these two questions has a practical significance.In this paper;the transitive layer between support of Fe-Cr-Al and washcoat of alumina,and the thermal stability of the washcoat have studied in the laboratory.The technologies such as erosion of CuSO4,SEM,BET were used to examine the resistance of phosphate toerosion, the morphology and component and specific area of washcoat.The results revealed that the resistance of phosphate to erosion at elevated temperature is poor.Phosphate layer is not qualified for transitive layer.The oxidation layer,which develop on the surface of support at elevated temperature.is qualified for transitive layer.The extent of density of oxidation layer is a function of temperature and time.The introduction of promoters such as La2O3, CeO2, CaO, BaO and SiO2 has increased the thermal stability of the washcoat at elevated temperature and prevented the decrease of specific area of transitive alumina.However the extent of stability is different when the species and amount of promoters is different. In gross, introduction of BaO and SiO2 can sinally stabilize the specific area of transitive alumina.