Zeolite as a wear-resistant coating

In searching for environmentally friendly alternatives to the widely used hard chrome and cadmium coatings, conventional wisdom has been focusing on materials with a high hardness that is usually provided by dense metals or ceramics, and inevitably accompanied by a high elastic modulus. A preferred wear resistant coating should have a high hardness but a relatively low modulus because a high modulus limits the coating's flexibility and overall wear performance. Here we show for the first time that zeolite materials, with their unique crystalline porous framework, possess this demanding balance. Zeolites' crystallinity offers an exceptional hardness while their porosity provides a relatively low elastic modulus. Zeolite coatings are demonstrated to outperform hard chrome and cadmium coatings in wear and corrosion resistance. (C) 2011 Elsevier Inc. All rights reserved.