钛/锆钝化膜烘干温度对有机涂层结合强度的影响

The Effect of Ti/Zr Conversion Coating Drying Temperature on the Adhesive Strength of Organic Coating

本文考察了钛/锆钝化膜烘干温度对有机涂层结合强度的影响,并对结合机理进行了初步探讨。以六氟钛酸和六氟锆酸为钝化液的主要成分对6063铝合金表面进行钛/锆钝化处理,经不同温度的烘干处理后进行静电粉末喷涂。利用扫描电子显微镜(SEM)、漆膜冲击试验机和划格仪等分析了钝化膜喷涂前后的微观形貌及有机涂层结合强度。结果表明成膜时间为60 s获得的钛/锆钝化膜表面平整致密。钛/锆钝化膜的最佳烘干温度为100~110℃。膜层烘干温度过低,膜层表面会因水分子残留形成气泡,降低与有机涂层的附着力;烘干温度过高,会使膜层表面的微裂纹变宽、数量增加,降低与有机涂层的附着力。

This study investigates the effect of the Ti/Zr conversion coating drying temperature on the adhesive strength of organic coating and discusses the adhesive mechanism between the conversion coating and epoxy coating. The AA6063 substrates were treated in fluotitanate and fluozirconate-based conversion solution at room temperature. The organic coating was applied on samples using electrostatic spraying after different drying temperatures. The surface morphology and chemical composition of different samples were investigated using scanning electron microscope(SEM). The adhesive strength of organic coating on the treated AA6063 was studied using tape adhesion measurement and impact testing, respectively. Results showed that the Ti/Zr conversion coating formed at 60 s had a uniform structure. The temperature period of 100~110 ℃ was the optimal drying temperature for adhesion property. The water remained on the conversion coatings would decrease the adhesive strength when the drying temperature was under 100 ℃. The cracks of the conversion coatings surface caused by internal stress would become more broader when the drying temperature exceeded 110 ℃ and thus decreased the adhesive strength.