Effects of sintering temperature and particle size on permeability of functionally gradient composite porous materials prepared by hanging slurry process

Porous materials have excellent functions in filtration and purification, and gradient composite porous materials enrich the product types of porous materials in the same field. In the preparation of metal-ceramic gradient composite porous materials, the matching relationship between the pore morphology and pore size of the metal porous matrix and the coated powder particles will seriously affect the structure and performance of the ceramic membrane. This work mentions the different size range (60, 100, 200 and 400 mesh) of 316 L stainless steel powder particles as the raw materials which are at different sintering temperatures of 1170, 1200 and 1230 degrees C, the fabrication of porous 316 L stainless steel substrate which was made by hanging slurry preparation of precursor, at the same time using Ar protection at different sintering temperatures (650, 700, 750 and 800 degrees C) to the preparation of metal-ceramic composite gradient according to different matrix apertures of porous materials. The pore structure, microstructure and morphology characteristics of different samples both of matrix and functionally gradient composite were analyzed and characterized. On the basis of test of permeability of functionally gradient composite porous materials, this kind of composite gradient porous material can be excellent at part of permeability which matrix was made by 400 mesh 316 L stainless steel powder particles at sintering temperature of 1230 degrees C and then dealed with the process of hanging slurry to became the precursor which ceramic membrane was prepared at sintering temperature of 650 degrees C. Maximum aperture of the porous substrate filtration precision under the combination of ceramic membrane layer can be increased by 96.3%. By observing the change of pore morphology of porous matrix, this paper aims to make a research of influence of sintering temperature and powder particles size on permeability of the functionally gradient composite porous materials, and also provide a reference for improving the filtration accuracy of existing porous materials.