(150h) Reduction of Prticle Jamming in Abrasive Slurries

Abrasive particle slurries are important in many applications, including jet cutting, but their use for this purpose is limited by particle settling and jamming. A number of gel-forming additives have been found to prevent particle sedimentation, but particle jamming in flow constrictions remains a problem. This work investigates the effectiveness of surfactant boundary lubricants to increase lubricity and relieve jamming in model aqueous slurries of 50-μm diameter garnet abrasive particles. Lateral force microscopy (LFM) is used to characterize the lubricity of garnet surfaces pre-treated with cationic and neutral surfactants or functionalized with an octadecylsilane. All three treatments are found to produce significant increases in lubricity, which are found to correlate with the results of macroscopic jamming tests. In these tests, garnet particle slurries are made to flow through the constriction provided by a syringe. Reductions of approximately 50% in jamming were achieved even under high particle loading conditions using the silane surface functionalization.