| WANG Yi.Electrodepositing Cr-WO3 Nano-composite Coating and Its Performance Evaluation[J],46(2):92-97 |
| Electrodepositing Cr-WO3 Nano-composite Coating and Its Performance Evaluation |
| Received:September 12, 2016 Revised:February 20, 2017 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2017.02.014 |
| KeyWord:electrodeposition composite coating WO3 corrosion resistance chroming electrochemical impedance hardness |
| Author | Institution |
| WANG Yi |
Technique Center, Laiwu Branch Company of Shandong Iron&Steel Group Co., Ltd, Laiwu , China |
|
| Hits: |
| Download times: |
| Abstract: |
| The work aims to improve corrosion resistance and thermal stability of chromium coating on low carbon steel. Nano WO3 particles were dispersed in chromium plating bath, and the Cr-WO3 nano composite coating was electrodeposited by direct-current electrodeposition from citric acid-sulfate bath. Then surface microtopography of the coating was observed by metallographic microscope and X-ray diffractometer (XRD), and phase structure of the coating was tested. Hardness and corrosion resistance of the Cr-WO3 nano composite coating were evaluated by virtue of Vickers hardness test, polarization curve and electrochemical impedance test. Lamellar grain structure was present on the surfaces of Cr coating and Cr-WO3 nano composite coating, the grain size of Cr-WO3 nano composite coating was smaller than that of Cr coating. Electrochemical testing was performed in 5wt.% NaCl solution. Compared with the Cr coating, corrosion current density (Jcorr) of Cr-WO3 nano-composite coating decreased to 0.38 μA/cm2, electrochemical impendence increased, electrochemical activity was lower and corrosion resistance was better. The hardness of Cr-WO3 nano-composite coating was close to that of Cr coating. Addition of Cr-WO3 did not contribute to higher hardness, but it could prevent presence and expansion of cracks on the coating during annealing, and reduce changes of coating surface states. Cr-WO3 particles could be mixed in the coating effectively to reduce grain size of the coating. The lower electrochemical activity of the Cr-WO3 nano-composite coating is, the better the corrosion resistance will be. WO3 nano has minor influence on the hardness of unannealed coating. However, it can reduce the value of amplitude of annealed coating and improve its thermal stability. |
| Close |
|
|
|