TRIBOLOGICAL AND CORROSIVE CHARACTERISTICS OF ELECTROCHEMICAL COATINGS BASED ON COBALT AND IRON SUPERALLOYS

摘要

The tribological and corrosive characteristics of binary and ternary alloys electrodeposited from CoW, FeW, CoMoP, and CoWP citrate solutions are studied. The tungsten content of CoW alloys reaches 31 at. percent and of FeW alloys 34 at. percent. The introduction of phosphorus into the alloys reduces the content of tungsten from 26.7 to 19.7 at. percent (at 4.5 at. percent P). The molybdenum content of CoMoP alloys is 0.7-1.0 at. percent at 5 to 8 at. percent P. The electrolytic tungsten alloys are nanocrystalline and subgrains are 4 to 7 nm in size. The nanohardness of tungsten-rich alloys (~13 GPa) is comparable with that of electrolytic chromium coatings. The wear resistance of the deposited alloys is quite high and is commensurable with that of hard coatings such as TiB_2, TiN, and TiAlN. The tribooxidation of FeW alloys in dry friction is revealed. The corrosion resistance of the coatings is similar to that for electrolytic chromium.