Fabrication of TiO₂ ceramic membrane on stainless steel substrates

Metallic membranes were gradually used in filtration and separation because of their high strength compared with organic and inorganic membranes; however, less reports about their preparation technology were found. In this work, the fabrication technology was studied. Sol-Gel method was used to fabricate TiO₂ ceramic membranes on 304 stainless steel substrates (SUS). Some factors, such as concentration, pH value of the sol, binders and sintering temperature were explored. Two type binders (polyvinyl alcohol (PVA) and methyl cellulose (MC)) were used to prepare casting solutions. One casting solution marked as 1# was prepared by adding 1% PVA into 0.07M sol and adjusting its pH value to 2.0, the other marked as 2# was prepared by adding 0.3% MC into 0.07M sol, 304 SUS pieces were then dip-coated into the solutions. The dried pieces dip-coated into 1# solution were sintered at 600℃ and those dip-coated into 2# were sintered at 700℃. A flake-like morphology and a grain-like morphology were obtained, respectively.　Besides, the XRD results showed that the anatase and rutile phase existed in the membrane with flake-like morphology and the pure rutile phase was obtained in the membrane with grain-like morphology. Both of the casting solutions were able to form continuous TiO₂ membranes on 304 SUS. The obtained two types of morphologies existed pores which can be used to filtrate. The results show that sol-gel method is a promising method to obtain membranes with pores on metal substrates.