Functionally graded nickel–tungsten coating: electrodeposition, corrosion and wear behaviour

Abstract

Nickel-tungsten functionally graded (FG) coatings were developed by pulse electrodeposition. To make a FG structure, pulse parameters were selected in eight layers with the tungsten content increasing along the thickness. The gradual increase in tungsten content to the surface will increase wear resistance and reduce the risk of cracking at the substrate. To investigate the microstructure and cross-section of Ni-W coating scanning electron microscope and to measure the chemical composition of the coating the energy dispersive spectroscopy analysis was used. Electrochemical and pin-on-disk wear tests were performed to investigate corrosion resistance and wear behaviour of the coating, respectively. Results showed that with reduction of duty cycle or increasing of frequency along this eight-layer structure, the tungsten content increased upward the surface. Results showed the superior wear resistance of the coating as compared to that of pure nickel. Moreover, the coefficient of friction decreased from 0.74 to 0.49 by an increase in the sliding distance.On a développé par dépôt électrolytique pulsé des revêtements de nickel et tungstène classés par fonction (FG). Afin de fabriquer une structure classée par fonction, on a choisi les paramètres de pulsation dans huit couches, avec la teneur en tungstène augmentant avec l'épaisseur. L'augmentation graduelle de la teneur en tungstène vers la surface va augmenter la résistance à l'usure et va réduire le risque de fissure près du substrat. On a utilisé la microscopie électronique à balayage pour examiner la microstructure et la coupe transversale du revêtement de Ni et W, et l'analyse spectroscopique à dispersif d'énergie pour mesurer sa composition chimique. On a effectué des essais électrochimiques et d'usures par pointe-surdisque afin d'examiner la résistance à la corrosion et le comportement à l'usure du revêtement, respectivement. Les résultats ont montré qu'avec la réduction du cycle ou avec l'augmentation de la fréquence tout au long de cette structure à huit couches, la teneur en tungstène augmentait vers la surface. Les résultats ont également montré la résistance supérieure à l'usure du revêtement par rapport à celle du nickel pur. De plus, le coefficient de friction diminuait de 0.74 à 0.49 avec une augmentation de la distance de glissement.

Study on functionally graded Zn–Ni–Al2O3 coatings fabricated by pulse-electrodeposition

“…There is a gradual variation in composition/ structure over the thickness [16,17]. FG coatings lead to a lower delamination and fragmentation due to the properties not changing immediately and rapidly [16,18]. Techniques including powder metallurgy, Physical vapor deposition (PVD) and Chemical vapor deposition (CVD), thermal spraying and electroplating have been used for creating FG coatings [19].…”

Electrodeposition of multilayer Ni–W and Ni–W–alumina nanocomposite coatings

“…4,5 It is possible to achieve coatings with more desirable properties using either pulse or PRCs. 6 Adjusting and controlling the pulse parameters enables us to develop coatings of the new structure and characteristics, such as functionally graded [7][8][9][10][11] and layered structures. [12][13][14][15][16] Formerly, Co-Cu 17,18 and/or Ni-Cu 19,20 coatings with layered structure were developed using the pulse technique.…”

Functionally graded materials (FGMs): A review of classifications, fabrication methods and their applications

“…In addition to the above applications, the FGMs are widely used in various industries [269,270]: industrial tools such as cutting tools, heat-resistant coatings, abrasion, corrosion, but also in other fields [271][272][273][274][275][276][277][278][279][280][281][282][283][284][285][286][287][288]. Tian et al [289] investigated the thermal and mechanical shock resistances of a newly developed Si 3 N 4 /(W,Ti)C graded ceramic tool material using the water quenching methods and intermittent cutting test, respectively.…”