Nanomechanical, Tribological, and Scratch Properties of Electroless Ni-B-W Alloy and Ni-B-W-SiC Composite Coatings

Abstract

Electroless deposition process can develop composite coatings superior in mechanical and tribological characteristics. The deposited alloy matrix with the reinforcement of a hard ceramic phase can produce a stronger composite coating, favorable for industrial applications. Fabrication process of Ni-B-W-SiC electroless composite coating on steel substrate by reinforcing silicon carbide (SiC) in ternary Ni-B-W matrix is presented in this report. Characteristics of the developed composite coating are studied in reference to electroless ternary Ni-B-W alloy coating. These ternary alloy and composite coatings are also subjected to heat treatment (450oC, 1 hr) to observe the changes. All coated samples are characterized with FESEM, XRD, ICP-AES, and HRTEM analyses to draw conclusions in comparative studies concerning morphological features, compositions, and phase structures. Cross-sectional and Raman spectroscopic examinations are performed to authenticate the presence of SiC phases in alloy matrix. To get a further insight on the nature, various nanomechanical and tribological properties of these coatings are evaluated and subsequently co-related. Coatings developed with silicon carbide particles present in matrices show remarkable improvements in nano-hardness (H), reduced modulus (Er), yield strength, and fraction of plastic work done. Heat treatment imparts propitious effects on these mechanical properties due to the formation of harder nickel boride (Ni3B, and Ni2B) phases. Heat-treated Ni-B-W-SiC composite subjected to tribological and micro-scratch testing reveals a significant improvement in sliding wear and scratch resistance as compared to those in other coatings.

Development of Ni-B electroless coating from stabilizer free bath and characterization of high temperature tribological behaviour, scratch and corrosion resistance

“…The coatings are severely deformed at the end of scratch test (figures 21(c), (f) and (i)). The scratch hardness of the stabilizer free coatings is also lower compared to ENB-W variants [45][46][47]. The coating adhesion for stabilizer free bath results in coating delamination at high temperature.…”

Deposition and process parameter optimization of electroless Ni-B coating from a stabilizer free bath to achieve enhanced microhardness, scratch-hardness and adhesion using taguchi’s methodology

“…The microhardness increases from 704.78 to S5) shows a 3.49% S/N ratio improvement in microhardness and 3.53% S/N ratio improvement in scratch-hardness. The optimal scratchhardness is also significantly high and comparable to that of Ni-B-W and Ni-B-W-SiC coatings derived from a bath with lead stabilization and is considered to be superior in terms of tribological behaviour compared to the binary ENB alloy [8]. A comparison of the hardness values obtained by other researchers is shown in table 2.…”

“…With this deposition method, the uniform layer thickness can be achieved regardless of the shape of the substrate to be applied [6]. The primary function of coatings is to protect the surfaces of components from phenomena such as wear and corrosion and even to increase hardness and scratch-hardness [7,8]. Its excellent mechanical, chemical, and thermal properties make them ideal for automotive, electronics, oil and gas, aerospace, plastics, optics, and printing.…”

Evaluation of adhesion strength and tribological characteristics of Ni-Co-BN nano-coating developed by magnetron sputtering

“…The tribological properties of solid lubricating coatings such as dichalcogenides of transition metals (sulphides, tellurides of tungsten, and niobium etc) is primarily used to overcome friction where liquid lubricating oils are not feasible or are ineffective. unable to prevent metal contact [11][12][13][14][15][16]. These solid lubricants, like boron nitride (BN), are made up of layers of various materials called lamellae which refer to a plate-like structure that occurs in multiples in a variety of contexts, such as bio and material sciences.…”