Corrosion protection mechanisms of TiMgN hard coatings on steel

20th Chemnitz Seminar on Materials Engineering - 20. Werkstofftechnisches Kolloquium

Heyn, A.^1 ; Mueller, T.^2 ; Balzer, M.^3 ; Kappl, H.^3 ; Fenker, M.^3

Otto-von-Guericke-University Magdeburg, Institute of Materials and Joining Technology, Magdeburg, Germany^1

Bundesanstalt für Materialforschung und -prüfung, Division 7.6 Corrosion and Corrosion Protection, Berlin, Germany^2

Forschungsinstitut Edelmetalle + Metallchemie, Schwäbisch Gmünd, Germany^3

关键词: Analytical studies;    Application range;    Corrosion property;    Corrosion protection mechanisms;    Low alloyed steels;    Magnesium hydroxide;    Physical vapor deposited;    Positive impacts;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/373/1/012009/pdf
DOI  :  10.1088/1757-899X/373/1/012009

来源: IOP

【 摘 要 】

Hard coated steel components are used in a wide application range, mostly for protective, wear resistant and decorative purposes. Despite of these coatings being regarded as relatively dense, there is always a high risk of localized corrosion when a coated low alloyed steel component encounters a surrounding high humidity atmosphere or even an aqueous medium. An approach to enhance the corrosion properties is the addition of magnesium to physical vapor deposited hard coatings, like TiN. It has been found that there is a remarkable increase in corrosion resistance in dependence of magnesium content of the TiMgN coating and its surface properties. In this work the authors will explain the underlying corrosion protection mechanisms by means of electrochemical and analytical studies. The positive impact of magnesium in the coating relates on its preferred dissolution vs. steel. This causes the potential to shift to more negative direction with respect to the steel substrate and additionally leads to a temporarily passivation of the steel due to alkalization of the surrounding electrolyte by formation of magnesium hydroxide.