Abstract Silica deposition treatment (trade name: ITRO treatment) is a flame treatment process to form silica deposition on treated surfaces, and could be an innovative, rapid, automated, and clean alternative to reduce costs and hazardous chemicals for aircraft coatings. In this study, the bonding state and adhesion strength of aircraft coatings on an aluminum alloy following silica deposition treatment were evaluated. The chemical structure of the treated surface was examined using scanning electron microscopy and Fourier-transform infrared spectroscopy. The silica deposit consisted of aggregated nanoparticles and contained silica, silanol groups, and water. The amount of silica and silanol groups increased linearly with the number of treatments. The adhesion performance of the coating following the silica deposition treatment using pull-off testing revealed that one-time silica deposition treatment resulted in a high strength comparable to that achieved by anodizing treatments. Flame treatment without organosilicon compounds resulted in low adhesion strength, indicating that the presence of the silica deposit contributes to improving the adhesion strength. Cross-sectional observation of the coated substrate interface revealed that the aggregated nanoparticles formed a thin porous layer of several micrometers. The coating resin completely penetrated this layer, and mechanical interlocking between the silica deposit layer and coating resin was presumed to arise. The fracture surfaces from the pull-off tests revealed that fracture propagated within the silica deposit layer and that part of the silica deposit and coating resin adhered to the silica deposit remained on the substrates. It could thus be concluded that the silica deposit layer was the weakest link in the coated test pieces.

中文翻译：

---

2024铝合金的二氧化硅沉积处理以提高涂层附着力

摘要 二氧化硅沉积处理（商品名：ITRO 处理）是一种在处理过的表面上形成二氧化硅沉积物的火焰处理工艺，可以成为一种创新、快速、自动化和清洁的替代方案，以降低飞机涂层的成本和危险化学品。在这项研究中，评估了二氧化硅沉积处理后飞机涂层在铝合金上的结合状态和附着强度。使用扫描电子显微镜和傅里叶变换红外光谱检查处理过的表面的化学结构。二氧化硅沉积物由聚集的纳米颗粒组成并含有二氧化硅、硅烷醇基团和水。二氧化硅和硅烷醇基团的量随着处理次数线性增加。使用拉拔测试进行二氧化硅沉积处理后涂层的粘附性能表明，一次性二氧化硅沉积处理产生的高强度可与阳极氧化处理所达到的强度相媲美。没有有机硅化合物的火焰处理导致低粘合强度，表明二氧化硅沉积物的存在有助于提高粘合强度。涂层基材界面的横截面观察表明，聚集的纳米颗粒形成了几微米的多孔薄层。涂层树脂完全渗透该层，推测在二氧化硅沉积层和涂层树脂之间产生机械互锁。拉断试验的断裂面表明，断裂在二氧化硅沉积层内传播，部分二氧化硅沉积物和附着在二氧化硅沉积物上的涂层树脂保留在基材上。因此可以得出结论，二氧化硅沉积层是涂层试件中最薄弱的环节。