Zinc chloride hydroxide - A recyclable diffusion source for fabrication of zinc rich coatings on magnesium alloys

Abstract

To reduce greenhouse gas emissions and fuel consumption, it is important to utilize lighter materials in vehicles. Magnesium is the lightest structural metal, but the corrosion resistance of magnesium and magnesium alloys is limited. The powder thermal diffusion alloying method can enhance the surface of magnesium alloys by fabricating a metallic coating. The huge consumption of powders and potential environmental pollution problems should be controlled for the sustainable development of related industries. Here, based on the investigation of the evolution of a diffusion source in powder thermal diffusion alloying processes, we propose a recyclable diffusion source that can be utilized in a series of diffusion alloying processes without reloading a new diffusion source or the addition of other powders. This diffusion source is mainly based on reversible chemical reactions related to zinc hydroxide chloride. With such a recyclable diffusion source, diffusion alloying processes can be carried out more fluently, and the powders can be saved effectively. Meanwhile, both the environment and the health of workers can be protected. It is our hope that this idea could inspire traditional pack cementation industries to find similar resource-conserving and environmentally friendly approaches. Meanwhile, widespread application of both magnesium alloys and zinc hydroxide chlorides can be promoted.