Study On Preparation Process Of Porous Stainless Steel

Porous stainless steel materials have got wide and extensive applications in the fields of medical as drug-carrying implantable devices,intelligent materials of stainless steel,solid oxide fuel cell,super capacitor,high-temperature filter,heat exchanger and so on because of the advantages of high specific surface area,high pore rate,good biocompatibility,good electromagnetic shielding,excellent physico-chemical and mechanical performance such as high electrical and thermal conductivity coefficient,high temperature,pressure and corrosion resistance,as well as weldability and low prices of raw materials.In many traditional and new areas of material science,more and more attention and research have been focused on porous stainless steel materials,which have important and irreplaceable roles in material application.In this study,different contents of Mn alloys,316L-30 Mn,316L-40 Mn,316L-50 Mn,were prepared successfully.The three-dimensional connected voids with0.5 ~ 2 ?m were successfully manufactured by physical vacuum dealloying using the high vapor pressure of manganese,Kirkendall effect,and the difference in the diffusion rate of Fe and Mn elements.The ligament size ranges from 0.5 ?m to 7 ?m with the porosity 1 ~ 60 %.The feasibility of the preparation of porous stainless steel by physical vacuum dealloying was verified,which provides a new process for manufacturing micro porous stainless steel.When the porous stainless steel was made by physical vacuum dealloying,the pore size,porosity and pore morphology of the porous stainless steel were mainly affected by temperature.The pore structure of the porous stainless steel was changed by affecting the saturated vapor pressure and diffusion coefficient of the manganese element.The optimum vacuum heat treatment temperature of 316L-xMn stainless steel was 850 ~ 900?.The vacuum heat treatment time mainly affected the thickness of the porous layer,and the thickness of the 316L-x Mn stainless steel was 0 ~ 100 ?m with the increasing vacuum heat treatment time.Moreover,the content of manganese had certain influences on porosity of porous stainless steel.In addition,the sintering process of 316L-50 Mn alloy was studied by powder sintering method.The optimum sintering process was 1100?,4 h.Porous stainless steel with two void sizes was prepared by the combination of powder sintering and physical vacuum dealloying,by taking advantage of binding and space holding dual ability of manganese element.The manufacturing process of the combination of powder sintering and chemical dealloying was tried.The porous stainless steel with strip structure on the surface was successfully fabricated.