Dynamic and wear study of an extremely bidisperse magnetorheological fluid

摘要: In this work the friction and wear properties of five magnetorheological fluids (MRFs) with varying compositions are investigated. Considering that many proposed applications for these involve lubricated contact between mobile metal–metal or polymer–metal parts, relationship MR response behavior appears to be fundamental importance. One (MR#1) contains only iron microparticles base oil; second third ones (MR#2 MR#3) contain an anti-wear additive as well. The fourth one (MR#4) is a well known commercial MRF. Finally, MR#5 stabilized by dispersing particles in magnetite ferrofluid. latter fluid better (higher yield stress post-yield viscosity) than others. More importantly, it remains (and even improves) after test: pressure applied four-ball apparatus produces compaction layer around microparticles. Additionally, coefficient larger, which seems paradoxical principle, but can explained considering stability comparison other four MRs, appear undergo partial phase separation during test. fact, electron optical microscope observations confirm milder effect MR#5, almost complete absence scars from steel test spheres homogeneous shallow grooves on them. Comparatively, MR#2, MR#3 and, particularly, MR#1 produce much more significant wear.