Corrosion Behavior of SiO2-Al2O3 Glass Composite Coating on TC4 in Marine Environment

Compressor blades made of TC4 that are serviced in marine environments suffer from severe active corrosion under the synergetic effect of NaCl and H2O(g). A SiO2-Al2O3glass composite coating was applied on TC4 substrate for protection by first air spraying slurry and subsequent a suitable sintering process. The corrosion behavior of the SiO2-Al2O3glass composite coating and uncoated alloy in marine environment under the simultaneous effect of NaCl(s) and H2O(g) at 650 °C were investigated. The results indicated that the SiO2-Al2O3glass composite coating presented good corrosion behavior and provided protection for the alloy; the superior corrosion resistance is mainly attributed to the favorable effect of the SiO2-Al2O3glass composite coating on inhibiting self-sustainable oxychlorination. The detrimental effect of Ti on self-sustainable oxychlorination mechanism in marine environment are discussed.