Industrial-scale high power impulse magnetron sputtering of yttria-stabilized zirconia on porous NiO/YSZ fuel cell anodes

Yttria-stabilized zirconia (YSZ) thin films are reactively sputter-deposited by high power impulse magnetron sputtering (HiPIMS) in an industrial setup on porous NiO/YSZ fuel cell anodes. The influence of deposition pressure, cathode peak power density, and substrate bias voltage on the deposition rate and film morphology is studied. It is seen that increasing the deposition pressure from similar to 370 mPa to similar to 750 mPa results in a 64% increase in the deposition rate and denser film. Films are deposited at peak power densities ranging from 0.4 kW cm(-2) to 1.1 kW cm(-2). By increasing the peak power density the degree of ionization of both Ar and sputtered metallic species is significantly increased which results in denser films as open column boundaries are removed. The increase in peak power also results in a considerable drop in deposition rate. By combining a peak power density of 0.6 kW cm(-2) with the application of -180 V substrate bias voltage a homogenous and essentially column-free coating can be deposited. These results demonstrate HiPIMS deposition as being capable of producing dense YSZ coatings on porous substrates as needed for solid oxide fuel cell applications. (C) 2015 The Authors. Published by Elsevier B.V.