Unraveling the Mechanism of the Conversion Treatment on Advanced High Strength Stainless Steels (Ahsss)

Regarding the environmental regulations in terms of greenhouse gas and fine particle emission, the automotive industry is looking for new solutions to reduce weight, improve safety performance and lower costs. one strategy is developing advanced high strength stainless steels (ahsss) which show a beneficial high strength to low thickness ratio. max1.2hy is a newly developed ferritic stainless steel grade that gains the martensitic phase after the hot stamping process. this material is dedicated to automotive structural parts and chassis parts [1][2]. the automotive industry takes advantage of a multi-layer coating in order to have optimal properties of the final product. as such, conversion coatings are chemically applied to metal parts before painting to improve corrosion protection and paint adhesion.  a conversion coating is a film formed during surface-based chemical reactions that include the base metal and other ions present in the solution. they can be classified based on the involved chemical reaction. one of the most industrially developed conversion treatments for the automotive car body is the phosphate conversion coating. according to the application of this grade of stainless steel in the automotive car body, it is crucial to examine its behavior in one of the main industrial steps, i.e., pre-treatment. in this study, the formation of an industrially applied phosphate conversion coating on the surface of this specific grade of stainless steel will be examined. in this regard, a new formation mechanism that is “preferential deposition” will be proposed for the formation of the phosphate conversion coating

Unraveling the mechanism of the conversion treatment on Advanced High Strength Stainless Steels (AHSSS)

Regarding the environmental regulations in terms of greenhouse gas and fine particle emission, the automotive industry is looking for new solutions to reduce weight, improve safety performance and lower costs. One strategy is developing Advanced High Strength Stainless Steels (AHSSS) which show a beneficial high strength to low thickness ratio. MaX1.2HY is a newly developed ferritic stainless steel grade that gains the martensitic phase after the hot stamping process. This material is dedicated to automotive structural parts and chassis parts [1][2]. The automotive industry takes advantage of a multi-layer coating in order to have optimal properties of the final product. As such, conversion coatings are chemically applied to metal parts before painting to improve corrosion protection and paint adhesion.  A conversion coating is a film formed during surface-based chemical reactions that include the base metal and other ions present in the solution. They can be classified based on the involved chemical reaction. One of the most industrially developed conversion treatments for the automotive car body is the phosphate conversion coating. According to the application of this grade of stainless steel in the automotive car body, it is crucial to examine its behavior in one of the main industrial steps, i.e., pre-treatment. In this study, the formation of an industrially applied phosphate conversion coating on the surface of this specific grade of stainless steel will be examined. In this regard, a new formation mechanism that is “preferential deposition” will be proposed for the formation of the phosphate conversion coating