Superlubricity Behavior with Phosphoric Acid–Water Network Induced by Rubbing

• DOI: 10.1021/la201535x
• Publication Date: 2011-06-20T10:46:07Z
• Authors: Jinjin Li; Chenhui Zhang; Jianbin Luo
• Keywords: Rubbing; Phosphoric acid; Shearing (physics)

In present work, a superlubricity phenomenon of phosphoric acid (H3PO4) was found under ambient conditions. An ultralow friction coefficient about 0.004 between glass/Si3N4 and sapphire/sapphire tribopairs obtained the lubrication aqueous solution (pH 1.5) at high contact pressure (the maximum can reach 1.65 GPa) after running-in period 600 s. The experimental results indicate that superlow state very stable for more than 3 h. such state, solidlike films formed on two sliding surfaces, which are hydrates with hydrogen-bonded network according to Raman spectrum. mechanism is mainly attributed hydrogen bond effect forms hydrated water layer low shearing strength, dipole–dipole effects form an interfacial Coulomb repulsion force also make some contributions friction. This work may help us introduce new approach lead wide application in future technological biomedical areas.