Effect of variations in Ni-W molar ratio on the microstructure, mechanical properties and tribology of electrodeposited Ni-W/diamond composite coatings

Figures & data

Table 1. Effect of diamond reinforcement on Ni-based alloys.

Author/Paper title	Hardness (as deposited) Ni-based alloy/composite v/s Optimal hardness of Ni alloy-based diamond composite deposits) (Hv)	Hardness difference (Hv)	Wear (wear rate/abrasion loss/mass /weight loss) (as deposited) Ni/Ni-alloy/composite v/s Optimal wear (wear rate/abrasion loss/ mass/weight loss) of Ni/Ni-alloy based diamond composite deposits)	Wear difference
Hong et al./The microstructure, wear and electrochemical properties of electrodeposited Ni-diamond composite coatings: Effect of diamond concentration	229 Hv/613 Hv	384 Hv	Wear rate: ≈13.425 × 10^−5 mm^3/Nm / 1.79 × 10^−5 mm^3/Nm	11.635 × 10^−5 mm^3/Nm
Qu et al./Diamond particles-reinforced Ni-based composite coating on Ti6Al4V alloy: Microstructure, mechanical, dynamic impact and dry-sliding tribological properties	30.85 GPa/37.92 GPa	7.07 GPa	Wear rate: 46.74 × 10^−5 mm^3/Nm/ 7.79 × 10^−5 mm^3/Nm	38.95 × 10^−5 mm^3/Nm
Liu et al./The icrostructures and properties of diamond reinforced Cu–Ni–Si–Ti alloys	226.8 Hv/291.4 Hv	64.6 Hv	–	–
Liu et al./Relationship between annealing time and the mechanical, tribological and corrosion properties of Ni–Mo/diamond coatings	5.9 GPa/9.3 GPa	3.4 GPa	Wear rate: 13.6 × 10^−6 mm^3 N^−1 m^−1/ 2.1 × 10^−6 mm^3 N^−1 m^−1	11.5 × 10^−6 mm^3 N^−1 m^−1
Si et al./Adding Hf element to improve the strength and wear resistance of diamond brazed with Ni-based boron-free brazing filler metal	≈273 Hv/≈2293 Hv	≈20 Hv	Wear abrasion loss: ≈25 mg/≈16 mg	≈9 mg
Xiao et al./Electrodeposition, microstructure and tribological performance of Ni/(N) incorporated diamond-like carbon films	≈390 Hv/461.50 Hv	≈71.50 Hv	Wear mass loss: ≈8 × 10^−5 kg m^−1/ 3.33  × 10^−5 kgm^−1	≈4.67× 10^−5 kg m^−1
Zhang et al./Enhancement of the wear resistance of Ni-diamond composite coatings via glycine modification	350 Hv/580 Hv	330 Hv	Wear rate:  35 × 10^−5 mm^3/ Nm to 17 × 10^−5 mm^3/Nm	18× 10^−5 mm^3/Nm
Liu et al./Influence of particle size and content on the friction and wear behaviors of as-annealed Ni–Mo/diamond composite coatings	≈9 GPa/15.4 GPa	6.4 GPa	Wear rate: 6.7 × 10^−6 mm^3 N^−1 m^−1/ 2 × 10^−6 mm^3 N^−1 m^−1	4.7 × 10^−6 mm^3 N^−1 m^−1
Zhang et al./Preparation and hardness of pulse electrodeposited Ni–W–diamond composite coatings	≈620 Hv/≈980 Hv	≈360 Hv	–	–
Wang et al./The effect of heat treatment on the microstructure and mechanical properties of electrodeposited nanocrystalline Ni–W/diamond composite coatings	≈725 Hv/1205 Hv	≈480 Hv	Wear weight loss: ≈2.75 mg/0.1 mg	≈2.65 mg
Preparation and wear resistance of lectrodeposited Ni–W/diamond composite coatings	734 Hv/818 Hv	84 Hv	Wear weight loss: ≈1.7 mg/≈1.1 mg	≈0.6 mg

Figure 1. Schematic representation of the diamond co-deposition on the base Ni-W alloy matrix.

Table 2. Plating bath constituents and electrodeposition parameters.

Plating bath composition		Electrodeposition parameters
NiSO4.6H2O	23.5 g/L (for Ni:W molar ratio = 0.22), 37.4 g/L (for Ni:W molar ratio = 0.35) 44.85 g/L (for Ni:W molar ratio = 0.42), 53.4 g/L (for Ni:W molar ratio = 0.5), 80.1 g/L (for Ni:W molar ratio = 0.75), 106.8 g/L (for Ni:W molar ratio = 1), 213.6 g/L (for Ni:W molar ratio = 2)	Temperature	75 °C
Na2WO4.2H2O	53 g/L	Current density	0.15 A/cm^2
Na3C6H5O7	168 g/L	RPM	200
NH4Cl	31 g/L	pH	8.9
NaBr	18 g/L	Ni:W molar ratio	0.22–2
Diamond	10 g/L	Deposition time	2 h

Figure 2. SEM Image for different Ni:W ratio in Ni-W/diamond composite coatings fabricated at 75 °C, 0.15 A/cm² current density,10 g/L diamond concentration and 8.9 pH (a) 0.22 (b) 0.35 (c) 0.42 (d) 0.75 (e) 1 (f) 2.

Figure 3. Cross-sectional SEM Image for different Ni:W ratio in Ni-W/diamond composite coatings fabricated at 75 °C, 0.15 A/cm² current density,10 g/L diamond concentration and 8.9 pH (a) 0.22 (b) 0.35 (c) 0.42 (d) 0.75 (e) 1 (f) 2.

Table 3. Ni and W content in the Ni-W base matrix of the NWD coatings as per the EDS results.

Ni:W molar ratio	Amount of NiSO4.6H2O in the plating bath (g/L)	Ni content (in the NWD coatings) (at.%)	Amount of Na2WO4.2H2O in the plating bath (g/L)	W content (in the NWD coatings) (at.%)
0.22	23.5	80.98	53	19.02
0.35	37.4	80.07	53	19.93
0.42	44.85	81.70	53	18.3
0.5	53.4	83.82	53	16.18
0.75	80.1	90.23	53	9.77
1	106.8	94.96	53	5.04
2	213.6	97.90	53	2.1

Figure 4. Deposition rate for different Ni:W ratio in Ni-W/diamond composite coatings fabricated at 75 °C, 0.15 A/cm² current density,10 g/L diamond concentration and 8.9 pH.

Figure 5. XRD Patterns for different Ni:W ratio in Ni-W/diamond composite coatings fabricated at 75 °C, 0.15 A/cm² current density,10 g/L diamond concentration and 8.9 pH.

Figure 6. High resolution (5000x) SEM image for different Ni:W ratio in Ni-W/diamond composite coatings fabricated at 75 °C, 0.15 A/cm² current density,10 g/L diamond concentration and 8.9 pH (a) 0.22 (b) 0.35 (c) 0.42 (d) 0.75 (e) 1 (f) 2.

Figure 7. Hardness values for different Ni:W ratio in Ni-W/diamond composite coatings fabricated at 75 °C, 0.15 A/cm² current density,10 g/L diamond concentration and 8.9 pH.

Figure 8. W content for different Ni:W ratio in Ni-W/diamond composite coatings fabricated at 75 °C, 0.15 A/cm² current density,10 g/L diamond concentration and 8.9 pH.

Figure 9. Grain size comparison for different Ni:W ratio in Ni-W/diamond composite coatings fabricated at 75 °C, 0.15 A/cm² current density,10 g/L diamond concentration and 8.9 pH.

Figure 10. EDS element mapping Graph for the Ni-W base matrix for the Ni-W/diamond composite coatings fabricated at various Ni-W molar ratios (a) 0.22 (b) 0.35 (c) 0.5 (d) 0.75 (e) 1 (f) 2.

Table 4. Effect of the variation of Ni-W molar ratio on the hardness of Ni-W alloy and Ni-W/diamond composite coatings.

Ni:W molar ratio	Hardness (Ni-W alloy) Hv	Hardness (Ni-W/diamond) Hv
0.22	708 ± 18	767 ± 12
0.35	737 ± 13	1195 ± 19
0.426	755 ± 11	1207 ± 16
0.5	771 ± 9	1081 ± 21
0.75	797 ± 16	1346 ± 9
1	706 ± 12	1093 ± 14
2	702 ± 17	1164 ± 16

Figure 11. Effect of the variation in Ni-W molar ratio on the surface roughness of Ni-W/diamond composite coatings fabricated at 75 °C, 0.15 A/cm² current density,10 g/L diamond concentration and 8.9 pH.

Figure 12. Effect of the variation in Ni-W molar ratio on the friction co-efficient of Ni-W/diamond composite coatings fabricated at 75 °C, 0.15 A/cm² current density,10 g/L diamond concentration and 8.9 pH.

Figure 13. Effect of the variation in Ni-W molar ratio on the wear rate of Ni-W/diamond composite coatings fabricated at 75 °C, 0.15 A/cm² current density,10 g/L diamond concentration and 8.9 pH.