COLD SPRAYED COATINGS WITH DUAL NANOPARTICLE REINFORCEMENTS FOR WEAR AND CORROSION PROTECTION

Abstract

As a form of additive manufacturing, the use of cold spray has made significant strides since different-sized particles were explored in the process. There is proof that micron-sized particles down to nanoparticles enhance the mechanical material properties of a substrate in wear resistance. Micron- and submicron-sized particles are beneficial, but due to their low relative surface areas, they tend to exhibit pull out more often and do not adhere to a substrate as well as a nanoparticle. Using nanoparticle metal and dual ceramic matrix reinforcements, six composites were fabricated through cryomilling and then applied to an aluminum substrate as a cold sprayed coating. Using nano-boron carbide (nB4C) and boron nitride nanoplatelets (BNNP) at various combinations up to 2 vol%, an increase of 11.59% in hardness from the control was achieved. Wear testing of each coating was performed, but most of the tests drove through the coatings into the substrate, indicating more refinement of the testing parameters is required. Additionally, corrosion testing was performed on cold sprayed samples for 500- and 2,000-hr trials in a salt fog chamber, revealing underlying pitting corrosion and galvanic corrosion vulnerabilities of the coatings. In the right application, the U.S. Navy could potentially use these coating materials in parts that are subjected to austere marine environments.