| The research uses the modified palygorskite powder as the additive in lubricating oil and studies its tribological performance. The content of the thesis includes crude mineral’s characteristics, purification, chemical composition and phase, activation & interlayer ion exchange, surface modification and tribological experiments.The palygorskite has two kinds of colour, which are purplish red & light grey.The former contains palygorskite 25～35%, quartz 40～55%, feldspar less than 25% and the later contains palygorskite 25～40%, dolomite 25～40%, feldspar & quartz less than 35%.Sodium Pyrophosphate is applied to purify crude palygorskite. The results of chemical analysis and XRD show that quartz, feldspar & dolomite are decreased greatly. The average grain size is 0.191um for the red and 0.220um for the yellow in Laser Particle Analyzer. Palygorskite shows short rod-like fiber bundle, which is about 20nm in diameter and 0.5-1.5um in length in SEM photos. Adsorption & Desorption of N2 Technique is used to measure hole’s distribution and specific surface area of the red sample and the yellow sample. The results are as follow: 0.4478mL/g & 0.4813mL/g; 121.13m2/g & 121.59m2/g.HCl, NaCl & LiCl are used as activation and NiCl2 & LaCl3 are applied for interlayer modification. The optimization is 1mol/L, 85℃& 1hour.Activation Index, Settling Time in Cyclohexane & Nephelometer Method are used to evaluate the effect of surface modification with Span-60. The optimization in water is Span-60 (4%), 80℃& 40min. While the optimization in oil is Span-60: palygorskite(1:1), 80℃& 20min.The results of tribological experiments show that the red palygorskite has good anti-wear and friction-reducing performance as additive in lubricating oil. The friction coefficient, temperature of friction pair, consumed power of gear wheels, noise & rubbed surface diameter are reduced by about 68%, 23%, 9%, 8.3% & 36.29%. |
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