Synchrotron radiation X⁃ray diffraction analysis of pyrophyllite under high⁃pressure
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Graphical Abstract
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Abstract
High⁃pressuresynchrotronradiationX⁃raydiffractionexperimentonpyrophyllitepowdersof MentougouinBejingwerecarriedout*Itwasfoundthatthe(002)peakofpyrophyllitewasdiminished whenpressureupto15GPa,thelayeredorderlystackingstructureofpyrophyllitewasdestroyed,sothe iso⁃staticpressuretransmissionpropertiesofpyrophyllitedecreasedgreatlyandtheupperlimitedpres⁃ surewasdeterminedtobe15GPa*Thecrystalfacespacingofhigh⁃pressuresynchrotronradiationX⁃ray diffractionanalysisresultsofpyrophyllitewascompressedduringthepressureuploadingprocess,andre⁃ siliencedbutalwaysinacompressedstateduringthepressureunloadingprocess*Thecompressionratio ofpyrophyllitein(002)crystalfacewasthemaximum,nextin(020)andfinallyin(200)face*Under thediamondsynthesispressureof6GPa,thecompressionratioofpyrophyllitein(002)crystalfaceis 3*76% whichisabout3timesgreaterthanthatofthe(020)and(200)faceofpyrophyllite,theratio
ofpyrophyllitein(200)crystalfaceisabout0*6%~0*7%,whichismuchhigherthanthatin(020) crystalface(0*1%~0*2%)underunloadingprocess*Thereforethesealingfunctionmainlydepended onthereboundingpropertyof(002)and(200)crystalfaceduringunloadingprocess*
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