Direct Correlations among the Grain Size, Texture, and Indentation Behavior of Nanocrystalline Nickel Coatings

Abstract

By using nc-Ni coatings as a model system, systematic experiments were designed to evaluate the interaction between the microstructural and mechanical properties tailored by electrodeposition conditions. A direct correlation between grain size and texture was established for the first time. The grain size of the (111) crystalline plane decreases with the texture coefficient (RTC) regardless of the process conditions, and that of the (220) plane has different trends. Then, a peculiar phenomenon is revealed that the dependence of hardness on grain size is accurately described by the Hall-Petch relationship when changing the temperature or pH, but with different slopes, while it deviates from such a relationship with changing current density, denoting more underlying mechanisms related to texture. Finally, a surprising degree of influence of texture on hardness and elastic modulus is also presented, with the overall trend of hardness increasing with texture; and when the RTC of (111) exceeds 40%, the elastic modulus increases with texture, implying a fundamental relationship between modulus and texture. Texture predominates over the other factors on the elastic modulus, revealing the importance of elastic anisotropy. Significantly, the present work suggests a useful tailoring routine to fabricate high quality nc-Ni coatings with the desired structure and mechanical properties.

Improved Hardness and Thermal Stability of Nanocrystalline Nickel Electrodeposited with the Addition of Cysteine

“…The enhancement of the hardness due to the addition of 0.1–0.2 g/L cysteine can be attributed to the reduced grain size, the increased defect density and the development of (111) texture. Indeed, former studies have shown that (111) texture yielded a higher hardness than that for other crystallographic directions in fcc metals [ 68 , 69 ]. Although the defect density increased when the cysteine content was raised from 0.2 to 0.3 g/L, further enhancement in the hardness was not observed.…”

A new approach to evaluate the elastic modulus of metallic foils

“…The values of M corresponding to the different foils are summarized in Table 1. This method was first described [46] and has been used by others to describe thin film materials [47,48], coatings [49] as well as ED copper [44,[50][51][52]. Differences in terms of orientation can also be seen by XRD scans presented in Fig.…”

Effect of hBN on Corrosion and Wear Performances of DC Electrodeposited NiW and NiW–SiC on Brass Substrates

“…A rapid rise in anodic current density at the potential below the potential of oxygen evolution can be due to: (1) Local dissolution of passive films and formation of metastable pits in the presence of aggressive Cl − ions; (2) presence and propagation of active defects on the surface of passive layer. The potential at which current density increases sharply is called critical pitting potential, pitting potential, rupture potential, or breakdown potential [44][45][46]. In order to investigate the materials' response to the pitting corrosion, the scanning direction of the potential was changed at the pitting potential from positive values toward the negative values.…”