Preparation And Tribological Properties Of Silver / Palygorskite Composite Nano - Grease Additive

Friction wear is the main reason causing mechanical components failure and energy consumption. The loss of our country caused by friction wear is as high as 950 billion, and the application of tribology knowledge and research can save at least 327 billion. Therefore, the research and development of new efficient lubricants has become a major research field of tribology.Grease has been widely used in the industrial fields because of its unique rheological properties.This article will take compound hard nan- palygorskite and soft nano-silver as grease additives, study on the preparation method of silver/ palygorskite and its dispersion in the grease, evaluate the extreme pressure and antiwear properties of lubricating grease by using four-ball friction wear tester,and study anti-wear mechanism of grease additive by grinding marks of ball milling spot for SEM, EDS detection.The main research content and conclusions of this topic include:(1) Preparation of silver/palygorskite Nano-composite Particles. This paper uses silane coupling agent Kh550 as surface modifier, designes different ways to prepare silver/palygorskite nano-composite particles and does TEM and FTIR detection for them. FTIR test results show the silver/palygorskite nano-composite particles are all successfully modified. TEM test results show the particle size of silver/palygorskite nano-composite particles with mechanical ball milling and chemical coating method is minimum and the reunion between the particles is not serious comparing with other preparation methods. The silver/palygorskite nano-composite particles with this preparation method is nano scale, meets the requirements of grease additives.(2) Researching on the dispersion technism of silver/palygorskite nano-composite particles in the grease. As grease additives, the dispersion state in the grease of silver/palygorskite nano-composite particles directly affect grease tribological properties. In order to determine the dispersion method of additives in the grease, different dispersion technism are desigmed in the laboratory. By comparison of dispersion processes, phenomena,the advantages and disadvantages, the friction and wear test are done on a variety of grease. The tribology results showe that the grease prepared by dilution-ultrasonic dispersion method exhibite good friction-reduction and antiwear properties.(3) Studying on optimum ratio of each components of silver/palygorskite ano-composite particle and optimal proportion in grease. With the characteristics of different friction-reduction and antiwear properties of silver/palygorskite nano-composite particle, different ratio of each components and different proportion in grease will all affect the tribological properties of grease.Therefore, a series of grease are prepared in the laboratory and the friction-reduction and antiwear properties of silver/palygorskite nano-composite particles are detected by friction and wear tester. The results of comprehensive evaluation method show:when the value of composite particles of silver/Palygorskite is 1:1, the proportion of silver/palygorskite nano-composite particles in the grease is 2.5%, both the cooperativity and tribological properties of silver/palygorskite nano-composite particles are best,and the grease has the best anti-friction abrasion resistance.(4) The antiwear and friction reducing mechanism of the silver/palygorskite nano-composite particles is discussed. The SEM and EDS are used to test the wear spot on the surface of the steel ball. The testing result is combined with the Friction and wear test result to discuss the antiwear and friction reducing mechanism of the silver/palygorskite nano-composite particles grease additive. The reason why the silver/palygorskite nano-composite particles are of good anti-wear and friction reduction properties is because the silver/palygorskite nano-composite particles can play a role of micro ball between the friction surface of the steel ball. The particles can turn the sliding friction into rolling friction. So they play a role of reducing friction. The silver/palygorskite nano-composite particles deposit on the surface of the steel ball forming selfreparing thin film to improve the wear of the surface of the steel ball. So they play a role of antiwear.Results of this study provides a theoretical basis for the application and research of composite nanomaterials,and has reference value for the study of related fields. So it has very important theoretical significance and practical value.