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Ceramic Materials Structures and PropertiesCeramic Materials Structures1Ceramic Materials 陶瓷材料Inorganic materials 無機材料Nonmetallic materials 非金屬材料Most ceramics are compounds between metallic and nonmetallic elementsComposed of at least two elements,and often moreAtomic bonding in ceramics ranges from purely ionic to totally covalentCeramic Materials 陶瓷材料Inorgani2MaterialIonic CharacterCaF289%MgO73%NaCl67%Al2O363%SiO251%Si3N430%ZnS18%SiC12%MaterialIonic CharacterCaF289%3Electronegativity 電負度、陰電性Electronegativity 電負度、陰電性4Stable and unstable cation-anion coordination configuration-+unstable-+stable-+stableCations are ordinarily smaller than anionscation 陽離子anion 陰離子Stable and unstable cation-ani5Coordination Number 配位數23468Coordination Number 配位數Cation-Anion Radius Ration rC/rA 1 配位數12rC/rA 1 配位數127Crystal StructuresAX TypeRock Salt Structure 岩鹽結構Cesium Chloride Structure 氯化銫結構Zinc Blende(Sphalerite)Structure 閃鋅礦結構AX2 TypeFluorite Structure 螢石結構、氟石結構ABX3 TypePerovskite Structure 鈣鈦礦結構AB2X4 TypeSpinel Structure 尖晶石結構Crystal StructuresAX Type8Rock Salt Structure 岩鹽結構NaCl,MgO,MnS,LiF,FeOrNa+=0.102 nmrCl =0.181 nmrNa+/rCl=0.564Rock Salt Structure 岩鹽結構NaCl,9Cesium Chloride Structure 氯化銫結構CsClrCs+=0.170 nmrCl =0.181 nmrCs+/rCl =0.939Cesium Chloride Structure 氯化銫10Zinc Blende Structure 閃鋅礦結構ZnS,ZnTe,SiC,ZnOrZn2+=0.074 nmrO2=0.140 nmrZn+2/rO2 =0.529Zinc Blende Structure 閃鋅礦結構ZnS11Fluorite Structure 螢石結構CaF2,ZrO2,UO2,PuO2,ThO2rCa2+=0.100 nmrF=0.133 nmrCa+2/rF=0.8Fluorite Structure 螢石結構CaF2,Z12Perovskite Structure 鈣鈦礦結構BaTiO3,SrZrO3,SrSnO3Perovskite Structure 鈣鈦礦結構BaTi13Interstitial position填隙位置、間隙位置Tetrahedral position 四面體位置Octahedral position 八面體位置close-packed structure 最密堆積結構、緊密堆積結構Interstitial position填隙位置、間隙位14Crystal structureHexagonal Close-Packed(HCP)六方最密堆積ABAB.Stacking SequenceFace-Centered Cubic(FCC)面心立方ABCABC.Stacking SequencecaA sitesB sitesA sitesABCCrystal structureHexagonal Clo15Determine Crystal Structures1.Stoichiometry 化學計量lCharge Neutrality2.Cation-anion radii ratios(coordination number)3.Covalent characterDetermine Crystal StructuresSt16Ceramic Density ComputationNumber of formula units/unit cellAC:atomic weight of cation AA:atomic weight of anion VC:Volume of unit cellNA:Avogadros numberCeramic Density ComputationNum17Silicate Ceramics 矽酸鹽陶瓷Silicate Ceramics 矽酸鹽陶瓷18Silica 矽石、二氧化矽Crystalline structure of SilicaQuartz 石英Cristobalite(Crystobalite)白矽石、方矽石Tridymite 鱗石英、鱗矽石The strong Si-O bond leads to a strong,high melting temperature(1710 C)Silica 矽石、二氧化矽Crystalline stru19Cristobalite(Crystobalite)白矽石、方矽石Cristobalite(Crystobalite)白20Silica Glass 矽石玻璃fused silica or vitreous silica 熔凝矽石或玻化矽石B2O3 and GeO2Network formerCaO and Na2ONetwork modifierTiO2 and Al2O3IntermediateModifiers and Intermediates lowers the melting point and viscosity of a glassSilica Glass 矽石玻璃fused silica 21Crystalline silicon dioxideNoncrystalline silicon dioxideCrystalline silicon dioxideNon22Silicate 矽酸鹽Silicate 矽酸鹽23Two-dimensional silicate sheet structure(Si2O5)2 Two-dimensional silicate sheet24Layered SilicatesCan change the counterions(相對離子)this changes layer spacingthe layers also allow absorption of water Mica 雲母 KAl3Si3O10(OH)2Bentonite 膨土、火山黏土used to seal wellspackaged dryswells 2-3 fold in H2Opump in to seal up well so no polluted ground water seeps in to contaminate the water supplyLayered SilicatesCan change th25Structure of kaolinite clay高嶺黏土Structure of kaolinite clay高嶺26Carbon 碳Diamond 鑽石metastable state 介穩態、準穩態Graphite 石墨Fullerene 芙、芙樂、富勒、芙樂烯、富勒烯C60Buckminsterfullerenes 巴克明斯特芙樂烯 Buckyball 巴克球Carbon 碳Diamond 鑽石27Diamond cubic crystal structureDiamond cubic crystal structur28Structure of GraphiteStructure of Graphite29Structure of a C60 MoleculeStructure of a C60 Molecule30Structure of a Carbon NanotubeStructure of a Carbon Nanotube31Imperfections in Ceramic Imperfection 缺陷Electroneutrality 電中性Atomic Point DefectVacancy 空位Interstitial 填隙、間隙Defect StructureFrenkel defect 夫倫克耳缺陷Schottky defect 肖特基缺陷Stoichiometry or NonstoichiometryImperfections in Ceramic Imper32Defect StructureFrenkel defectSchottky defectDefect StructureFrenkel defect33Impurities in CeramicsElectroneutrality 電中性Solid solution 固溶體substitutional typeinterstitial typeImpurities in CeramicsElectron34Diffusion in Ionic MaterialsDiffusion in ionic materials usually occurs by a vacancy mechanismElectroneutrality 電中性Diffusion in Ionic MaterialsDi35Ceramic Phase DiagramsMgO-Al2O3Ceramic Phase DiagramsMgO-Al2O36Brittle Fracture of Ceramicsbrittle fracture 脆性斷裂plastic deformation 塑性形變fractography 斷口形像學crack 裂痕、裂紋、裂縫branch or bifurcate 分叉Brittle Fracture of Ceramicsbr37Stress-Strain BehaviorStress 應力Strain 應變flexural strength 抗彎強度、抗撓強度、撓曲強度modulus of rupture 破壞模數 fracture strength 破裂強度 bend strength 彎曲強度Stress-Strain BehaviorStress 應38Plastic Deformation Crystalline ceramicsNoncrystalline ceramicsViscosity 黏度、黏性Plastic Deformation Crystallin39
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