颜料体积浓度对水在醇酸涂层中传输行为的影响

水、离子和氧气是导致涂层下金属发生腐蚀的三个重要因素，它们在涂层中的传输过程对其下面金属的腐蚀会产生较大的影响，研究它们在涂层中的传输过程对于弄清涂层下金属发生腐蚀的机制至关重要 .研究表明 [1－ 8]， 水在涂层中的传输是一个扩散过程，分起始和饱和两个阶段；在起始阶段，随研究体系和实验条件的不同，水在涂层中的扩散过程遵循不同的规律，可能满足菲克第二扩散定律，也可能会发生较大的偏差 .　　颜料与基料界面间的孔隙是水在涂层中传输的主要通道，调整颜料体积浓度（ PVC）可以改变涂层中这种孔隙的数量和分布，从而…

Effect of PVC on theDiffusing Behavior of Water through Alkyd Coatings

The diffusing behavior of water through alkyd coatings with different pigment volume concentration (PVC) has been studied by EIS and SEM techniques. The corresponding diffusion coefficients were also calculated. The experimental results showed that, in 0.5 mol· L－ 1 NaCl solution, the diffusion process of water through alkyd coatings with different PVC followed the ideal Fick′ s law in the initial period.Within the PVC value concerned, the diffusion coefficients initially decreased with the increase of PVC parameter, reaching a minimum value at 60 ％ , which is the CPVC of micaceous iron oxide, and then increased with the PVC increase. When the PVC was less than CPVC, the barrier property produced by the pigment was the main factor that affected the water diffusion behavior. However, the microstructure of the alkyd coatings played an important role when the PVC was greater than CPVC.