The Tribological Properties Of Layered Silicates And Their Modified Materials

Layered materials are one kind of important functional materials, which have a wide range of applications in some significant industries such as energy and chemical industry. Layered sodium silicate, belongs to the group of layered materials, possess the properties of ion exchange and adsorption and it can be used as environmentally friendly non-phosphorous detergent builder because of its strong cation exchange capacity. Exploring new characteristic and application of the materials is always the direction of development of material research. Then, according to the characteristic of layered crystal structure, the application possibility of layered silicates and their modified materials was expected to expand into the field of lubricant additive in this paper.The tribological properties of organic pillared layered sodium silicate, compound system of layered sodium silicate and surfactant and layered calcium silicate CAS-1 were analyzed, the effects of lubricant additives on improving the load-carrying capacity, friction-reducing and anti-wear properties of base oil were investigated in this paper. Typical samples were tested and characterized by four-ball tester, optical microscope, XRD and SEM observation.Firstly the tribological properties of organic pillared layered sodium silicate were analyzed in this paper, the result showed that: The 100SN base oil had the best tribological properties when the ratio of bisoctyl dimethyl ammonium chloride pillaredδlayered sodium silicate was 0.5wt%. Compared with the 100SN base oil, PB value was increased by 8.5%, wear scar diameter was decreased by 33.3% and friction coefficient was decreased 24.1%. The 100SN base oil had the best tribological properties when the ratio of N,N-dimethyl-N,N-dioctadecyl ammonium chloride pillaredδlayered sodium silicate was 1.0wt%. Compared with the 100SN base oil, PB value was increased by 8.5%, wear scar diameter was decreased by 19.8% and friction coefficient was decreased 22.8%. Lubrication tests indicated that as the additive organic pillared layered sodium silicate could improve the load-carrying capacity, friction-reducing and anti-wear properties of 100SN base oil, and they were proved to keep the layered structure by XRD analysis during the test.Secondly the tribological properties of compound of layered sodium silicate and surfactant were analyzed, the result showed that: The 100SN base oil had the best tribological properties when the ratios of compounds ofδlayered sodium silicate and dodecylbenzene sulfonic acid, dinonylnaphthalene- sulfonic acid, sodium dodecyl sulfate were all 1.0wt%.Compared with the 100SN base oil, PB values were increased by 27.2%, 8.5% and 16.8%;wear scar diameters were decreased by 26.7%,20.8% and 28.6% and friction coefficients were decreased by 29.7%,16.6% and 25.5%, respectively. The 100SN base oil had the best tribological properties when the ratios of compounds ofβlayered sodium silicate and dodecylbenzene sulfonic acid, Dinonylnaphthalenesulfonic acid were both 1.0wt%.Compared with the 100SN base oil, PB values were increased by 37.7% and 27.2%;wear scar diameters were decreased by 17.3% and 10.2% and friction coefficients were decreased by 25.5% and 19.3%, respectively.The 100SN base oil had the best tribological properties when the ratio of compound ofβlayered sodium silicate and sodium dodecyl sulfate was 0.5wt%. Compared with the 100SN base oil, PB value was increased by 16.8%, wear scar diameter was decreased by 21.1% and friction coefficient was decreased 22.8%.Lubrication tests indicated that as the additives compounds of layered sodium silicate and surfactant could improve the load-carrying capacity, friction-reducing and anti-wear properties of 100SN base oil, and layered sodium silicates were proved to keep the layered structure stable by XRD analysis during the test.Then the tribological properties of layered calcium silicate CAS-1 were analyzed in this paper, the result showed that: The 100SN base oil had the best tribological properties when the ratio of layered calcium silicate CAS-1 was 0.5wt%. Compared with the 100SN base oil, PB value was increased by 16.8%, wear scar diameter was decreased by 40.0% and friction coefficient was decreased 23.4%. Lubrication tests indicated that as the additive layered calcium silicate CAS-1 could improve the load-carrying capacity, friction-reducing and anti-wear properties of 100SN base oil, and it was proved to keep the layered structure by XRD analysis during the test.