Production and electrochemical properties of the sol–gel α-Al2O3 coated stainless steel foams

Abstract

17–4 PH martensitic stainless steel foams are frequently used in surgery and dental tools. Porous morphology may increase the usage fields of these foams for biomedical aims. In this work, highly porous 17–4 PH martensitic stainless steel foams were produced with the space holder technique and coated with α-Al2O3 to improve chemical stability and surface properties. Mixing stainless steel, boron powders, and urea with polyvinyl alcohol, pressing the mixture at 180 MPa, removing the urea by dissolving it in water at room temperature, and then removing the binder in the raw pellets through sintering were sequentially performed to prepare the foams. Afterwards, the foams were dip-coated in sol–gel derived AlOOH gel for 7–14-21 days and, finally, heat-treated at 1260 °C to transform AlOOH into α-Al2O3. The physical, microstructural, and electrochemical properties of the foams were characterized. The metal ion release from the samples decreased thanks to the α-Al2O3 layer.