ZENG Ji-yong,GUO Xing-wu,GUO Jia-cheng,NIE Le-wen,GONG Lei-chao,PENG Li-ming,DING Wen-jiang.Preparation of New Phytic Acid Chemical Conversion Coating with Excellent Corrosion Resistance on Magnesium Alloys[J],48(10):230-237
Preparation of New Phytic Acid Chemical Conversion Coating with Excellent Corrosion Resistance on Magnesium Alloys
Received:May 07, 2019  Revised:October 20, 2019
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DOI:10.16490/j.cnki.issn.1001-3660.2019.10.028
KeyWord:magnesium alloy  phytic acid  chemical conversion coating  orthogonal experiment  corrosion resistance
                    
AuthorInstitution
ZENG Ji-yong 1.National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai , China
GUO Xing-wu 1.National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai , China; 2.Shanghai Innovation Institute for Materials, Shanghai , China
GUO Jia-cheng 1.National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai , China
NIE Le-wen 1.National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai , China
GONG Lei-chao 1.National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai , China
PENG Li-ming 1.National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai , China; 2.Shanghai Innovation Institute for Materials, Shanghai , China
DING Wen-jiang 1.National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai , China; 2.Shanghai Innovation Institute for Materials, Shanghai , China
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Abstract:
      The work aims to improve the corrosion resistance of magnesium alloy. A new type of phytic acid chemical conversion coating with high corrosion resistance was obtained based on single phytic acid chemical conversion coatings by introducing metal ions into the reaction solution through the strong interaction of phytic acid. The process formula, microstructure, elemental composition and corrosion resistance of the new coating were analyzed by orthogonal experiment, SEM, EDS and electrochemical method. The optimal process parameters of the new phytic acid conversion coating obtained through orthogonal experiment included 25 g/L of Mn(H2PO4)2, 10 g/L of phytic acid, reaction temperature of 95 ℃ and reaction time of 10 min. The phytic acid coating prepared by the optimal process had a uniform surface and contained fewer cracks, compared with the coating without Mn ions. The EDS results showed that the main elements of the coating were Mg, P, O, Mn, and C. The composition was a complex of manganese and magnesium phytate. The results of the potentiodynamic polarization curves showed that the new coating could greatly reduce the self-corrosion current density (Jcorr=0.337 ) of the magnesium alloy, and the protection efficiency for the magnesium alloy was 96.37%. Adding Mn into the phytic acid conversion coating cannot only reduce the width of the phytic acid coating cracks, but also greatly improve the corrosion resistance of magnesium alloy.
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