Deposition of Fe–C alloy on structural steel and cast iron for repair of worn machine parts

Abstract

Baths have been investigated for electrodeposition of Fe–C alloy on structural steel and cast iron with the aim to repair worn machine parts. Baths are FeSO 4-based and contain asparaginic, succinic, or ascorbic acid as additives. The deposits obtained have been compared with respect to their hardness, wear and corrosion resistance, and adhesion. The influence of plating variables (bath pH value and temperature, current density) on current efficiency and mechanical properties of deposits obtained have been investigated for a bath containing asparaginic acid and for a bath (known from literature) containing succinic acid as a basis for comparison. Coatings with 0.35–0.75% C content, micro-hardness of 600–710 HV (with 50 gf load), corrosion rate of 0.0560–0.0715 mm year −1 and good wear resistance and adhesion have been found at relatively high current efficiency (90–95%) and rate of deposition (45–50 μm h −1) and at relatively moderate plating conditions (about 50°C and 3.5–4.0 A dm −2, bath pH=2.5). Deposits from a bath with asparaginic acid have shown a somewhat higher hardness and corrosion resistance and can be obtained at lower temperature compared with deposits from a bath with succinic acid. Thick and multi-layer deposits with good mechanical and anticorrosive properties can be obtained at high current efficiency from baths containing asparaginic or succinic acid. Both baths are stable, with good covering ability and throwing power.