Tribology and corrosion of Al-1.5wt.%Zn-5wt.%Sn ion platings

Al-Zn alloy coatings are superior to aluminium coatings in providing better galvanic corrosion resistance to steel components. In many applications, both good sacrificial corrosion protection and tribological properties are in question. In this work an attempt to improve the frictional characteristics of Al-1.5wt.%Zn alloy ion platings through introducing a small amount (5 wt.%) of a solid lubricant such as tin has been carried out. Tribological tests have shown a considerable improvement in the frictional behaviour caused by the microstructure of the Al-1.5wt.%Zn-5wt.%Sn alloy coatings which consists of an aluminium-rich phase surrounded by a continuous matrix of tin-rich phase. Corrosion tests have shown, however, a deteriorating effect on the corrosion tendency and corrosion rate of Al-1.5wt.%Zn coatings when tin is introduced into them.