State of Art and recent trends in bulk carbon nitrides synthesis

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1、Availableonlineatwww.sciencedirect.comMaterialsScienceandEngineeringR58(2008)195227www.elsevier.com/locate/mserStateofArtandrecenttrendsinbulkcarbonnitridessynthesisGraziellaGoglio*,DenisFoy,Ge´rardDemazeauInstitutdeChimiedelaMatie`reCondense´edeBordeauxCNRS,Universite´Bordeaux1,87av.DrA.Sch

2、weitzer,33608PESSACCedex,FranceAbstractLightelement-basedmaterialsareofrelevantinterestbecauseoftheirspecificphysico-chemicalpropertiesmainlydependentontheinvolvedstrongchemicalbonds.Amongthem,diamondandc-BNarestilltodaythemostrepresentativematerialsespeciallyconcerningsuperhardnessproperty.N

3、evertheless,sincethepredictionbyLiuandCohen(onthebasisofabinitiocalculation)oftheoreticalmaterialswithC3N4compositionexhibitinglowcompressibility,manyeffortshavebeendevotedtothesynthesisofcarbonnitrides.ThefirstpartofthisreviewdealswiththebriefdescriptionofthedifferentpredictedC3N4polymorphse

4、xhibitingeitheradensenetworkoragraphiticone.Inaddition,predictedcarbonnitrideswithdifferentstoichiometryarealsodescribed.Thesecondpartpresentstheanalysisoftheprocessingroutesdescribedintheliteratureforthesynthesisofcarbonnitridesasbulkmaterials.Ifmanyattemptshavebeendevotedtohigh-pressurepro

5、cesses(directsynthesis,directconversionfromthegraphiticform,flux-assistedconversionorsolvothermalprocesses),someexperimentsperformedinmoderateexperimentalconditionshavealsobeeninvestigatedandappearasreallypromising.Acomparisonwiththedifferentprocessesdevelopedfordiamondandc-BNisassociated.Asa

6、conclusion,adiscussionaboutthepromisingroutesrelatedtobulkcarbonnitridessynthesisisgiven.#2007ElsevierB.V.Allrightsreserved.Keywords:C3N4;Carbonnitride;Synthesis;Hardmaterials;Highpressure;SolvothermalsynthesisContents1.Introduction............................................................

7、...........1962.Descriptionofcarbonnitrides...........................................................1972.1.Aboutcarbonnitridesamongthefamilyoflightelement-basedmaterials........................1972.2.StructuraldescriptionofpredictedC3N4polymorphs