Preparation of silicon-modified gamma alumina coating through cathodic plasma electrolytic deposition

Abstract

Abstract The commonly used γ-alumina catalyst carrier for industrial production usually degrades as a result of the reduction of the specific surface area because of the transition to α-alumina at a high temperature. To enhance the phase stability, γ-alumina coatings were modified using silicon on a high-temperature nickel-based alloy through cathodic plasma electrolytic deposition (CPED). The effects of the silicon content and heat treatment on the morphology and phase stability of the coating were investigated. Furthermore, the deposition process of CPED was studied. The experimental results indicated that silicon was successfully introduced into γ-alumina coatings in two forms, namely the solid solution and oxidation states (silica). Deposition of doped silicon through cathodic plasma electrolysis inhibited the conversion from γ-alumina to α-alumina. The doped silicon content influenced the structure of the coated pores.