Corrosion Resistance of Amorphous-Nanocrystalline Composite Structure Materials

The purpose of this paper is to investigate the corrosion resistance of different nanoscale microstructures in the same material system and propose a novel method to obtain high-performance materials. During the last 2 decades, microstructure refinement and microalloying have become the main methods to prepare high-performance materials. The tensile strength of nanocrystalline solid solutions can reach 2.3 gigapascal, which is more than 1 fold the strength of traditional steel. However, there are few studies about the corrosion resistance of different nanoscale microstructures. In this paper, coatings with different microstructures (nanocrystalline, amorphous, and amorphous-nanocrystalline composite) have been successfully prepared by electrodeposition in the same material system (nickel-phosphorus alloy). Electrochemical test and high-pressure corrosion immersion test were carried out. The results show that the material loss of amorphous-nanocrystalline coating (P = 9.2 wt %) is about 1/4 that of crystalline coating at 8 MPa. In the range of 0.1 and 8 MPa, the average acceleration effect of hydrostatic pressure on the corrosion rate was calculated to be 1.611 × 10^-6 g·cm^-2·d^-1·MPa^-1.