CAJ | 학술논문

运用四种加速方法对聚氨酯有机涂层钢板进行老化，并通过涂层的表观性能和电化学特征对比研究了老化方式对涂层失效的影响.紫外老化对涂层光泽的影响最大，老化32 d失光度达85.7%.盐雾实验前期线性极化阻力Rp迅速下降，后期由于盐膜的生成使得Rp保持稳定；氙灯和盐雾混合老化的光泽度和Rp的变化规律都表现为实验前期与光老化相似，后期则与盐雾实验相类似.此外，拟合不同老化方式的电化学交流阻抗谱发现：混合老化前期主要受氙灯影响，与单一氙灯老化的等效电路一致，表现为两个时间常数；后期产生盐膜，出现三个时间常数.
운용사충가속방법대취안지유궤도층강판진행노화，병통과도층적표관성능화전화학특정대비연구료노화방식대도층실효적영향.자외노화대도층광택적영향최대，노화32 d실광도체85.7%.염무실험전기선성겁화조력Rp신속하강，후기유우염막적생성사득Rp보지은정；선등화염무혼합노화적광택도화Rp적변화규률도표현위실험전기여광노화상사，후기칙여염무실험상유사.차외，의합불동노화방식적전화학교류조항보발현：혼합노화전기주요수선등영향，여단일선등노화적등효전로일치，표현위량개시간상수；후기산생염막，출현삼개시간상수.
Four accelerated weathering tests were carried out on polyurethane coated steels. The apparent properties and electro-chemical characteristics of the coatings were studied to compare the effects of different accelerated weathering tests on the coating fail-ure behavior. It is found that UV exerts the greatest influence on the glossiness of the coatings and the gloss loss reaches up to 85. 7%after 32 d aging. The linear polarization resistance decreases rapidly in the early period of the salt spray test and stabilizes in the later period due to the formation of a salt film. In the mixed aging ( xenon light aging+salt spray) test, the variation tendency of both gloss loss and linear polarization resistance are similar to those presented in the early period of xenon light aging and similar to those presen-ted in the later period of salt spray test. Moreover, the equivalent circuit of the mixed aging test shows two time constants in the early period, which is consistent with the single xenon light aging test. In the later period, the failure process of the coatings can be mani-fested with three time constants, in which the formation of a salt film is the typical feature.