Mixing of graphene nanoplatelets with magnesium alloy powders by electrostatic adsorption

Abstract

Mg matrix composites reinforced by graphene nanoplatelets (GNPs) offers an efficient approach for improving the mechanical properties of Mg alloys. Unfortunately, the poor uniform dispersion of GNPs into Mg matrix vastly restricts their development. In addition, surface oxidation of Mg alloy powders is always serious. To alleviate these issues, pickling and surface modification technologies of ZK61 Mg alloy powders and mixing process with GNPs have been investigated. The results show that ZK61 alloy powders with smooth surface and low degree of oxidation can be obtained after being simultaneously mechanically stirred and ultrasonically treated for 30 min in a 0.2 vol% HF ethanol solution. They were then rinsed and dried, and modified by 0.3% wt% cetyl trimethyl ammonium bromide to carry a positive charge. Subsequently, GNPs ethanol suspension was poured into the modified ZK61 alloy powders solution and mechanically stirred for 10 min, and then a powder mixture that GNPs randomly attached on the Mg powders was obtained after drying.XPS analysis reveals that GNPs were adsorbed on the surfaces of the modified Mg powders by the mechanism of electrostatic adsorption. The achieved method for preparing GNPs/ZK61 alloy mixture powders provides a new strategy for fabricating Mg matrix composites reinforced by uniformly distributed GNPs.