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ChE 5700 Ceramic Powder Processing

ChE 5700 Ceramic Powder Processing. Kan-Sen Chou. Che5700 陶瓷粉末處理. Material Classification. Organic materials (small molecule, polymers) from oil/gas/coal Inorganic materials : metal (conductive), ceramic, semiconductors; from minerals Bio-materials : pollen; renewable source

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ChE 5700 Ceramic Powder Processing

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  1. ChE 5700 Ceramic Powder Processing Kan-Sen Chou

  2. Che5700 陶瓷粉末處理 Material Classification • Organic materials (small molecule, polymers) from oil/gas/coal • Inorganic materials: metal (conductive), ceramic, semiconductors; from minerals • Bio-materials: pollen; renewable source • Composites : fiber reinforced plastics, fiber reinforced metal, fiber reinforced ceramics • by functions: environmental ceramics, electronic ceramics, opto-electronic ceramics etc.

  3. Material Research • Processing what you do; innovative • Microstructure  changes in basic characteristics in material • Property  performance you desired; sometimes one may have to compromise among different properties • Example: nickel hydroxide powder to electrode to battery

  4. Course Contents (4 sections) • Introduction: importance of this subject, various products • Processing: Various methods to synthesize powder; Various techniques (steps) to process these powder into objects • Microstructure: Various characteristics of powder: size, shape, crystallinity….. • Property: strength, hardness, ..many other opto-electric properties; related to its applications

  5. Che5700 陶瓷粉末處理 Textbook • J.S. Reed, Principles of Ceramic Processing, 2nd edition, John-Wiley & Sons, Inc., 1995 • Major references: - T.A. Ring, Fundamentals of Ceramic Powder Processing and Synthesis, Academic Press, 1996. - Journal articles Notes: http://ceramic.che.nthu.edu.tw go to “上課講義” Evaluation: homework, final oral and written reports

  6. Che5700 陶瓷粉末處理 Definition of ceramics WD Kingery: The art and science of making and using solid articles which have as their essential components, and are composed in large part of inorganic, nonmetallic materials. Most common forms: oxides, carbides, nitrides, borides, sulfides; B C N O Si P S

  7. 多元化的精密陶瓷材料 Diversity of advanced ceramic materials

  8. Ceramic components of an engine (upper left counter-clock direction): Flow separation housing; regenerator shield; combustor liner; transition duct; combustion baffle; turbine backshroud; turbine stator; bolt assembly; turbine rotor; outer diffuser housing; inner diffuser housing; turbine shroud; insulation

  9. Che5700 陶瓷粉末處理 More functional ceramics in cars • Oxygen sensor ZrO2; knock sensor PZT • Backup sensor PZT; electric buzzer PZT • Thermal sensor for water temp., F3O4-CoMn2O3-NiO • Thermal sensor for exhaust gas Al2O3-Cr2O3 • Blower resistor BaTiO3 condenser BaTiO3 • Motor core Fe2O3-Mn2O3 LED GaP • EL ZnS heater for input gas BaTiO3 • Plate of hybrid IC Al2O3 • Fuel level switch Al2O3 – Cr2O3 • insulator for spark plug Al2O3 • Monolithic catalyst substrate MgO-Al2O3-SiO2

  10. From J. S. Reed, 2nd ed. Advanced alumina structural ceramics – very many applications * Different sizes/ different shapes

  11. Classification by function • Electrical - insulation, ferroelectrics, piezoelectric, fast • ion conduction, superconductors • Magnetic - soft ferrite, hard ferrite • Nuclear - fuel, cladding/shielding • Optical - transparent envelope, light memory, colors • Mechanical - structural refractory, wear resistance, • cutting, abrasive, construction • Thermal - insulation, radiator • Chemical - gas sensor, catalyst carrier, electrodes • filter, coating • Biological - structural prostheses, cement • Aesthetic - pottery, artware, tile, concrete

  12. JS Reed, 2nd ed. Refractory honeycomb cordierite catalyst support JS Reed, 2nd ed. Magnetic ceramic ferrites used in a wide variety of electrical and electronic communications systems

  13. Terra Cotta 秦皇俑 Source: Museum of Qin Terra Cotta Warriors and Horses (ancient ceramic products)

  14. From TA Ring

  15. Che5700 陶瓷粉末處理 Conventional tile production • (A) raw materials  ball mill to fine particles  de-watering (filter press)  kneading (paste)  vacuum forming  drying  glazing  sintering (tunnel kiln)  inspection  product • (B) raw materials  ball mill to fine size powders  spray dryer  press forming  glazing  sintering (roller-hearth kiln)  inspection  product

  16. Che5700 陶瓷粉末處理 Conventional Raw Materials • Major applications: construction, bathroom, kitchenware • Examples: clay – kaolin as representative, fine size hydrous aluminum silicate Al2(Si2O5)(OH)4, plasticity of suspension, can be sintered in wide range temperature • Talc: hydrous magnesium silicate; • Feldspar: anhydrous aluminum silicate, containing Na, K, or Ca – cheap water-insoluble alkali, often as flux; • Silica: often as quartz, cristobalite etc.

  17. Synthetic Materials • raw materials for fine ceramics: mostly synthetic powders, major components: SiO2, Al2O3, TiO2, ZnO, ZrO2, ferrite, titanate (BaTiO3, PZT), SiC, Si3N4, boride, CdS, ZnS, ITO, IZGO, ….. • Synthetic methods: chemical method (major), plus sol-gel method, solvent evaporation method, precursor decomposition, self-combustion, solid-state reaction method, …..  hope to get ideal powders!!

  18. Taken from Am. Cer. Soc. Bull., Aug, 1999. Markets and applications of Bayer process alumina

  19. Che5700 陶瓷粉末處理 Ceramic Processing or Ceramic Fabrication Process * Ordinary processing: powder synthesis  powder treatment  forming  sintering  final post-fabrication treatment • processing – microstructure – properties • powder synthesis size mechanical • powder treatment shape/porosity electrical • forming of objects surface area etc • etc

  20. Taken from JS Reed, p.8; • conventional alumina, sintered density98%, not transparent; next page product density 99.9%, transparent

  21. From JS Reed, 2nd ed. Mechanical, optical properties  influenced by grain size  influenced by particle size of raw materials, forming technique, sintering condition, etc. processing variables

  22. porous ceramics: filtration 、temperature resistant characteristics  influenced by composition and pore size distribution  Influenced by raw material/forming technique/sintering From JS Reed, 2nd ed.

  23. Che5700 陶瓷粉末處理 Ordinary Characteristics of Ceramics • Advantages: Inert, high strength, tolerant of high temperature, functional properties • Disadvantages: brittle, reliability (due to inhomogeneity or irregularity), reproducibility, cost and productivity • New ceramics, fine ceramics, advanced ceramics

  24. Che5700 陶瓷粉末處理 Powder Processing • Total process concept: Pn(P n-1 (…..P2(P1(S)))) • -- every processing (operation) will change some microstructure of material (material respond) to reach the final state • Intrinsic Character: (microstructure) • composition: chemical, crystal phase • structure: grain size, crystal perfection, porosity • Extrinsic (behavior) properties: • E.g.: tensile strength, magnetic permeability, thermal expansion, resistance to thermal shock, resistance to corrosion, etc.

  25. Che5700 陶瓷粉末處理 Lots of Properties • Mechanical types: strength, toughness, low creep, low friction, wear resistance, corrosion resistance, thermal shock resistance, matched thermal expansion assemblies; • Electrical/optical/magnetic types: dielectric (high or low); thermal conductivity, electrical conductivity, temperature-dependent resistivity, piezoelectric , optical absorption, chemical electrical effect, voltage-sensitive resistivity; • Others: thermal (insulation), biological, aesthetic (美學), chemical (e.g. sensor, electrode, etc.)

  26. Che5700 陶瓷粉末處理 Bioceramics (brief) • Classification: • Bio-inert (e.g. Al2O3, ZrO2); • Resorbable: calcium phosphate • Bioactive (surface reactive): hydroxyapatite (HA), bioactive glass; • combination: e.g. coating or composite • Applications: bone, teeth, joint etc. artificial materials; competitors: polymer, metal; • Desired characteristics: biocompatibility, strength (complex stress condition within human body)

  27. Che5700 陶瓷粉末處理 Examples on processing- microstructure – property • (a) grinding – equipment & grinding media & t & rotation speed  fracture mechanics of powders – morphology & size distribution – surface energy, rheology of particle in fluid • (b) sintering – T & t & atmosphere  solid state reactions, phase transformation, mass transport, grain boundary mobility – grain size & distribution, pore size & distribution, nature of grain boundary – all kinds of mechanical/chemical/electrical properties

  28. C: composition; M:microstructure; PD: process defects; SD: service defects

  29. Need to do more analysis on microstructure to improve reliability, reduce cost

  30. Che5700 陶瓷粉末處理 Origins of non-uniformity • Composition: from mixing or reaction • Particle size distribution / agglomerates • Forming process: e.g. during pressing • Sintering: e.g. temperature distribution in furnace •  non-uniformity will pass on to next step, to final product and therefore properties of products

  31. From JS Reed, 2nd ed. Common processing steps: many different operations as shown in this diagram

  32. Fig. 1.5 of the textbook by JS Reed

  33. Science of Ceramics Processing what happened on the microscale • Reactions leading to the formation of particles (e.g. chemical reaction, particle nucleation, growth,…) • dispersion of particles in solution: interfacial phenomena; • rheology during forming processes, particle packing • sintering: diffusion, grain growth, structural development, etc.

  34. Ceramic Museum in New Taipei City • website: http://www.ceramics.tpc.gov.tw • address: 新北市鶯歌文化路 200號 (02-86772727) • First Taiwan International Ceramic Arts Biannual Exhibition, 2004/2/13

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