Preparation , Intercalation And Study On Tribological Properties Of Ce-Mg-Al Layered Double Hydroxides

Ce-Mg-Al hydrotalcites (Ce-Mg-Al-LDHs) had been prepared in different ways and process parameters. The properties of the hydrotalcites had been studied by XRD,TEM,FT-IR and TG-DTA. The tribological properties was evaluated by four-ball and so on.Ce-Mg-Al hydrotalcite was prepared by co-precipitation method, hydrothermal method and a method involving separate nucleation and aging steps. The influence of aging temperature and aging time on the outward appearance, crystallinity and particle size of LDHs had been systematically investigated. XRD analysis showed its crystal growth selectivity in different directions. The rate of crystal growth in a direction [110] crystalline face was found to be greater than that in c direction [003] crystalline face. The optimized process parameters are crystallizing at 80℃for 4h. Sample obtained under this condition was well crystallized by the method involving separate nucleation and aging steps. It had a morphology of hexagonal sheet with diameter of about 200 nm, thickness of about 30nm.The dependence of the intercalation on such reaction conditions as pH value, time, and molar had been systematically investigated. The results show that increasing time, decreasing pH value and the molar of the organic anion would promote to the intercalation reaction . The pH value is the most important condition to control the chemical equilibrium.Dodecyl sulfate and sulfonate was intercalated into LDHs by anion exchange method at optimized process parameters. The analysis showed the crystallinity of the products is large. Organic anion and single layer hydrotalcite are connected by chemical forces, and intercalated LDHs become less hydrophilic and more dispersed. The friction performance of samples had been evaluated by four-ball friction tester,gear friction tester and so on. Experimental results show that all samples have excellent friction-reducing property. hw-4 has the most excellent friction-reducing property, of which friction coefficient reduces by 45.2% , energy consumption reduces by 9% than that of basic oil. Moreover, it is confered that intercalated LDHs’property is superior to LDHs during long time experiment. Through analysis, hydrotalcites’ good friction-reducing property is concerned with its layered structure and rare earth.