Corrosion Wear of TiN Ion Plated Alloy Tool Steel in a Sodium Chloride Aqueous Solution
Toshiyuki Tanaki, Makoto Yuasa, Isao Sekine
The corrosion wear of alloy tool steel (SKD 11) coated with TiN (Ti/TiN: single layer and Ti/TiN/Ti/TiN: multiple layers) was investigated in a NaCl solution in comparison with the case of mild steel (SS 400). Corrosion wear tests showed difference in morphorogy of damage between stators and rotors. In the stators, TiN films disappeared with a low load, and wear tracks were observed. As for the damage of rotors, the galvanic corrosion, the wear of substrates and the disappearance of TiN films occured under a load of 9.8MPa or below. With the highest load of 9.8MPa, the disappearance of TiN film, and the adhesion of wear debris and corrosion products were observed. It was found that the SKD 11 substrate was galvanically coupled with TiN films but the corrosion rate of the substrate was less than that of SS 400 by a factor of 2 or 3. The weight loss of SKD 11 with TiN films in corrosion wear tests was caused mainly by wear and partly galvanic corrosion.