Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8026832 | Surface and Coatings Technology | 2015 | 28 Pages |
Abstract
Zirconia coatings exhibiting widely technological applications were produced by plasma electrolytic oxidation (PEO) on ZrN-coated Si substrates in alkaline electrolytes. Firstly, zirconium nitride films were deposited on the substrates by an air-based reactive sputtering technique. After that, the specimens were electrochemically oxidized in 2Â M NaOH by applying voltages ranging from 42 to 55Â V for 30Â s. Spark discharge was observed over the specimens at the reaction voltages above 46Â V. X-ray diffraction patterns show resultant coatings comprised mainly tetragonal ZrO2 with slightly monoclinic ZrO2. The existence of fully spark discharge, highly crystalline phases, porous morphology, and high growth rate characterized the PEO coatings. The highly conductive ZrN seedling layer could facilitate significantly the growth of the coatings. Three types of reaction regimes were identified, including electrochemical oxidation, transition of electrochemical oxidation to PEO, and PEO. Biocorrosion tests revealed that the obtained PEO coatings could improve greatly the biocorrosion resistance. The formation mechanisms of the PEO-produced ZrO2 coatings are also discussed.
Related Topics
Physical Sciences and Engineering
Materials Science
Nanotechnology
Authors
Chuan-Han Hsiao, Huan-Ping Teng, Fu-Hsing Lu,