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In this study, the functionally graded Ni-P coatings with low phosphorus top most layers were deposited on the copper substrates by the electroless plating process. The surface morphology and cross-section observations were made by using scanning electron microscopy and optical microscopy. The results showed that electroless deposition of the Ni-P coatings with gradual change of phosphorus content led to a crack-free compact nodular morphology. Also, by using the graded Ni-P coatings, the wear and corrosion resistance were improved. The multilayer coating with the sequence of Ni-high P/Ni-medium P/Ni-low P layers from the substrate to the top surface exhibited the best wear and corrosion resistance.

The aim of the present study was to examine the feasibility of achieving a better combination of yield strength, ductility, and corrosion resistance of δ‐TRIP steel through the concept of microalloying. Three δ‐TRIP steels with different contents of Nb (0, 0.025, 0.076 wt%) were subjected to the microstructural, mechanical, and electrochemical examination. ASTM A283 and ASTM A516 steels were taken as comparative samples. The obtained results revealed a threefold increase in strength × ductility products of TRIP steels (35 255 MPa%) than comparative samples (12 760 MPa%) due to the TRIP effect and multiphase nature of the TRIP steel. The addition of Nb to the TRIP steel led to an unexpected decrease in the ultimate strength (from 1167 to 955 MPa) but an increase in ductility (from 30.21 to 31.78%) and corrosion resistance. The results of the electrochemical measurements showed that while A516 alloy exhibited the lowest corrosion resistance, the corrosion resistance of TRIP specimens was significantly increased by the addition of Nb which resulted in enhancement of the charge transfer resistance of the steel and indicates the superior corrosion resistance of the steel with 0.076% Nb.