Tribological properties of liquid crystals as lubricant additives

• Published in: Wear Vol. 212; no. 2; pp. 188 - 194
• Main Authors: Bermúdez, María-Dolores, Martínez-Nicolás, Ginés, Carrión-Vilches, Francisco-José
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 10.12.1997; Amsterdam Elsevier Science; New York, NY
• Subjects: Additives; Applied sciences; Contact of materials. Friction. Wear; Exact sciences and technology; Friction, wear, lubrication; Liquid crystals; Machine components; Mechanical engineering. Machine design; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Pin-on-disk; Steel-aluminium lubricated wear; Tribological properties; Steel-aluminium lubricated wear; Additives; Tribological properties; Liquid crystals; Pin-on-disk; Lubricating oil; Pin on disk machine; Wear test; Aluminium; Steel; Experimental study; Azo compound; Azoxy compound; Lubricant additive; Benzenic compound; Friction test; Azobenzene; Tribology
• ISSN: 0043-1648; 1873-2577
• DOI: 10.1016/S0043-1648(97)00152-X

Several families of liquid crystals, 4,4′-dialkyl- and dialkoxyazobenzenes, 4,4′-dialkylazoxybenzenes and cyanoaryls, have been studied as commercial oils additives. Tribological studies have been carried out on a real time pin-on-disk machine at variable temperature and concentration. Variations in viscosity and transition temperature have no significant effect on friction values. Friction values for increasing concentration solutions of liquid crystals in base oil are very similar. A 1% weight addition of liquid crystals to two different base oils lowers friction coefficients of steel for all 14 liquid crystals studied. Wear rates of steel-steel and steel-aluminium contacts are significantly lowered by addition of liquid crystals to base oil.