Preparation And Performance Study Of Al₂O₃/Fe-Cr-Ni Composite Honeycomb Carrier Material

In recent years,with the rapid development of economy,as one of the pillar industries of our country,automobile industry has also got considerable development.With car ownership increasing,environmental pollution caused by automobile exhaust is becoming more and more serious.At present,the main way to control automobile exhaust emission is to purify automobile exhaust through automobile exhaust purifier.The common carriers of automobile exhaust purifier mainly include ceramic honeycombs and metal honeycombs.Ceramic honeycombs are low cost,but its thermal conductivity is poor and its mechanical strength is low.Metal honeycombs have good mechanical properties,but its binding ability with catalytic coating is weak,high temperature oxidation resistance is not good enough,and its preparation process is very complex and costly.Therefore,how to prepare carriers of exhaust purifier with excellent performance and relatively low cost has become an urgent problem to be solved.Stainless steel powder,aluminium powder and iron oxide powder were used as raw material.The powder plasticizing extrusion technology was used to prepare metal honeycomb material.Al₂O₃/Fe-Cr-Ni composite honeycomb materials with good performance was fabricated by in situ reaction of Fe₂O₃ powder and Al powder in the sintering process.The contents and results are as follows:1.316L stainless steel powder,aluminium powder and iron oxide powder were used as raw material.Al₂O₃/Fe-Cr-Ni composite materials was successfully fabricated by powder plasticizing extrusion,drying and sintering process.2.In the Al2O3/Fe-Cr-Ni composite honeycomb extruding process,the optimum extrusion rate is 10cm/min,the optimum pressure is 5⁸Mpa,the best sizing circle is 32.4mm,the best ratio of solid powder is 73%⁷7%.3.The effects of sintering temperature and Al₂O₃ contents on volume shrinkage and apparent density of Al₂O₃/Fe-Cr-Ni composite honeycombs was discussed.The study found that the volume shrinkage and apparent density of Al₂O₃/Fe-Cr-Ni composite honeycombs increase with the increase of sintering temperature.With the increase of Al₂O₃ contents,Al₂O₃/Fe-Cr-Ni composite honeycombs volume shrinkage and apparent density decrease.The optimum sintering temperature is 1200?.4.The influence of sintering temperature and Al2O3 contents on microstructure of Al2O3/Fe-Cr-Ni composite honeycomb sample was studied.The matrix structure of Al₂O₃/Fe-Cr-Ni composite honeycomb is?-Fe?NiCr?.Al₂O₃ is distributed in the metal matrix,partly agglomerated in pores of matrix grains,partly in matrix grains.With the increase of sintering temperature,metal particle bonding together,and the connectivity of the matrix is enhanced.5.The influence of sintering temperature and Al₂O₃ contents on stress-strain curve of Al2O3/Fe-Cr-Ni composite honeycomb samples was discussed.When the content of Al₂O₃ is low,the content of Al₂O₃ has little effect on the compressive strength of samples,but with the increase of the content of Al₂O₃,the compressive strength of the samples decrease rapidly.When the content of Al₂O₃ is 1.5%and the sintering temperature is 1200 C,the compressive strength of the sample reaches 31.49MPa.6.the effects of Al₂O₃ content on the oxidation resistance and surface adhesion of Al₂O₃/Fe-Cr-Ni composite honeycomb carrier materials was discussed.Experimental result shows that,at high temperature,the oxidation resistance of the samples increases with the increase of Al₂O₃ content,and surface adhesion of the samples increases with the increase of Al₂O₃ content.