Role of Sodium Silicate for Coating Forming on Magnesium Alloys with Micro Arc Oxidation

doi:10.13373/j.cnki.cjrm.XY18090038

	Role of Sodium Silicate for Coating Forming on Magnesium Alloys with Micro Arc Oxidation
	Sun, Le; Ma, Ying; Dong, Hairong; An, Lingyun; Wang, Sheng
	2020-04-01
发表期刊	Xiyou Jinshu/Chinese Journal of Rare Metals
ISSN	02587076
卷号	44 期号:4 页码:378-386
摘要	AZ91D magnesium alloys were processed by micro arc oxidation (MAO) in electrolytes without and with sodium silicate, respectively. The role of sodium silicate during MAO treatment was investigated and its effect on MAO coatings was analyzed. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were employed to characterize the microstructure and phase composition of MAO coatings, respectively. And the corrosion resistance of MAO coatings was evaluated by electrochemical workstation. The results showed that a complete, uniform coating was obtained during MAO treatment once sodium silicate was added into the electrolyte, and in turn, the coating's compactness was improved and a new phase Mg2SiO4 with excellent properties was generated in the coatings. With addition of sodium silicate into the electrolyte, the solution conductivity increased and the ignition voltage on specimen surfaces decreased during MAO process, which facilitated a breakdown easily developing on specimen surfaces. Further on this foundation, the competing state in terms of the potential levels in different areas would be enhanced on the anode surface under the coactions between the silicate ions and other anions in the electrolyte, which, in turn, accelerated the sparks' moving phenomena around the coatings' surfaces due to the igniting and extinguishing of the sparks appearing alternately on specimen surfaces. Consequently, the macro-scale pits and the micro-cracks caused by the local thermal accumulation had eliminated on the coatings' surfaces. As a result, the corrosion resistance of MAO coatings formed in the electrolyte with sodium silicate was improved obviously by demonstration of the decreasing of the corrosion current density of the coatings with one order of magnitude and increasing of their linear polarization resistance with sixteen times. © Editorial Office of Chinese Journal of Rare Metals. All right reserved.
关键词	Corrosion resistance Electrolytes Magnesium alloys Magnesium compounds Scanning electron microscopy Silicates Sodium compounds Sodium silicate process AZ91D magnesium alloys Corrosion current densities Ignition voltage Linear polarization resistance Microarc oxidation Solution conductivity Specimen surfaces Thermal accumulation
DOI	10.13373/j.cnki.cjrm.XY18090038
收录类别	EI
语种	中文
出版者	Editorial Office of Chinese Journal of Rare Metals
EI入藏号	20202108708117
EI主题词	Corrosion resistant coatings
EI分类号	534.2 Foundry Practice - 539.1 Metals Corrosion - 542.2 Magnesium and Alloys - 702 Electric Batteries and Fuel Cells - 803 Chemical Agents and Basic Industrial Chemicals - 804 Chemical Products Generally
来源库	Compendex
分类代码	534.2 Foundry Practice - 539.1 Metals Corrosion - 542.2 Magnesium and Alloys - 702 Electric Batteries and Fuel Cells - 803 Chemical Agents and Basic Industrial Chemicals - 804 Chemical Products Generally
引用统计	无
文献类型	期刊论文
条目标识符	https://ir.lut.edu.cn/handle/2XXMBERH/115197
专题	材料科学与工程学院
作者单位	State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou; 730050, China
第一作者单位	兰州理工大学
第一作者的第一单位	兰州理工大学
推荐引用方式 GB/T 7714	Sun, Le,Ma, Ying,Dong, Hairong,et al. Role of Sodium Silicate for Coating Forming on Magnesium Alloys with Micro Arc Oxidation[J]. Xiyou Jinshu/Chinese Journal of Rare Metals,2020,44(4):378-386.
APA	Sun, Le,Ma, Ying,Dong, Hairong,An, Lingyun,&Wang, Sheng.(2020).Role of Sodium Silicate for Coating Forming on Magnesium Alloys with Micro Arc Oxidation.Xiyou Jinshu/Chinese Journal of Rare Metals,44(4),378-386.
MLA	Sun, Le,et al."Role of Sodium Silicate for Coating Forming on Magnesium Alloys with Micro Arc Oxidation".Xiyou Jinshu/Chinese Journal of Rare Metals 44.4(2020):378-386.