铝合金型材粉末喷涂前处理工艺综合比较分析

Comprehensive Comparative Analysis of Pretreatment Processes for Powder Spraying of Aluminum Alloy Profiles

摘要:

探讨了铝型材粉末喷涂前处理的不同方法，主要涉及酸性除油和碱性除油及无铬钝化和有铬钝化方法。通过比较刻蚀量、钝化膜膜重、耐酸碱腐蚀试验和砂浆腐蚀试验等方面的综合数据，评估了不同前处理工艺的效果，并利用扫描电子显微镜（SEM）、能量色散X射线光谱（EDS）对经前处理后铝型材的表面微观形貌和元素组成进行了初步分析。值得注意的是，进行了48 h的酸碱浸泡腐蚀试验和1个月的砂浆模拟腐蚀试验，这些试验是在现行国标GB/T 5237.4-2017检测方法基础上进行的，显示出超越国标的腐蚀破坏性，以快速区分不同前处理工艺的耐蚀性优劣。结果表明，不同前处理工艺对粉末涂层的耐蚀性有显著影响，其中酸性除油和有铬钝化工艺表现出最佳的耐腐蚀性能，其次是酸性除油和无铬钝化工艺，最后是碱性除油和无铬钝化工艺。

Abstract:

The pretreatment process of aluminum profile powder spraying involves two main approaches for oil removal， i.e. acidic and alkaline oil removal. Additionally， passivation can be achieved through chromium free passivation and chromium passivation. This study conducts a comprehensive comparison of various pretreatment processes， considering factors such as etching amount， passivation film weight， acid alkali corrosion resistance， and mortar corrosion resistance. Surface micromorphology and elemental composition of the pretreated aluminum profiles were analyzed using SEM and EDS. Notably， this research introduces novel testing methods， including a 48-hour acid and alkali immersion corrosion test and a 1-month mortar simulated corrosion test， surpassing the current national standard GB/T 5237.4-2017. These tests effectively differentiate the corrosion resistance performance among different pretreatment processes. The results indicate that the corrosion resistance of powder coatings is influenced by the chosen pre-treatment processes. The combination of acid oil removal and chromium passivation processes demonstrates the highest corrosion resistance， followed by acid oil removal with chromium free passivation. Alkaline oil removal with chromium-free passivation exhibits the least corrosion resistance among the tested processes.