Process for producing of a pre-ceramic polymer coating with highly efficient protection against high-temperature corrosion of a commercial AISI 304 Stainless steel

摘要

Abstract : In recent years, low-cost and feasible route, has garnered interest for generating silica coatings which is mainly based on the use of silicon containing precursors like polysilazane. These pre-ceramic polymers are thermoset-materials containing a comparably short chain molecule that have been rearranged into a highly bonded rigid network during subsequent cross-linking process and lost their organic components to form an amorphous or nanostructured ceramic upon pyrolysis at higher temperature. An effective and low-cost method for applying polysilazane-based barrier coating on stainless steel is presented. A SIN (PHPS) precursor has been used for applications of polymeric and ceramic-like coating material. With precursor solution in dibutyl ether, AISI 304 stainless steel substrates were coated by means of a simple dip coating technique. After pyrolysis stage at 800°C, the efficiency of the PHPS-based coating has been proved, and oxidation tests were done at 900°C in air. By measuring the weight gain, and by using of analytical techniques as in situ X-Ray Diffraction and Scanning Electron Microscopy, an amorphous silica layer formed from the initial PHPS-based coating acts as a protective glass which provides complete separation of the AISI 304 steel surface from the oxidizing environment. This protective silica layer appears to be a very good diffusion barrier by preventing iron-containing oxide formation.