The effect of contact stress on the sliding wear behaviour of Zn-Ni electrodeposited coatings

Abstract

Zinc-Nickel coatings, developed in the 1980's as a replacement for zinc coatings in the automotive industry, have recently gained interest in the aerospace industry to replace cadmium coatings. Due to different material properties of Zn-Ni and Cd, there is a need to characterize Zn-Ni for tribological applications. Sliding wear tests are performed on a reciprocating pin-on-flat tribometer using a steel counterface on two Zn-Ni coatings with different microstructure and surface topography. Tests were performed under 3, 7.5 and 12 N normal loads at a relative humidity of 60 % for 2000 cycles. Increasing the normal load increased the steady state friction coefficient and wear for both coatings. The smooth and dense coating was more sensitive to the change in normal load than the rough and porous coating, as the latter experienced less wear due to the columnar structure of the coating. In contrast, the smoother and dense coating, although has less wear at low loads, has more wear at high loads due to debonding of the coating. So the coating morphology affected the extent of wear due to different wear and velocity accommodation mechanisms.

Effect of glyphosate on X-ray diffraction of copper films prepared by electrochemical deposition

“…Electrochemical deposition is one of the most extensively used approaches to prepare metals, metal oxides and metal based functional materials, 14 including coatings in the electronics industry, functional nanomaterials and the multicomposite electrode materials. [15][16][17][18][19][20] The electrochemical deposition has the advantages of utilizing simple equipments and operation, mild conditions, high controllability, requiring no separation and high stability. The morphology control can be achieved by the application of the additives during the deposition process.…”

Electrodeposited Zinc-Nickel Nanocomposite Coatings

“…The coating of pattern B was formed under the same conditions as pattern A, but Mt nanoparticles were dispersed into the electrolyte solution and incorporated into the resulting coating. Since Mt nanoparticles do not give diffraction peaks upon exfoliation, no additional peaks were observed due to its presence [2,8,52,58,66,89]. The coating with Mt incorporation was thin as compared to the alloy coating without Mt but the γ-phase alloy was still formed even in the presence of Mt, confirming the Mt did not affect the deposition of the alloy phase of interest.…”

“…Exfoliated Mt, which has a plate-like structure, increases the surface area of the material when imbedded in the coating and leads to a more tortuous mean free path of the corrosion cells upon onset [5]. This technique has previously been successful with the incorporation of montmorillonite platelets into pure nickel, nickel-molybdenum and nickel-copper coatings [2,5,8,9,52,58,66]. However, many traditional particles used in composite coatings are spherical in shape.…”

“…Zinc-nickel coatings are well known in the field of corrosion resistance as a corrosion resistant material. Corrosion protective coatings are commonly used to extend the lifetime of materials such as stainless steel from corrosion onset as a substitute for more expensive, less available materials [49][50][51][52][53]. Coating zinc onto stainless steel, known as galvanization, is an industry standard to protect against corrosion.…”

Deposition processes and properties of coatings on steel fasteners — A review

“…The differences in surface morphology of Zn-Ni coatings electrodeposited through different process parameters demonstrated different fretting and sliding wear behaviours [125,126]. In a fretting wear test, Zn-Ni coatings with rough surface, which consisted of hemispherical shape of platelet agglomerates and had higher surface roughness (R a = 2.90 μm  0.35 μm), exhibited higher wear rate from the no-slip to gross-slip conditions compared to the one with smooth surface morphology and lower surface roughness (R a =1.35 μm  0.19 μm) [125].…”