Investigation of Effects of Electroplating Conditions on TEMPO-Oxidized Cellulose Nanofiber Composited Nickel Electroplated Films

Abstract

The effects of plating conditions on nickel (Ni) electroplated films composited with 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-oxidized CNFs (CNFs) were investigated. Plating experiments were performed by varying the amount of CNFs added to the Watt's bath, the current density, and the stirring speed. The plated film obtained at 3 g/L, 2.5 A/cm2, and 300 rpm of them respectively, reached an average 483 HV of the surface hardness, which was the highest in this study. The surface hardness of the conventional Ni film without CNFs plated under the same conditions was an average of 239 HV, and the hardness improvement effect was more than twice as high. The hardness improvement effect due to dispersion enhancement tended to increase as more CNFs were more finely and densely composited into the Ni film, although different trends were observed when the current density was varied.

An Evaluation of the Wear Resistance of Electroplated Nickel Coatings Composited with 2,2,6,6-Tetramethylpiperidine 1-oxyl-Oxidized Cellulose Nanofibers

“…The detection of several mass% values on the plated film without CNF was considered to be background noise [ 2 ]. In our previous study [ 4 ], the content of cellulose showed an increasing trend with the increase in CNF in the range of 1–3 g/L; thus, the trend in this study is different from that.…”

“…Figure 6 shows the appearance of the plated films. As in previous studies [ 2 , 3 , 4 ], the plated film without CNF was matte, and the plated film with CNF was bright, while the plated film with CNF showed uneven brightness under the conditions where 2 and 3 g/L of CNF were added.…”

“…In this study, Ni–cellulose nanofiber composite electroplated films were fabricated on steel plates using a nickel electroplating solution with the addition of cellulose nanofibers. The plating process was mainly based on previous studies [ 2 , 3 , 4 ], and the range of 1–3 g/L for the addition of cellulose nanofiber was also determined based on our previous study [ 4 ]. The obtained plated films were evaluated in terms of surface morphology, quantitative analysis, surface hardness, and Ni crystallite size.…”

“…We have been developing a new functional coating, a nickel (Ni)–cellulose nanofiber composite electroplated film, with sustainable properties [ 1 , 2 , 3 , 4 ]. Dispersion enhancement and self-lubricating properties are expected to be achieved by compounding cellulose nanofibers, which are renewable resources obtained from plants, are five times stronger than steel at one-fifth of the density, and are crystalline resin [ 5 ].…”

“…As described above, Ni–cellulose nanofiber composite electroplated films have many advantages in terms of sustainability and a low environmental load. In our previous studies [ 1 , 2 , 3 , 4 ], their fabrication conditions were investigated and revealed; however, their wear resistance has not yet been evaluated. Therefore, in order to evaluate the wear resistance and clarify the abrasion mechanism, the properties of Ni–cellulose nanofiber composite films plated on steels were investigated, and ball-on-disk abrasion tests under non-lubricated (dry) conditions and an analysis of the macro- and micro-structures of abrasion scars were conducted.…”