Sliding and rolling of individual micrometre sized glass particles on rough silicon surfaces

Abstract

Access to the tribological contact behaviour of individual small particles is crucial with respect to many applications in particle technology. In this paper, we present a simple nanoindentation based approach to study the rolling friction of micrometre sized spherical particles. The results are compared to sliding friction tests, which are carried out by a nanoindentation based colloid probe technique. The potential of the approach is evaluated for borosilicate glass spheres featuring nominal radii of 2?5 and 10 mm in contact with silicon surfaces. The roughness of the latter is modified by a plasma etching process. Significant differences of sliding and rolling friction with respect to roughness are observed even though the variation of root mean square roughness only ranges from 0?3 to 2?7 nm respectively.

Rolling, sliding and torsion of micron-sized silica particles: experimental, numerical and theoretical analysis

“…Any probe which resulted in identical estimates of both characterization techniques for the sphere radius was employed for further tribological testing like normal and sliding tests. A flat end diamond indenter (20 µm diameter, Hysitron Inc.) and non-glued spheres were utilized to sample rolling and torsional friction, as detailed in [24]. The misalignment of the indenter axis was below 1 • and the RMS roughness of the central part of the punch was measured to be 4± 1 nm (lateral scale of 2.5 µm), see Figure 2.…”

Effect of surface roughness on sliding friction of micron-sized glass beads

“…[5] we will only briefly summarize them here. The cyclic sliding as well as the analysis based on the various contact models, however, is described in more depth as this represents the focus of the present work and has not been shown elsewhere.…”

“…[5,6] we already reported results of an analysis of our first data set. Assuming the lateral forces show a linear relationship, see Eq.…”

“…In Refs. [5,6] we reasoned that plastic deformation of surface asperities might be responsible for this phenomenon. A quick check on this proposition by means of characterization of area wear marks generated at very low loads (<10 μN) confirmed the occurrence of plastic deformation.…”

“…In Refs. [5,6] we demonstrated the potential of a nanoindentation based colloid probe approach. This strategy allowed for the assessment of sliding, rolling and torsional friction of individual micron sized spherical particles.…”