Higher performance is steadily required in the field of material surface engineering, especially in terms of surface degradation of mechanical parts and repair and renewal of surfaces. By preparing a more reasonable surface design and improving the surface composition and structure of the material, the surface modification layer can provide an important potential solution to the surface degradation problem. The coatings obtained by double glow plasma surface alloying (DGPSA) technology are a compelling method in current and future applications because of a unique combination of characteristics including pollution-free, the gradient distribution of the alloying elements and the strong metallurgical bonding between the alloying layer and the matrix. In recent years, with the increasing requirements for the surface properties of materials in various environments, the layer prepared by DGPSA technology is developing toward alloying, functionalization and nanometer. This review begins with a brief introduction of double glow plasma surface alloying. The recent developments of the double glow plasma surface alloying technology for improving various surface performance are systematically reviewed in the sight of applied material, background, duplex treatment and duplex coating preparation.

Recent developments in research of double glow plasma surface alloying technology: a brief review

Electrodeposition of Ir–Co thin films on copper foam as high-performance electrocatalysts for efficient water splitting in alkaline medium

Anodic dissolution characteristics of Inconel 718 in C6H5K3O7 and NaNO3 solutions by pulse electrochemical machining

Nanocrystalline nickel coatings were electroplated from a Watts-type bath with the addition of H3BO3 ranging of 5–25 g·L−1. In order to study the evolution of preferential orientation of Ni electrodeposits, the microstructure, texture and grain size of the coatings deposited with different H3BO3 contents for different plating times were characterized by optical microscopy, scanning electron microscopy and X-ray diffraction, further the residual stress, microhardness, and abrasion resistance of the texture-oriented coatings were measured by X-ray diffraction, Vickers microhardness tester, and Calotester, respectively. The electrochemical corrosion resistance of the highly texture-oriented coatings and the substrate was evaluated by polarization and electrochemical impedance spectroscopy. The results show the preferential orientation of the coating was gradually changed from (200) to (220) crystal plane with increasing H3BO3 content after plating time of 1 h. The longer the plating time was applied, the higher the degree of Ni (200) orientation was produced at a low H3BO3 concentration of 5 g·L−1. The preferential orientation of the coatings at a high H3BO3 concentration of 25 g·L−1 was changed initially from (111) + (200) to (200) plane, then random orientation, and evolved to (220) plane after plating time of more than 20 min. The stability of various textures of Ni electrodeposits against plating time-H3BO3 concentration was established, and at the same time the microstructure-property relationship was developed. The average grain size of nickel coating was about 50–65 nm. The average residual stresses of the coatings with (200), (200) + (220) and (220) orientations were −64.3 ± 5 MPa, −477.2 ± 57 MPa and −618.0 ± 36 MPa, respectively. The microhardness of the coating increased gradually from 242.52 ± 10HV1 to 269.46 ± 12HV1 with increasing H3BO3 content because of the inverse Hall-Petch and grain orientation. The abrasion and corrosion resistances of (200)-oriented coatings were better than those of (220)-oriented coatings.

Texture orientation, morphology and performance of nanocrystalline nickel coatings electrodeposited from a Watts-type bath: Effects of H3BO3 concentration and plating time

Electrodeposition of nickel-iridium alloy films from aqueous solutions

Microstructure evolution and austenite stability of a Fe-6.0Mn-0.2C-1.0Al-0.05Nb-0.20Mo alloy fabricated by a novel cyclic quenching treatment were investigated. According to the experimental results, the influences of cyclic quenching treatment on retained austenite could be described as follows: (1) turning austenite grain morphology from a mixture of lamellar and equiaxed grain to the lamellar grain with the increase in cyclic quenching passes, (2) increasing austenite stability for the grain refinement (up to 0.21μm) and higher C/Mn content in austenite. In addition, cyclic quenching treatment can increase the yield strength (YS), ultimate tensile strength (UTS) and total elongation (TE) of the experimental steel up to 172 MPa, 89 MPa and 8%, respectively. The average product of UTS and TE of the experimental steel after cyclic quenching treatment could reach up to 66.6 GPa·%. Moreover, the yield point elongation increased with the increase in cyclic quenching passes.

Microstructure evolution and enhanced mechanical properties of a Nb–Mo microalloyed medium Mn alloy fabricated by a novel cyclic quenching treatment

The influence of intercritical annealing plus tempering treatments on the microstructure and mechanical properties of a novel Nb–Mo bearing medium Mn steel was investigated in this work. Based on the experimental results, the microstructure of experimental steel affected by intercritical annealing plus tempering treatments could be included as follows: (1) the retained austenite (RA) fraction fluctuated slightly (~41%) when the samples tempered between 150 °C and 350 °C, then decreased up to 32% at 450 °C for the austenite decomposition; (2) RA mechanical stability increased with the increase in tempering temperatures; (3) (Nb,Mo) (C,N) precipitates density increased from 150 °C to 450 °C by decreasing mismatch degree between precipitates and ferrite; (4) the coarsening rate of (Nb,Mo) (C,N) precipitates decreased from 150 °C to 450 °C, which led to a decrease in mean size of precipitates. The increase in tempering temperatures from 150 °C to 450 °C led to the yield strength increasing from 581 MPa to 765 MPa. The total elongation increased from 29% to 37% with the tempering temperatures increased from 150 °C to 350 °C, then decreased up to 25% at 450 °C.

Microstructure and mechanical properties of a novel Nb–Mo bearing medium-Mn alloy affected by intercritical annealing and tempering

The invention relates to a light metal-base laminar composite and a preparation method. The light metal-base laminar composite contains laminar light metal and graphene nanosheets distributed in the laminar light metal and is characterized by comprising at least two heterogeneous light metal base plate metal layers and at least one composite layer which are arranged alternately, wherein the composite layer is located between the two heterogeneous light metal base plate metal layers; the light metal-base laminar composite is prepared through cold rolling, warm rolling, hot rolling, electro-plastic rolling or combined warm rolling and electro-plastic rolling. The light metal-base laminar composite prepared with the method has higher toughness, large-scale production of large-size laminar composite boards can be realized, a process is simple, and the cost is relatively low.

Light metal-base laminar composite and preparation method thereof

Nickel–iridium (Ni–Ir) alloy system is of great interest for catalytic and corrosive environment applications. In this study, Ni-Ir alloys were galvanostatically electrodeposited on copper substrates from citrate aqueous solutions in a three-electrode cell system. The effects of deposition variables, including pH, temperature and current density, on the faradaic efficiency (FE), chemical composition, surface morphology and crystallographic structure of the films were studied. The electrochemical behaviors of Ir, Ni and co-deposited alloys were investigated using cyclic voltammetric, chronopotentiometric and chronoamperometric techniques. The results show that Ni–Ir alloys as thick as 25.7 μm with Ir–content as high as 15 at% and the FE as high as 36% were obtained. By adjusting these deposition parameters, the optimum pH, temperature and current density for deposition of Ni-Ir alloys were 5.0, 70°C and 60 mAcm−2, respectively. As the deposition variables were varied, the abundant of Ni-content in the deposit was obtained. The alloy was composed of nanocrystalline phase. The deposition of Ni ions was favored, and the co-deposition of Ni-Ir alloy was a normal deposition. The chronoamperometric transient nucleation at the potentials of −0.25 and −3.0 V were consistent with the model of diffusion-controlled 3D nucleation.

Zhizhi Wang

Papers

Electrodeposition of nickel-iridium alloy films from aqueous solutions

Microstructure evolution and enhanced mechanical properties of a Nb–Mo microalloyed medium Mn alloy fabricated by a novel cyclic quenching treatment

Microstructure and mechanical properties of a novel Nb–Mo bearing medium-Mn alloy affected by intercritical annealing and tempering

Light metal-base laminar composite and preparation method thereof

Effect of Electroplating Variables on Electrodeposition of Ni Rich Ni-Ir Alloys from Citrate Aqueous Solutions