Synergetic effect of surface connectivity and functional parameters on the friction characteristics of a sliding contact interface

Abstract

The characteristics of surface morphology markedly affect the tribological properties of contact interface such as lubrication and seal performance. In present work, the synergetic effect of surface connectivity and some three-dimensional topography parameters (ISO 25178) on the friction characteristics of a sliding contact interface, based on mathematical morphology and reciprocating linear tribotesting, is explored. The results indicate that the friction properties of sliding contact interface was significantly affected by the variation of surface connectivity. The increase in connectivity index would improve the relative contact area on the isotropic surfaces and affect the distribution and storage characteristics of the fluid, while this enhancement would be blocked on the anisotropic surface and the variation of connectivity index is obviously nonlinear with a shocking feature. The friction tests confirm that the friction coefficient of sliding contact interface decreases with the increasing surface connectivity index, which is mainly related to the enhancement of lubricant storage and flow in each void region and improving the lubrication behavior. Furthermore, the same variation law is applicable to the relationship between the functional morphology parameters and the friction property. The increasing Vvv and Sku, would contribute to a lower friction coefficient at the interface. Our work provides deep insights into regulating the tribological property of contact interfaces through surface topography control.

Delayed Leidenfrost Effect of a Cutting Droplet on a Microgrooved Tool Surface

“…Line-by-line laser scanning is used to ablate the sample to create a microgrooved surface with varying levels of roughness (scanning speed ∼10 mm/s, frequency ∼300 kHz, the distance between adjacent grooves ∼80 m). Laser processing technology has the advantages of high machinable accuracy, good repeatability, and high processing efficiency; − the microgroove height of each sample is changed by controlling the processing power and the number of scans, and the three-dimensional topography results (Figure b) show that the prepared samples have great processing quality with uniform microgroove height. It should be noted that we formally control the depth of the microgrooves to obtain various roughness surfaces, which are labeled as follows: sample I ( Sa ∼ 0.01 μm, original smooth surface), sample II ( Sa ∼ 3 μm), sample III ( Sa ∼ 6 μm), sample IV ( Sa ∼ 9 μm), and sample V ( Sa ∼ 12 μm).…”