Microstructural Study of a Zn-Ni Alloy Prepared by Ball Milling Using Two Different Devices

Abstract

Metallic zinc (Zn) has ben extensively used as protective coating of iron and steel for decades, but problems related with its high permeability has reduced its application. It was found that the corrosion resistance of zinc in form of alloys is increased by adding some transition metals. Recently, the Zn-Ni system is under research as an efficient alternative as anticorrosion coating for metals. Zn-Ni is mostly prepared by electroplating or thermal spray technologies, but there are some problems like: (i) fluctuation of Zn-Ni contents, (ii) the pollution caused by plating solutions and (iii) irregular thickness of the coating. The mechanical alloying (MA) technique can be used to fulfill the above issues because this route facilitates the synthesis of homogeneous materials from powder mixtures . Also, MA is frequently employed for the preparation of new materials based on mechanochemical reactions performed at room temperature, while avoiding the conventional ingot metallurgy [3]. This work deals with the preparation and study of a Zn-Ni alloy prepared by MA using two types of milling devices: a planetary which works manly through abrasion and impact of grinding balls and the Spex which works through the high-energy impact of balls. Zn-Ni was prepared from pure Ni and Zn powders, the equiatomic compositions were weighed and milled for 4 hours followed by sintering at 357°C during 1h.