The behavior of electroplated hard-chromium on Cr–Mo steel subject to long-term annealing at 250°C

Huang, Ching An; Li, K.C.; Lin, Weitao; Liao, Ming‐Feng

doi:10.1016/j.msea.2005.05.007

Cited by 14 publications

(3 citation statements)

References 7 publications

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“…Consequently, the applied layers achieve a hardness of 52% of hard chrome. The crystallite size of electroplated hard chrome is between 50 and 200 nm [23]. In the literature you can find a crystallite size of 20-25 nm for Fe-Cr-Ni layers [5].…”

Section: Hardness and Wear Resistancementioning

confidence: 99%

Electrodeposition of Thick and Crack-Free Fe-Cr-Ni Coatings from a Cr (III) Electrolyte

et al. 2022

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The electrodeposition of iron-nickel-chromium coatings is a more environmentally friendly and economical alternative to hard-chrome coatings made from chromium (VI) electrolytes and stainless-steel bulk materials. The aim of the study was to develop a suitable deposition method for thick and low-crack Fe-Cr-Ni coatings. Iron-nickel-chromium coatings were electrodeposited using a more ecological chromium (III) electrolyte with direct current (DC), stepped direct current, and pulse current (PC). The influence of the deposition method on the electrolyte aging, the alloy composition of the coating, and their microstructure was investigated. Corrosion studies of the Fe-Cr-Ni coatings in 3.5% NaCl solution were performed using polarization tests. Furthermore, hardness measurements and scratch tests were carried out to determine the adhesion strength. Phase analyses were performed by X-ray diffraction, and the chemical composition and microstructure were characterized by scanning electron microscopy. Using the stepped DC and PC method, crack-free Fe-Cr-Ni coatings were successfully deposited.

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Section: Hardness and Wear Resistancementioning

confidence: 99%

Electrodeposition of Thick and Crack-Free Fe-Cr-Ni Coatings from a Cr (III) Electrolyte

et al. 2022

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“…During the long period of thermal aging, recovery, recrystallization, and grain growth occurred in the Au-Ni coating. Boundary migration occurred simultaneously, and these pores were probably formed among the grain boundaries owing to discontinuities of boundary movement [23,24]. As these pores were extremely small in size, they did not have any obvious effects on the electrical and tribological performances of the coating.…”

Section: Sem Observations and Interferometric Study Of Surface Morphomentioning

confidence: 99%

Characterizations of thermal stability and electrical performance of Au-Ni coating on CuCrZr substrate for high vacuum radio-frequency contact application

et al. 2018

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Radio-frequency (RF) contacts-which are an example of electrical contacts-are commonly employed on accelerators and nuclear fusion experimental devices. RF contacts with a current load of 2 kA for steady-state operation were designed for application to the International Thermonuclear Experimental Reactor (ITER) device. In contrast to the typical working conditions of general commercial electrical contacts, those of RF contacts employed on fusion devices include high vacuum, high temperature, and neutron radiation. CuCrZr is currently of interest as a base material for the manufacture of louvers of RF contacts, which has excellent thermal and electrical properties and has low creep rate at 250 °C. In this study, a hard Au coating (Au-Ni) was electroplated on CuCrZr samples and the samples were then subjected to thermal aging treatment at 250 °C for 500 h in order to simulate the vacuum-commissioning process of the ITER. The effects of thermal aging on the hardness, elastic modulus, crystallite size, and compositions of the coating were investigated via microstructural and mechanical characterizations of the coating material. Metal atom migration in different coating layers during thermal aging was characterized and evaluated via scanning electron microscopy/energy dispersive X-ray spectroscopy observations of the cross-sectional surfaces, and the obtained results could be used to directly select the coating thickness for the final RF contact component. The contact resistance-an important parameter of the RF contact-was measured in a dedicated testbed built to simulate fusion reactor conditions between CuCrZr pins and stainless steel plates coated with Au-Ni and Rh, respectively.

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“…Although being notable for its high hardness and excellent wear resistance, Chromium electroplating has micro-cracks which act as the passage for the corrosion agents to pass through to the substrates, resulting in the decrease of the corrosion resistance [1][2][3][4][5]. The decrease of the hardness at high temperature also limits its application [1,4,6]. To form Chromium nitrides on the coating is one of the possible solutions to these problems.…”

Section: Introductionmentioning

confidence: 99%

Effect of Rare Earth Addition in Plasma Nitriding on Microstructure of Chromium Electro-Plating

Huang

Xiong

Fan

2010

AMR

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As an active metal, chromium is easy to form oxides film on the surface, which acts as an obstacle to the nitrogen diffusion in plasma nitriding. Rare earth (RE) was introduced into the conventional plasma nitriding (CPN) to improve the nitriding behavior. Chromium coatings were treated by CPN and rare earth plasma nitriding (REPN) at 620°C for 5 and 10 hours respectively. Comparative study showed that the addition of RE prompted greatly the formation of higher nitrogen containing phase CrN, rather than Cr2N. It created a crack-free, much denser and thicker nitrides layer, which contributed to the increase of hardness. The dynamic ultra micro hardness of the samples treated by REPN was nearly 1600GPa, which was much higher than the original and the CPN treated samples. The conclusion could be drawn that compared to CPN, REPN are more efficient for chromium coating nitriding.

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The behavior of electroplated hard-chromium on Cr–Mo steel subject to long-term annealing at 250°C

Cited by 14 publications

References 7 publications

Electrodeposition of Thick and Crack-Free Fe-Cr-Ni Coatings from a Cr (III) Electrolyte

Electrodeposition of Thick and Crack-Free Fe-Cr-Ni Coatings from a Cr (III) Electrolyte

Characterizations of thermal stability and electrical performance of Au-Ni coating on CuCrZr substrate for high vacuum radio-frequency contact application

Effect of Rare Earth Addition in Plasma Nitriding on Microstructure of Chromium Electro-Plating

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