Effect of Nanodiamond Concentration and the Current Density of the Electrolyte on the Texture and Mechanical Properties of Ni/Nanodiamond Composite Coatings Produced by Electrodeposition.

Meihua Liu,Yan Shi,Dongai Wang,Yunlan Gong,Linan Li,Wengang Zhang,Feihui Li,Lianjin Li,Hongnan Liu,Bing Liu

doi:10.3390/ma12071105

Abstract

An Ni/nanodiamond composite coating was deposited on carbon steel in a traditional Watt’s solution without additives via direct current (DC) electroplating. The effects of the nanodiamond concentration and current density in the plating solution on the morphology, grain size, and texture of the Ni/nanodiamond composite coating were observed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The distribution of the nanodiamond particles in the composite coating was investigated by Raman spectra and SEM. The mechanical properties of the composite coating, such as its elastic modulus and hardness, were examined using a Nano Indenter XP nanometer mechanical test system. The coefficient of friction was tested using a Universal Micro-Tribotester. The results demonstrated that the preferential orientation of the Ni/nanodiamond composite coating varied from the (111) crystal orientation of the pure nickel coating to the (200) crystal orientation. When the nanodiamond concentration in the plating solution was 8.0 g/L and the current density was 3.0 A/dm2, the hardness of the composite coating reached the maximum value of 5.302 GPa and the friction factor was maintained at around 0.1. The average grain size of the composite coating was reduced to 20.4 nm.

Highlights

IntroductionParticle-reinforced metal matrix composites have many advantages, such as a low cost, corresponding high hardness, good wear resistance and corrosion resistance compared to pure metals or alloys [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19]
It can be seen that the current is low when the potential is in the range −0.6~−0.8 V, which indicated that the substantial reduction of Ni2+ had not yet started, and the current
Comparing the over-potential of the different curves under the current, itofcan be found that concentration; the over-potential increased decreased the increase withsame the increase nanodiamond thefirst highest over-potential waswith obtained when the of nanodiamond concentration; the highest over-potential was obtained when the nanodiamond nanodiamond concentration in the plating solution was 8 g/L

Summary

Introduction

Particle-reinforced metal matrix composites have many advantages, such as a low cost, corresponding high hardness, good wear resistance and corrosion resistance compared to pure metals or alloys [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19]. Unique mechanical and tribological properties, including especially nanodiamond particles high hardness and a low friction coefficient of the ultra-fine nanodiamond powders, have attracted researchers to conduct further investigation into their utilization as coatings and as composite coatings.

Methods

Results

Conclusion