Tungsten Carbide Nanoparticle Strengthened Tantalum Nanocoating for Engineered Gun Barrel Surfaces

US Army seeks innovative coating technologies for gun barrel surface applications to replace currently available highly toxic electroplated hard chrome. Cylindrical magnetron sputtered tantalum (Ta) coatings developed by US Army labs revealed some success in explosive bonding experiments, however, issues include cost and softness of the unalloyed Ta. Inframat proposes to fabricate a novel tungsten carbide (WC) nanoparticle strengthened Ta nanocoating via an environmentally benign co-electrodeposition process, where WC nanoparticles are co-deposited in a Ta matrix. The proposed program involves (1) preparing a colloidal bath composition containing WC nanoparticles in Ta solution, (2) depositing Ta-WC nanocoatings via IMC's proprietary co-electroplating process, and (3) evaluating coating properties. From our previous experience in electroplated WC/Co-Ni nanocoatings, we expect that the Ta-WC nanocoating will have significantly increased coating to substrate adhesion strength when compared with electroplated microsized hard chrome. The program is aimed to engineer the alloy hardness to a range compatible to hard chrome (850-1000 VHN). Since Ta and WC are high temperature materials, having melting points >3000oC, thermal mechanical fatigue and erosion wear properties are expected to outperform hard chrome coatings. The substitution of Ta with commercially available WC nanoparticles is expected to reduce cost of the alloyed Ta by 40%.