Study on Friction and Lubrication Characteristics of Surface with Unidirectional Convergence Texture

Abstract

In order to study the influence of texture on the wear and lubrication performance of the surface of the tools, three kinds of textures with unidirectional convergence morphology were processed on the surface of the samples, and each texture was designed with different area occupancy ratios. Simulation analysis shows that, owing to the reflow and convection effect of liquid in the texture, the lubricating film flowing through the textured surface has a high hydrodynamic pressure value, and the semicircular ring texture is the most prominent. By comparing the friction coefficient, when the area occupancy ratio of texture on the surface is 10%, the surface of the samples with different morphology has the lowest coefficient of friction; the friction coefficient of the semicircular ring textured surface is especially very low. Surface textures reduce the direct contact area between the friction pairs, and generate dynamic pressure lubrication and secondary lubrication, so that the surface friction coefficient of the samples is obviously reduced. The surfaces of the non-textured samples have abrasive wear and contact fatigue wear, and the surfaces of the textured samples have adhesive wear, abrasive wear, and cavitation.Coatings 2019, 9, 780 2 of 21 chemical properties of the surface can be improved by changing the surface morphology, such as surface texture. In 1966, Hamilton [8] proposed the additional fluid dynamic pressure effect; that is, when the liquid flows through the pits or grooves machined on the surface of the friction pair, a small convergence wedge and a divergent wedge are formed. When the friction pair is in relative motion, the fluid in the convergence wedge generates a dynamic pressure effect, thereby forming a positive pressure; while in the divergent wedge, owing to the existence of the "cavitation" phenomenon, the "negative pressure" of the fluid is restrained. Therefore, additional hydrodynamic pressure is formed between the friction pairs, which improves the bearing capacity of the fluid.Liu et al.[9] used a picosecond laser to achieve micro-texture on the surface of cast iron, and investigated the friction and wear properties of four different surfaces of smooth, pit textures, net textures, and intermittent textures. The study found that under the dry friction condition, the surface machined micro-texture can significantly improve the stability of the friction coefficient compared with a smooth surface, but different textures have different effects on the stability and initial value of the friction coefficient.Gachot et al.[10] fabricated regular pits on the silicon surface by photolithography and wet etching, and tested the friction under boundary lubrication. The results show that the high-density pit morphology has a low coefficient of friction, and when the sliding direction and pit row of the cloth is at a 30 degree angle, the friction is reduced. Zeeshan Ur Rehman [11], Faiz Muhaffel [12], and Aliofkhazraei [13] have also done a lot of research in the field of coatings and textures. E...

Tribological Behavior of Bioinspired Surfaces

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Friction and wear performances of 7075 aluminum alloy surface with V-shaped microtexture via numerical simulation and experimental characterizations

“…It was found that the lubricant film thickness formed on the V-shaped microtextures was greater than those of the circular and grooved surfaces. Li et al (2019) investigated the effects of V-shaped, circular and triangular microtextures on the friction properties of cemented carbide surfaces through numerical simulations and friction wear tests. The results showed that the V-shaped microtextures had the lowest friction coefficient.…”

Effect of laser texturing bulges on tribological properties of 316L stainless steel

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