Preparation, Characterization And Properties Of Nanometer-sized Calcium Borate Powders Used As Lubricant Additives

The friction is ubiquitous in nature. Recently, studies demonstrate that the loss caused by thefriction was more than50%of the world’s primary energy. And material wear is one of thethree main reasons for materials and equipment scrap. Studies have shown thatNano-materials have excellent performance of reducing friction. Nano-particles with highsurface activity and chemical activity may make it easily deposited on the worn surface,forming a protective layer, and thus the Nano-particles insitu repair the worn surfaces in themechanical operation, further effectively reduce or prevent wear and tear.In this paper, the uniform and well-dispersed spherical calcium borate nanoparticles aslubricating oil additives have been prepared by ultrasound-assisted method for first time, andcharacterized by XRD, SEM, and TG/DTA. The XRD and TG/DTA results show that thesamples exist in amorphous state at room temperature and crystalline at750℃. The ratio ofraw materials has no effect on the crystal phase. SEM images indicate that the calcium borateparticles with diameters of50nm and200³00nm can be synthesized with and withoutultrasound-assisted method, respectively. The product oil can be obtained by dispersing2%ofadditives into lubricating oil under ultrasonication and agitation. The dispersion and stabilityof lubricants were characterized by standing observation. The performance of lubrication oilwas examined by heavy-duty vehicles and industrial gear oil test. The results show that theas-obtained nanosized calcium borate additive exhibit excellent dispersion, stability andanti-wear friction properties. In addition, the preparation process mixed the surfactant CTAB,which greatly improved the compatibility of nano-particles. The preparation of nano-calciumborate modified lubricant has good dispersion, stability, and show better antifrictionperformance.Nano-SrB₂O₄powder was prepared by solid-state reaction at room temperature for thefirst time. The highly productive method which can be operated easily confirms to theGreen-chemistry principles. The XRD patters demonstrate that the component of theas-obtained sample is SrB₂O₄after calcination at600oC. Differential thermal analysis andthermogravimetriy （DTA/TG） curves suggest the process of dehydration and crystal transitionfrom Sr[B（OH）4]2to SrB₂O₄2H₂O. SEM observation of SrB₂O₄shows that the particles areuniform and spherical with average size of80nm in diameter. Furthermore, the mechanism of reaction was discussed. The chemical reaction of the process is assumed to be acid-baseneutralization reaction. The water that was generated from the acid-base neutralizationreaction and the release of crystal water from Sr（OH）28H₂O plays essential role in thereaction system.In this paper, we also studied the preparation and properties of nano-CaB₂O₄particles.This article using borax and calcium chloride as raw material, through relatively simpleatmospheric liquid phase reaction system prepared different particle size calcium borateparticles. During the experiment, the temperature, boron：calcium ratio and other conditionsimpacted the synthesis are conducted in this paper, and the properties of nano-CaB₂O₄particles were characterized by XRD and SEM. Finally, we get conclusion that the bestconditions of synthesis CaB₂O₄is: B:Ca is2:1and the temperature is higher then80℃.