模拟海洋大气环境下铝合金表面锌黄环氧底漆/丙烯酸聚氨酯面漆涂层体系失效过程研究
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摘要
目的研究5A06型铝基材所使用的锌黄环氧底漆/丙烯酸聚氨酯面漆涂层体系的失效过程。方法设计"紫外/冷凝3 d+中性盐雾3 d+低温暴露1 d"为一个周期的实验室循环加速试验,采用交流阻抗谱法,结合光泽度、色差值、红外光谱等数据,研究涂层体系性能。结果循环加速试验进行到16周,该过程中面漆的失光率、色差值上升,达到轻微失光等级和轻微变色等级。面漆的表面形貌及涂层的低频阻抗发生明显变化,第12周时在光学显微镜下明显可见微小鼓泡,涂层0.1 Hz阻抗保持在109W·cm~2以上,但此后鼓泡数量增加,部分鼓泡破损,颜填料流出;第14周时,0.1 Hz阻抗下降到108W·cm~2,此后鼓泡数量进一步增加,部分鼓泡处面漆脱落;第16周时,0.1 Hz阻抗下降到约为107W·cm~2。结论丙烯酸聚氨酯面漆树脂基体特征官能团、聚合物链发生断裂,面漆的完整性遭到破坏,这可能与紫外线照射相关。这将加速涂层中腐蚀性介质(如水、氧和侵蚀性氯离子)渗透,促进涂层的失效。
The work aims to study the failure process of a composite coating system composed of zinc yellow epoxy primer and acrylic polyurethane topcoat used in 5A06 aluminum substrate. The laboratory cyclic accelerated test with a cycle of "UV/condensation for 3 days, neutral salt spray for 3 days and low temperature exposure for 1 day" was designed. The performance of the composite coating was studied by adopting AC impedance spectroscopy and measuring gloss, color difference and IR. At 16 cycles of the cyclic accelerated test, the gloss loss and color difference of the topcoat increased to the level of slight loss of gloss and slight discoloration. The surface morphology of the topcoat and the impedance module changed obviously. At 12 cycles, small blister was observed obviously in the optical microscope, but the impedance module at 0.01 Hz of the coating remained above 109 W·cm~2. From 12 th cycles, the number of blisters increased and some of broken blisters caused the out flowing of pigment. At 14 cycles, the impedance module at 0.01 Hz lowered to 108 W·cm~2. The blisters continuously increased and part of them peeled off. At 16 cycles, the impedance at 0.01 Hz lowered to 107 W·cm~2. The breakage of characteristic functional groups and polymer chains of the resin matrix of acrylic polyurethane topcoat, and incompleteness of the coating may be caused by UV irradiation and accelerate the permeation of the corrosive medium such as water, oxygen and corrosive chloride, thus resulting in coating failure.
The work aims to study the failure process of a composite coating system composed of zinc yellow epoxy primer and acrylic polyurethane topcoat used in 5A06 aluminum substrate. The laboratory cyclic accelerated test with a cycle of "UV/condensation for 3 days, neutral salt spray for 3 days and low temperature exposure for 1 day" was designed. The performance of the composite coating was studied by adopting AC impedance spectroscopy and measuring gloss, color difference and IR. At 16 cycles of the cyclic accelerated test, the gloss loss and color difference of the topcoat increased to the level of slight loss of gloss and slight discoloration. The surface morphology of the topcoat and the impedance module changed obviously. At 12 cycles, small blister was observed obviously in the optical microscope, but the impedance module at 0.01 Hz of the coating remained above 109 W·cm~2. From 12 th cycles, the number of blisters increased and some of broken blisters caused the out flowing of pigment. At 14 cycles, the impedance module at 0.01 Hz lowered to 108 W·cm~2. The blisters continuously increased and part of them peeled off. At 16 cycles, the impedance at 0.01 Hz lowered to 107 W·cm~2. The breakage of characteristic functional groups and polymer chains of the resin matrix of acrylic polyurethane topcoat, and incompleteness of the coating may be caused by UV irradiation and accelerate the permeation of the corrosive medium such as water, oxygen and corrosive chloride, thus resulting in coating failure.
引文
[1]HU Jian-wen,GAO Jin,LI Xiao-gang,et al.An Investigation of UV Photo-degradation on Acrylic Polyurethane Varnish Coatings[J].Journal of Chinese Society for Corrosion and Protection,2009,29(5):371-375.
[2]罗振华,蔡键平,张晓云,等.耐候性有机涂层加速老化试验研究进展[J].合成材料老化与应用,2003,32(3):31-35.LUO Zhen-hua,CAI Jian-ping,ZHANG Xiao-yun,et al.Progress in Study of Accelerated Test for Anti-weathering Organic Coatings[J].Synthetic Materials Aging and Application,2003,32(3):31-35.
[3]林宏升,罗敏,陈宇豪,等.高耐候丙烯酸聚氨酯涂层的防腐蚀性能[J].材料保护,2015,48(9):47-49.LIN Hong-sheng,LUO Min,CHEN Yu-hao,et al.Anti-corrosion Performance of Highly Weather Resistant Acrylic Polyurethane Coating[J].Materials Protection,2015,48(9):47-49.
[4]杨丽霞,李晓刚,张三平.丙烯酸聚氨酯涂层在我国典型大气环境下的老化历程[J].环境技术,2006,24(6):19-22.YANG Li-xia,LI Xiao-gang,ZHANG San-ping.Aging Course of Acrylic Polyurethane Coating Exposed in Representative Atmosphere of Our Country[J].Environmental Technology,2006,24(6):19-22.
[5]卢琳,胡建文,李晓刚,等.光老化对丙烯酸聚氨酯/钢板界面附着力的影响[J].复合材料学报,2011,28(2):94-99.LU Lin,HU Jian-wen,LI Xiao-gang,et al.Effect of Photo Degradation on the Adhesion at Acrylic Polyurethane Varnish/Steel Interface[J].Acta Materiae Compositae Sinica,2011,28(2):94-99.
[6]MERLATTI C,PERRIN F X,ARAGON E,et al.Natural and Artificial Weathering Characteristics of Stabilized Acrylic-urethane Paints[J].Polymer Degradation&Stability,2008,93(5):896-903.
[7]耿舒,高瑾,李晓刚,等.丙烯酸聚氨酯涂层的紫外老化行为[J].北京科技大学学报,2009,31(6):752-757.GENG Shu,GAO Jin,LI Xiao-gang,et al.Aging Behaviors of Acrylic Polyurethane Coatings During UV Irradiation[J].Journal of University of Science and Technology Beijing,2009,31(6):752-757.
[8]李倩倩,李晖,郑会保,等.丙烯酸聚氨酯涂层万宁近海地区自然老化历程与机理[J].涂料工业,2016,46(3):12-18.LI Qian-qian,LI Hui,ZHENG Hui-bao,et al.Natural Aging Process and Mechanism of Acrylic Polyurethane Coating in Wanning Coastal Area[J].Paint&Coatings Industry,2016,46(3):12-18.
[9]王玲,高瑾,李晓刚,等.光辐射对丙烯酸聚氨酯涂层防腐保护性能的影响[J].北京科技大学学报,2008,30(2):152-155.WANG Ling,GAO Jin,LI Xiao-gang,et al.Effect of Photo-radiation on Anti-corrosion and Protection Performance of Acrylic Polyurethane Coating[J].Journal of University of Science and Technology Beijing,2008,30(2):152-155.
[10]IRIGOYEN M,ARAGON E,PERRIN F X,et al.Effect of UV Aging on Electrochemical Behavior of an Anticorrosion Paint[J].Progress in Organic Coatings,2007,59(3):259-264.
[11]PERRIN F X,IRIGOYEN M,ARAGON E,et al.Artificial Aging of Acrylurethane and Alkyd Paints:A Micro-ATR Spectroscopic Study[J].Polymer Degradation&Stability,2000,70(3):469-475.
[12]ZOU F,THIERRY D.Localized Electrochemical Impedance Spectroscopy for Studying the Degradation of Organic Coatings[J].Electrochimica Acta,1997,42(20-22):3293-3301.
[13]KURZWEIL P,FISCHLE H J.A New Monitoring Method for Electrochemical Aggregates by Impedance Spectroscopy[J].Journal of Power Sources,2004,127(1-2):331-340.
[14]郑天亮,张华,王轩,等.用EIS法研究丙烯酸聚氨酯涂层的光老化性能[J].航空学报,2007,28(3):714-718.ZHENG Tian-liang,ZHANG Hua,WANG Xuan,et al.Research on the Photo-aging of Acrylic Polyurethane Coatings Using Electrochemical Impedance Spectroscopy[J].Acta Aeronautica et Astronautica Sinica,2007,28(3):714-718.
[15]曹楚南,张鉴清.电化学阻抗谱导论[M].北京:科学出版社,2002.CAO Chu-nan,ZHANG Jian-qing.An Introduction to Electrochemical Impedance Spectroscopy[M].Beijing:Science Press,2002.
[16]张鉴清.富锌涂层的电化学阻抗谱特性[J].中国腐蚀与防护学报,1996,16(3):175-180.ZHANG Jian-qing.On EIS Displays of Zinc Rich Coatings[J].Journal of Chinese Society for Corrosion and Protection,1996,16(3):175-180.
[17]张金涛.有机涂层中水传输与涂层金属失效机制的电化学研究[D].杭州:浙江大学,2005.ZHANG Jin-tao.Electrochemical Investigation on Water Transport Behavior of Organic Coatings and Degradation Mechanism of Coated-metals[D].Hangzhou:Zhejiang University,2005.
[2]罗振华,蔡键平,张晓云,等.耐候性有机涂层加速老化试验研究进展[J].合成材料老化与应用,2003,32(3):31-35.LUO Zhen-hua,CAI Jian-ping,ZHANG Xiao-yun,et al.Progress in Study of Accelerated Test for Anti-weathering Organic Coatings[J].Synthetic Materials Aging and Application,2003,32(3):31-35.
[3]林宏升,罗敏,陈宇豪,等.高耐候丙烯酸聚氨酯涂层的防腐蚀性能[J].材料保护,2015,48(9):47-49.LIN Hong-sheng,LUO Min,CHEN Yu-hao,et al.Anti-corrosion Performance of Highly Weather Resistant Acrylic Polyurethane Coating[J].Materials Protection,2015,48(9):47-49.
[4]杨丽霞,李晓刚,张三平.丙烯酸聚氨酯涂层在我国典型大气环境下的老化历程[J].环境技术,2006,24(6):19-22.YANG Li-xia,LI Xiao-gang,ZHANG San-ping.Aging Course of Acrylic Polyurethane Coating Exposed in Representative Atmosphere of Our Country[J].Environmental Technology,2006,24(6):19-22.
[5]卢琳,胡建文,李晓刚,等.光老化对丙烯酸聚氨酯/钢板界面附着力的影响[J].复合材料学报,2011,28(2):94-99.LU Lin,HU Jian-wen,LI Xiao-gang,et al.Effect of Photo Degradation on the Adhesion at Acrylic Polyurethane Varnish/Steel Interface[J].Acta Materiae Compositae Sinica,2011,28(2):94-99.
[6]MERLATTI C,PERRIN F X,ARAGON E,et al.Natural and Artificial Weathering Characteristics of Stabilized Acrylic-urethane Paints[J].Polymer Degradation&Stability,2008,93(5):896-903.
[7]耿舒,高瑾,李晓刚,等.丙烯酸聚氨酯涂层的紫外老化行为[J].北京科技大学学报,2009,31(6):752-757.GENG Shu,GAO Jin,LI Xiao-gang,et al.Aging Behaviors of Acrylic Polyurethane Coatings During UV Irradiation[J].Journal of University of Science and Technology Beijing,2009,31(6):752-757.
[8]李倩倩,李晖,郑会保,等.丙烯酸聚氨酯涂层万宁近海地区自然老化历程与机理[J].涂料工业,2016,46(3):12-18.LI Qian-qian,LI Hui,ZHENG Hui-bao,et al.Natural Aging Process and Mechanism of Acrylic Polyurethane Coating in Wanning Coastal Area[J].Paint&Coatings Industry,2016,46(3):12-18.
[9]王玲,高瑾,李晓刚,等.光辐射对丙烯酸聚氨酯涂层防腐保护性能的影响[J].北京科技大学学报,2008,30(2):152-155.WANG Ling,GAO Jin,LI Xiao-gang,et al.Effect of Photo-radiation on Anti-corrosion and Protection Performance of Acrylic Polyurethane Coating[J].Journal of University of Science and Technology Beijing,2008,30(2):152-155.
[10]IRIGOYEN M,ARAGON E,PERRIN F X,et al.Effect of UV Aging on Electrochemical Behavior of an Anticorrosion Paint[J].Progress in Organic Coatings,2007,59(3):259-264.
[11]PERRIN F X,IRIGOYEN M,ARAGON E,et al.Artificial Aging of Acrylurethane and Alkyd Paints:A Micro-ATR Spectroscopic Study[J].Polymer Degradation&Stability,2000,70(3):469-475.
[12]ZOU F,THIERRY D.Localized Electrochemical Impedance Spectroscopy for Studying the Degradation of Organic Coatings[J].Electrochimica Acta,1997,42(20-22):3293-3301.
[13]KURZWEIL P,FISCHLE H J.A New Monitoring Method for Electrochemical Aggregates by Impedance Spectroscopy[J].Journal of Power Sources,2004,127(1-2):331-340.
[14]郑天亮,张华,王轩,等.用EIS法研究丙烯酸聚氨酯涂层的光老化性能[J].航空学报,2007,28(3):714-718.ZHENG Tian-liang,ZHANG Hua,WANG Xuan,et al.Research on the Photo-aging of Acrylic Polyurethane Coatings Using Electrochemical Impedance Spectroscopy[J].Acta Aeronautica et Astronautica Sinica,2007,28(3):714-718.
[15]曹楚南,张鉴清.电化学阻抗谱导论[M].北京:科学出版社,2002.CAO Chu-nan,ZHANG Jian-qing.An Introduction to Electrochemical Impedance Spectroscopy[M].Beijing:Science Press,2002.
[16]张鉴清.富锌涂层的电化学阻抗谱特性[J].中国腐蚀与防护学报,1996,16(3):175-180.ZHANG Jian-qing.On EIS Displays of Zinc Rich Coatings[J].Journal of Chinese Society for Corrosion and Protection,1996,16(3):175-180.
[17]张金涛.有机涂层中水传输与涂层金属失效机制的电化学研究[D].杭州:浙江大学,2005.ZHANG Jin-tao.Electrochemical Investigation on Water Transport Behavior of Organic Coatings and Degradation Mechanism of Coated-metals[D].Hangzhou:Zhejiang University,2005.