Fabrication of Co-W Alloy/Multiwalled Carbon Nanotube Composite Films by Electrodeposition for Improved Frictional Properties

Alloy electrodeposition of Ni-Co alloys is known to show an anomalous codeposition behavior, in which the concentration of cobalt in the deposited alloy is higher than the concentration of cobalt ions in the electrolyte. In this study, the cobalt content in the alloy is increased from 30 to 60 at.% through introduction of bromide ions into a sulfamate bath, while addition of chloride ions does not give any significant influences to the alloy. The bromide ions are found to promote the reduction of cobalt ions but inhibit the reduction of nickel ions. Effects of the pH are also investigated to provide possible explanation to the phenomenon observed, and the anomalous codeposition behavior becomes more obvious in a more acidic electrolyte.

mentioning

confidence: 99%

Effects of Bromide Ions in Anomalous Codeposition of Ni-Co Alloys with a Sulfamate Based Electrolyte

Jiang

Chen

Kurioka

et al. 2023

“…21 In addition, the composition and micro-structure in the deposited alloy can be easily controlled by the electrodeposition parameters, such as the current density and the use of additives. 22,23 Ni-B alloy deposition through an electroless method also suffers from a low bath life. 24 Mechanical properties of metallic materials often exhibit the sample size effect, 25,26 which the mechanical strength varies as the size of the sample reduces to the micro-scale or smaller.…”

mentioning

confidence: 99%

Electrodeposition of Ni–B Alloy Film: Effect of Current Density and Heat Treatment on Micro-Mechanical Property

Jiang¹,

Chen²,

Kurioka³

et al. 2022

Ni-B alloy films are prepared by electrodeposition with a Watt’s bath-based electrolyte. The B content decreases from 14.3 at.% to 2.8 at.% as the current density increases from 1 A/dm2 to 4 A/dm2. For applications in miniaturized electronics, the micro-scale mechanical property is evaluated by micro-compression test using micro-pillar type specimens. As-deposited Ni-B alloy films exhibit high mechanical strengths and ductility. The Ni-B alloy films are heat treated to evaluate the thermal stability. After the heat treatment, strengthening and formation of an intermetallic compound, Ni3B, are confirmed. The deformation behavior of the micro-pillars changes from ductile to brittle after the 250 °C heat treatment, and the compressive strength of the Ni-B alloy film having the B content of 2.8 at.% reaches 5.67 GPa due to the precipitation strengthening mechanism by the Ni3B.

“…In these reports, the carbon black or cobalt oxide was used as a solid lubricant to reduce the coefficient of friction and the amount of wear. Carbon nanotubes (CNTs) also function as a solid lubricant, 18 and the lubricities of Ni-P alloy/CNT, [19][20][21][22][23] Cu/CNT, 24 Ni/CNT, 25,26 Co/CNT, 27 and Co-W alloy/CNT 28 composite films prepared by electroplating or electroless plating have been investigated. In the case of Ag/CNT composite plating, excellent electrical contact characteristics of the Ag/CNT composite film prepared using a cyanide bath have been reported.…”

mentioning

confidence: 99%

Electrodeposition of Ag/CNT Composite Films from Iodide Plating Baths

Arai

Kikuhara

Horita

2020

Self Cite

Ag/carbon nanotube (CNT) composite films were prepared by electrodeposition from non-cyanide baths. An iodide bath and multiwalled CNTs were used. The stability of the iodide bath under ambient conditions at various pH levels was examined, along with the changes in visual appearance, pH, and triiodide ion (I3 −) concentration. The electrodeposition was conducted under galvanostatic conditions using iodide baths with and without CNTs. The microstructure of the Ag and Ag/CNT composite films was characterized, and the hardness, electrical conductivity, and coefficient of friction of the films were measured. The iodide bath was stable at higher pH levels under ambient conditions. The obtained Ag/CNT composite films exhibited a compact structure, and CNTs were homogeneously distributed in the interior of the deposited Ag matrix. The CNT content in the deposits increased with increasing CNT concentration in the plating bath. The hardness of the Ag/1.2 mass%-CNT composite film was 63.2 HV, which was slightly greater than that of the Ag film (60.4 HV). The resistivity of the composite film was 1.9 μΩ cm, which was slightly higher than that of the pure Ag film (1.8 μΩ cm). The coefficient of friction of the composite film was lower than that of the Ag film.