Not only the coating material corrosion resistance, but also the coating-substrate interface crack resistance and coating permeation to liquor and its vapor are found to be critical factors affecting the coating performance in Kraft pulping digesters. The behavior of electric-arc and HVOF sprayed coatings is discussed.
Keywords: Krafl pulping, continuous and batch digester, coating, alloy 625, gas permeability, sulfidation, crack resistance, electric arc spraying, high-velocity oxygen-fuel spraying