| In grinding process, it’s always difficult for the grinding fluids to enter into the contact area, which causes a worsening condition betweeen the grinding area and also problems like a rapid depletion of the wheels, a deterioration of the surface quality and the grinding burn. As a solution, we present using the molecule microcapsules of β-cyclodextrin (P-CD) and different kinds of lubricant additives (oiliness improver&extreme-pressure additive) as the fillers of phenolic resin bonded abrasive tool to realize a new type of molecule microcapsule abrasive product. The molecule microcapsules of β-cyclodextrin and lubricant additives are also called supermolecular inclusion complexes that formed by the interaction between β-CD and the lubricant additives. Microencapsulation by β-CD protects the additive in the curing process of phenolic resin and the additive will be released on the contact area to maintain its lubricity in the grinding process. This research provides a practicable scheme for the lubrication problem in the grinding process, and the main work and results of the paper are as follows:(1) The stability constant and the thermodynamic parameters of the complexation between β-CD/oleic acid were studied by a competitive inclusion method, respectively. The stability constants of the complexation between β-CD and sulfurized isobutylene (T321), and also β-CD and dialkyl pentasulfide (RC2540) were studied by a phase-solubility method, respectively. The inclusion complexes of β-CD/oleic acid, β-CD/T321and P-CD/RC2540were prepared by a co-precipitation method, respectively. The inclusion complexes of β-CD/dibutyl phosphite (T304) and β-CD/tricresyl phosphate (T306) were prepared by a trituration method, respectively. Finally, the above complexes were characterized by methods of TG, FTIR and1H NMR, etc.(2) The tribological performance of above complexes of β-CD/lubricant additives were investigated by a four-ball tester in the mixture of water and PEG-600. It was found that the complex even exhibited better tribological properties than the additives themselves in certain time and loads. The chemical states of the main elements on the worn surfaces were studied according to X-ray photoelectron spectroscopy (XPS) analyses. Then the tribochemical reaction mechanisms of β-CD, lubricant additives and the complexes under boundary lubrication were explained by the negative ion radical action mechanism (NIRAM). A mixed lubrication film was formed by the complex, in which the film formed by the additives played a major role and the film formed by the fragments of β-CD exhibited an anti-friction property. The interactions among different components lead to the better tribological performance of β-CD/lubricant additives.(3) The formulation of the molecule microcapsule abrasive tools was designed and the abrasive tools were prepared by a cold compression method. The curing process was also determined and the effects of the filling of the complexes on the mechanical properties of these abrasive tools were studied. The existing form of the complexes in the organization of the abrasive tools was detected by FTIR and SEM. The result showed that the abrasive tools could meet the mechanical application conditions when contents of the fillers were less than25%. The complexes could also withstand the curing temperature of phenolic resin and the cavity of β-CD was preserved. The complex existed in the form of granules and protected the additives well in the abrasive tools.(4) The tribological properties of the abrasive tools filled with the complexes of β-CD/oleic acid, β-CD/T321and β-CD/RC2540under different filling content, rotaing speed and applied loads were investigated by a pin-on-disc tester on a UMT-3platform. Then the self-lubricating mechanism of the abrasive tool specimens filled with the complexes was studied according to XPS analysis on the worn surface of the lower discs. The results indicated that the filling of the complexes could improve the friction and wear performance of the abrasive tools. The minimum the friction coefficient and the wear rate were obtained when the content of the filler was about15-20wt.%. The friction coefficient of the abrasive tool decreased with the increase of speed and load, while the wear rate showed a reverse trend. The lubricant additives in the complex were released, and the releasing additives worked together with the β-CD to form the lubricating layers on the steel surface, which made the abrasive tools have effects of self-lubrication, anti-wear and improving the surface quality.(5) The actual grinding properties of the abrasive tool filled with the complexes of RC2540were studied on a MM7120A surface grinder and the effects of the filling content of the complexes on the grinding ratio of the wheel and the surface quality were also studied. The grinding parameters were also determined. The result showed that the wear resistance and the surface quality of the workpiece were all enhanced. Finally, the grinding mechanism of the molecule microcapsule abrasive tools was analyzed. It was suggested that the additives were released along with the decomposition of the complexes effectively. The enhanced grinding performance of the abrasive tools was believed to stem from the formation of a self-lubricating layer between the workpiece and abrasive grains. This paper laid a theoretic foundation for the using of the new type molecule microcapsule abrasive product. |
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