Variation of the lead content in sputtered copper–lead films due to resputtering effects

Soft tribological coatings deposited by magnetron sputtering are used as protective layers of sliding bearings in high‐performance diesel engines. They consist of a tough component with a high melting point and a soft component with a low melting point. The tough component gives mechanical stability while the soft component provides the capability to embed contamination particles. The components are immiscible to prevent the formation of intermediate brittle phases. One system under investigation is copper lead. Although the chemical composition of a sputter‐deposited film should generally be equal to target composition this does not hold for Cu with a small amount of Pb. The experiments showed that the Pb content of films deposited by magnetron sputtering with Ar+ ions from a planar‐cast Cu 4 wt % Pb target strongly depends on the process parameters of working gas pressure and substrate temperature. Gas pressure and substrate temperature were varied from 0.3 to 5 Pa and 100 to 260 °C, respectively. The P...