XPS and SIMS study of the ageing mechanism of Zr–V non-evaporable getter films

Thin films of the Zr–V getter alloy were prepared on stainless steel substrates using magnetron sputtering. The getter surface chemical composition was investigated by X-ray photoelectron spectroscopy (XPS) for four air exposure/activation cycles. The experimental results show the decrease of the activation capacity after several oxidation/activation cycles. The adsorbed carbon is transformed simultaneously to zirconium and vanadium carbides, which are inactive for both oxidation and reduction processes. Higher affinity of V to carbon atoms was confirmed by secondary ion mass spectroscopy (SIMS) study of CO adsorption.