Effect of enamel coating on long-term oxidation of Ti65 alloy

Long-term isothermal and cyclic oxidation behaviour of Ti65 alloy and the effect of enamel coating at 650°C were studied. After 1000 h oxidation, adhesive, but less protective TiO2 scale formed on Ti65 alloy and oxygen dissolution in the substrate was high. Enamel coating remarkably reduced the isothermal and cyclic oxidation rate. Even after 1000 h isothermal or cyclic oxidation, enamel coating was very adherent to substrate and neither crack nor spallation appeared in the coating. However, interdiffusion between the enamel coating and the substrate occurred, which may be inferior to the mechanical properties of the alloy. Further study should be carried out in modification of firing process of enamel coating or application of aluminum coating between the enamel coating and the base alloy.