|
4665 |
|
Tuesday, May 10, 2016, Yellow River Hall 2:40 PM Wind & Offshore |
|
Improved corrosion resistance and electrical insulation behavior of plasma sprayed alumina coatings treated by inorganic sealant |
|
Fang Shao* / Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Huayu Zhao / Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Kai Yang/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Chengguang Liu/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Shunyan Tao/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China |
|
In this study, alumina coatings have been deposited by atmospheric plasma spraying technique and sealed by inorganic sealant consisting of aluminum phosphate and small fraction of alumina nano particles. The sealing process was briefly described and the microstructure of the sealed coatings was examined. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and salt spray tests were used to evaluate anti-corrosive characteristics of the as-sprayed and sealed coatings, respectively. The corrosion potential of sealed coatings were much more positive than unsealed coatings. The corrosion current density of sealed coating was only about one sixth of that of unsealed coating. After sealing treatments, the impedance of the coating was also enhanced in both high and low frequencies range. After subjected to the salt fog test for 96 h, there were rusty corrosion products at the surface of the unsealed coatings while there was no visible corrosion on the sealed coatings. The results indicate that the sealing treatment is highly effective to inhibit corrosion. The electrical resistance was measured at room temperature under dry and humid conditions. Shows that the sealing treatment can enhance the anti-corrosion and insulating performance of alumina coatings by reducing the open porosity. |