The addition of 2,5-pyridinedicarboxylic acid(2,5-PDCA)to the Mg-Al LDH coating,which was prepared by one-step hydrothermal synthesis,had extremely enhanced the corrosion protection of AZ31 Mg alloy,although the 2,5-P...The addition of 2,5-pyridinedicarboxylic acid(2,5-PDCA)to the Mg-Al LDH coating,which was prepared by one-step hydrothermal synthesis,had extremely enhanced the corrosion protection of AZ31 Mg alloy,although the 2,5-PDCA could not be intercalated into the interlayer spacing.The corrosion current density of 0.05 mol L^(−1)2,5-PDCA LDH containing LDH coating is 3.18 nA cm^(−2),reduced by two orders of magnitude compared to the LDH coating without inhibitor,and the corrosion inhibition efficiency of the coating is 98.05%.The coating formed on the surface of AZ31 was peeled off from the substrate by using a mechanical method and SEM observation of the cross-section showed that the coating consisted of three different layers.The innermost layer is a thick layer that consists of Mg(OH)_(2)and the intermediate layer is LDH,which is vertical to the substrate and the outmost layer is a thin but very dense deposit layer of LDH agglomerates with complexes of 2,5-PDCA and Mg.This kind of sediment/LDH/Mg(OH)_(2)three-layer composite structure was accountable for the increase in the corrosion resistance of AZ31 Mg alloy.展开更多
Methods for evaluating the resistance to cathodic disbondment （RCD） of anti-corrosion coatings on buried pipelines were reviewed. It is obvious that these traditional cathodic disbondment tests （CDT） have some dis...Methods for evaluating the resistance to cathodic disbondment （RCD） of anti-corrosion coatings on buried pipelines were reviewed. It is obvious that these traditional cathodic disbondment tests （CDT） have some disadvantages and the evaluated results are only simple figures and always rely on the subjective experience of the operator. A new electrochemical method for evaluating the RCD of coatings, that is, the potentiostatic evaluation method （PEM）, was developed and studied. During potentiostatic anodic polarization testing, the changes of stable polarization current of specimens before and after cathodic disbonding （CD） were measured, and the degree of cathodic disbondment of the coating was quantitatively evaluated, among which the equivalent cathodic disbonded distance AD was suggested as a parameter for evaluating the RCD. A series of testing parameters of the PEM were determined in these experiments.展开更多
目前商用聚烯烃隔膜存在电解液亲和性和热稳定性差等问题,导致所组装电池的充放电性能和安全性有所欠缺。为改善电解液的亲和性及热稳定性,采用聚乙烯醇为黏结剂将纳米碳酸钙涂覆至聚丙烯隔膜表面,通过扫描电子显微镜、电化学测试、热...目前商用聚烯烃隔膜存在电解液亲和性和热稳定性差等问题,导致所组装电池的充放电性能和安全性有所欠缺。为改善电解液的亲和性及热稳定性,采用聚乙烯醇为黏结剂将纳米碳酸钙涂覆至聚丙烯隔膜表面,通过扫描电子显微镜、电化学测试、热稳定性分析等方法对改性后的隔膜进行了研究。结果表明,纳米碳酸钙质量分数为1.5%的改性隔膜孔隙率可达到46.47%±0.42%,电解液吸液率提升到168.03%±3.46%,改性后隔膜的电解液亲和性得到了改善。170℃时热收缩率为18.59%±4.12%,拉伸强度提升至169 MPa左右,隔膜的热稳定性与力学性能得到提升。改性后隔膜的离子电导率从0.50 m S/cm提升到了0.78 mS/cm,500次充放电循环后磷酸铁锂正极的放电比容量保持率为84.10%,并且在充放电循环过程中更加稳定。展开更多
文摘The addition of 2,5-pyridinedicarboxylic acid(2,5-PDCA)to the Mg-Al LDH coating,which was prepared by one-step hydrothermal synthesis,had extremely enhanced the corrosion protection of AZ31 Mg alloy,although the 2,5-PDCA could not be intercalated into the interlayer spacing.The corrosion current density of 0.05 mol L^(−1)2,5-PDCA LDH containing LDH coating is 3.18 nA cm^(−2),reduced by two orders of magnitude compared to the LDH coating without inhibitor,and the corrosion inhibition efficiency of the coating is 98.05%.The coating formed on the surface of AZ31 was peeled off from the substrate by using a mechanical method and SEM observation of the cross-section showed that the coating consisted of three different layers.The innermost layer is a thick layer that consists of Mg(OH)_(2)and the intermediate layer is LDH,which is vertical to the substrate and the outmost layer is a thin but very dense deposit layer of LDH agglomerates with complexes of 2,5-PDCA and Mg.This kind of sediment/LDH/Mg(OH)_(2)three-layer composite structure was accountable for the increase in the corrosion resistance of AZ31 Mg alloy.
基金This work is financially supported by the National Natural Science Foundation of China (No.2992021).
文摘Methods for evaluating the resistance to cathodic disbondment （RCD） of anti-corrosion coatings on buried pipelines were reviewed. It is obvious that these traditional cathodic disbondment tests （CDT） have some disadvantages and the evaluated results are only simple figures and always rely on the subjective experience of the operator. A new electrochemical method for evaluating the RCD of coatings, that is, the potentiostatic evaluation method （PEM）, was developed and studied. During potentiostatic anodic polarization testing, the changes of stable polarization current of specimens before and after cathodic disbonding （CD） were measured, and the degree of cathodic disbondment of the coating was quantitatively evaluated, among which the equivalent cathodic disbonded distance AD was suggested as a parameter for evaluating the RCD. A series of testing parameters of the PEM were determined in these experiments.
文摘目前商用聚烯烃隔膜存在电解液亲和性和热稳定性差等问题,导致所组装电池的充放电性能和安全性有所欠缺。为改善电解液的亲和性及热稳定性,采用聚乙烯醇为黏结剂将纳米碳酸钙涂覆至聚丙烯隔膜表面,通过扫描电子显微镜、电化学测试、热稳定性分析等方法对改性后的隔膜进行了研究。结果表明,纳米碳酸钙质量分数为1.5%的改性隔膜孔隙率可达到46.47%±0.42%,电解液吸液率提升到168.03%±3.46%,改性后隔膜的电解液亲和性得到了改善。170℃时热收缩率为18.59%±4.12%,拉伸强度提升至169 MPa左右,隔膜的热稳定性与力学性能得到提升。改性后隔膜的离子电导率从0.50 m S/cm提升到了0.78 mS/cm,500次充放电循环后磷酸铁锂正极的放电比容量保持率为84.10%,并且在充放电循环过程中更加稳定。
