Fine Structure And Performance Of Tourmaline

Tourmaline powder was refined to research the refinement mechanism of tourmaline fine particles,change of microstructure and variation of spontaneous polarization and far-infrared radiation properties of tourmaline,when tourmaline particle size reduced from micron to near nanometer.Taking ceric nitrate as the metal precursor,adjoining tourmaline fine particles,composites of tourmaline/CeO₂ were obtained by using sol-gel method.Catalytic oxidation of methane property of composites was tested to further prove the effect of tourmaline refinement on its properties,and provide experimental basis for practical of tourmaline fine particles.The change of tourmaline’s microstructure during refinement was researched.The microstructure of tourmaline changed from nubby and stumpy to schistose rapidly;and then,the particles shape transformed from schistose to spheroidal gradually.During the refinement,loading frequency of stress influenced on particle size.The more loading frequency of stress,the smaller tourmaline particle sizes were.Stress value had an obvious effect on refining rate of tourmaline particles.The larger stress value was,the faster particle size decreased.Stress direction had effect on microstructure of tourmaline.When tourmaline loaded normal stress,the surface of particles was irregularity,and the edges were obtunded through long time action of stress.When tourmaline loaded share stress,the surface of particles was smooth,and the edges were in order and straight.Refinement mechanism of tourmaline particles during the refinement was studied.The refining process of tourmaline particles mainly presented transgranular fracture and exfoliation of particles under stress.The crack-tip stress fields of main crack induced the lateral crack.Meanwhile,some micro crack produced at inherent defects of particles because of stress concentration.These micro cracks largen through extending and connecting,and then continue extended under the effect of stress.The change of spontaneous polarization properties and far-infrared radiation performance of tourmaline fine particles were studied.Experimental results revealed that,the finer of the tourmaline particles,the stronger of the spontaneous polarization properties and far-infrared radiation performance.When methane catalytic oxidation composite catalysts were obtained by using sol-gel method,to join tourmaline fine particles with 2%mass fraction could promote nucleation of CeO2,inhibit the grain growth and particle agglomeration,and increase methane catalytic activities significantly.