Electroless Ni-Cu/PTFE Composite Coatings

Summary

A composile Ni-Cu-PTFE coaling was prepared by electroless plating. The composite consisted of 8.1 per cent PTFE, 60.8 per cent Ni, 21.1 per cent Cu and 10 per cent P by weight. DSC, X-ray, SEM and ESCA etc. were used to determine the structures and properties of the composite. The results show that the composite was composed of f.c.c. copper and an amorphous alloy of nickel and phosphorus, as-plated, with crystalline Ni₃P after heat-treatment. AES analysis indicated the proportions of Ni, Cu, P and F were 19.9: 16.1: 25: 39 on the surface of the composite. ESCA analysis showed further that copper and phosphorus were present as elements and P⁵⁺ on the composite surface and nickel existed in form of Ni₂O₃, and Ni²⁺, whereas fluorine and carbon existed in the form of PTFE. Tests proved that the composite of Ni-Cu-PTFE has good tribological properties. The composite wear is lower 26 per cent by weight than that of the coating of Ni-Cu-P in dry condition.