Al 2Preparation, Microstructure And Properties Of O 3 /430L Honeycomb Carrier Materials

With the continuous improvement of the national economy in recent years,the automobile industry as a pillar industry in China has been rapidly developed from 2011 to 2016,the national motor vehicle ownership from the original 225 million rapidly increase to 290 million.China ranked first in the world.With the increase in the use of vehicle,at the same time the air pollution is also increasingly serious.The amount of pollution caused by vehicle emissions to the human body and the natural environment is also rising in a straight line,therefore,the control and improvement of exhaust pollution and the protection of natural environment are highly regarded by all countries in the world.This paper is on the study of plasticizing powder extrusion technology on the basis of preparation of metal honeycomb material,combined with the carrier material performance requirement and material selection principle,to use a cheaper 430L alloy powders and Al₂O₃ powder as raw materials,Al₂O₃/430L honeycomb materials are fabricated by plasticizing powder extrusion technology.Compared with 316L stainless steel powder,the price of 430L stainless steel powder is reduced by half.In this paper,we mainly study the effects of different content of Al₂O₃ on the microstructure,oxidation resistance,coating performance and mechanical properties of Al₂O₃/430L honeycomb materials.The contents and results are as follows:1.430L alloy powder and AI2O3 powder are as raw materials.The Al₂O₃/430L honeycomb materials were successfully prepared by powder plasticizing extrusion,drying and sintering process.2.In the Al₂O₃/430L honeycomb extruding process,the optimum extrusion rate is 15cm/min,the optimum pressure is 5?8MPa,the best sizing circle is 32.4mm,the best ratio of solid powder is 78%and 79%.3.The effects of sintering time,temperature and Al₂O₃ content on Al₂O₃/430L honeycomb carrier were analyzed.Under vacuum sintering conditions,the volume shrinkage and apparent density of metal honeycomb samples increase with increasing sintering temperature or sintering time.When the content of Al₂O₃ ceramic powder is Owt%-2.5wt%,the shrinkage and apparent density of metal honeycomb samples increase gradually.When the content of Al₂O₃ ceramic powder is more than 2.5wt.%,the shrinkage and apparent density of metal honeycomb samples decrease gradually.The effects of sintering temperature and sintering time on the microstructure of Al₂O₃/430L honeycomb were investigated.The optimum sintering temperature?1100??and sintering time?120min?were determined..4.The influence of sintering temperature and sintering time on microstructure of Al₂O₃/430L honeycomb sample was studied.Under vacuum sintering conditions,The matrix of the sintered Al₂O₃/43OL honeycomb sample is a-Fe?Cr?solid solution,and the Al₂O₃ ceramic phase is mainly distributed in the pore between the matrix and the matrix grain.With the increase of sintering temperature and the increase of time,the bonding surface between the metal powder particles increases,the interstitial space between the matrix is reduced,and the connectedness of the matrix is enhanced.5.The effects of Al₂O₃ on the antioxidant,surface adhesion and mechanical properties of Al₂O₃/430L honeycomb carrier were studied.The results show:in the high temperature oxidation environment,The surface bonding strength of honeycomb carriers with catalytic coating increases with the amount of Al₂O₃ increasing.Compressive strength of the part increases at first and then decreases with the increase of the content of Al₂O₃,and the peak value reaches at 2.5wt.%Al₂O₃and maximum compressive strength 27 MPa.The Al₂O₃/43OL honeycomb with 2.5wt.%Al₂O₃ have best mechanical properties and high surface coating adhesion.