Investigation of hybrid Zr-aminosilane treatment formation on zinc substrate and comparison to advanced high strength stainless steel

This research investigates the deposition mechanism of a hybrid Zr-aminosilane conversion coating as a replacement for the conventional pretreatment systems on a zinc substrate. The traditional Zr-based conversion treatment has been optimized by the addition of both Cu as an accelerator and aminosilane as an adhesion promotor. The deposition mechanism was unraveled using complementary surface analytical techniques such as XPS, FEG-AES, EDX, GDOES, and ToF-SIMS. The results showed the addition of aminosilane has resulted in the incorporation of N into the Zr oxide layer. This suggests that the influence of aminosilane is not only on the top surface, as an adhesion promoter, but also on the chemistry of the deposited layer. Additionally, the properties of this pretreatment on zinc is compared to Advanced High Strength Stainless Steel (AHSSS) as another automotive material. This was done in order to compare the behavior of active and passive substrates in the same conversion treatment. This comparison shows that zinc as an active material can show higher interaction with the conversion treatment which results in a ticker film formation.