The corrosion resistance of FeCoNiCr high-entropy alloy deposits was investigated upon being prepared by current electrodeposition. The coatings were co-deposited in an electrolyte of an aqueous ferrous, cobalt, nickel, and chromium sulfates solution. Energy dispersive spectrometry analysis demonstrated that all four elements were co-deposited successfully. At the same time, the results from SEM indicate that the surface of the coating exhibits a granular morphology, with uniform density and no presence of cracks, with sizes ranging from 500 nm to 5 μm. Furthermore, X-ray diffraction patterns enunciated that the as-deposited coatings were amorphous. The polarization curves of the FeCoNiCr high-entropy alloy coating were measured by an electrochemical workstation in 3.5 wt.% NaCl, 1 mol·L⁻¹ H₂SO₄ and 1 mol·L⁻¹ NaOH solutions. The results revealed that the coating exhibited excellent corrosion resistance. The corrosion mechanism of the FeCoNiCr high-entropy alloy coating was analyzed in different environments. Moreover, the scratch testing method was employed to determine the alloy adhesion on the substrate, with higher values obtained for the FeCoNiCr alloy.

In this paper, nickel-based alloy coatings were deposited on the surface of pure copper by jet electrodeposition. The wear resistance of the coatings was studied by a material surface comprehensive performance tester under dry sliding. Hardness testing, friction, and wear testing were performed to characterize the microhardness, surface morphology, and wear resistance of the coatings. The results indicated that adding Fe and W could refine and purify the microstructure. The coatings with additions of 5 wt.% Fe and 7 wt.% W exhibited the highest wear-resistant properties. Moreover, new compound phases NiO, Fe₂O₃, and WO₃ were found on the surface coatings, such that the microhardness was higher than that in the other coatings. Detailed discussions on the influences of Fe and W on the sliding wear are presented.

The undercooling of pure aluminum melt was in situ investigated by differential scanning calorimeter with flux processing technique in this study. The highest undercooling of pure aluminum with 17.8 K was obtained as the thermal treatment temperature of the melt being 1033 K and the cooling rate being 50 K min⁻¹. When cooling rate is fixed, the undercooling depends on the melt processing temperature, and increases rapidly at the first stage. The effects of thermal treatment temperature and cooling rates on the undercooling are discussed in this article.

The effect of Nb alloying on the suppression of austenite grain coarsening behavior during pseudo–carburizing is investigated in high–temperature–carburized SAE4320 bearing steel. To explore the role of the Nb element in the pseudo–carburizing process, the morphology, composition, size, and distribution of NbC precipitates were analyzed. The results show that the fine austenite grain observed in Nb micro–alloyed steel is caused by the pinning effect of NbC precipitates, which hinders the coarsening of austenite grains and changes the growth dynamics of austenite grains. After the SAE4320 carburized bearing steel with the addition of 0.45 wt.% Nb element is kept at 1150 °C for 4 h, the PAG size is still below 20 μm, which indicates the Nb element has obvious advantages in limiting PAG growth at high temperatures and shows great potential for the development of high–temperature carburized bearing steel.