【摘 要】
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In this study,the phase transformation and micromorphology evolution of sepiolite nanofibers were studied along with the increase of temperature from 300 to 1300oC,using natural sepiolite samples as r
【机 构】
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Key Laboratory of Special Functional Materials for Ecological Environment and Information(Hebei Univ
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In this study,the phase transformation and micromorphology evolution of sepiolite nanofibers were studied along with the increase of temperature from 300 to 1300oC,using natural sepiolite samples as raw materials.Through characterization by scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),thermo-gravimetric analysis(TG/DTG)and differential scanning calorimeter(DSC),it was found that the determined transition temperature values for the dehydrations of the hygroscopic water and the zeolitic water were 120 oC and 340oC,and the values for the dehydration of the bound water and the dehydroxylation of the hydroxyls were about 500oC and 810oC.Moreover,orthoenstatite(MgSiO3)was recrystallized from dehydroxylated phase at 852oC and then transformed into protoenstatite at 970oC,and enstatite crystals grew along with c-axis of the fiber with the increase of temperature.Amorphous phase as the other phase of sepiolite dehydroxylation recrystallized into cristobalite in the temperature range of 1130~1200oC,and the samples began to melt at the above temperature range.In terms of morphology,both sepiolite bundles and laths remained constant after heating up to 1000oC and sintering phenomenon appeared when the temperature was up to 1100oC.The bundles partly melted and adhered each other,which further formed a porous structure after calcination at 1200oC.When the temperature was up to 1300oC,the sample substantially melted except for a small amount of entatite and cristobalite crystals.The present study reflects the thermal reaction of sepiolite,which could be applied in exploring the reinforcement mechanism in sepiolite reinforced ceramic body composites.
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