Corrosion Behavior of Ti Powder Enhanced Potassium Silicate Coating with Solid NaCl Deposit in Wet Oxygen at 500 °C

The potassium silicate coatings modified with various contents of Ti powders were prepared on the surfaces of Ti6Al-4V alloy. The corrosion tests of NaCl coated specimens were conducted in wet oxygen at 500 degrees C for 50 h. The corrosion depth of the bare Ti-6Al-4V alloy was deeper than 60 mu m while the mass gain reached to about 1.9 mg/ cm2 . All the coatings exhibited excellent protection against corrosion as corrosion products have been hardly detected. The main roles of the Ti powders in the coatings are believed to be prohibiting formation of micro-pores and oxygen permeation through the coatings.