1. Introduction to functional ceramic materials
Introduction to functional ceramic materials. Structure, properties, preparation and applications
Vincenzo Buscaglia
Istituto per l’Energetica e le Interfasi
Consiglio Nazionale delle Ricerche
Via De Marini 6, Genoa 1

2. Technical/advanced ceramics
What a ceramic is ?
From Greek word “keramos” (pottery, potter’s clay)
Inorganic nonmetallic materials obtained by the action of heat and subsequent cooling
Polycrystalline materials, single phase or multiphase (composites), sometimes with an amorphous component (glass)
Traditional ceramics
Whitewares: tableware, cookware, sanitary ware, etc.
Refractories (kiln and furnace linings for steel and glass industry)
Structural clay products (floor & roof tiles, bricks, etc.)
Fabricated from clay, quartz, feldspar (earthenware) and kaolin (porcelain)
Technical/advanced ceramics
Structural ceramics (mechanical properties: strength, toughness, hardness, creep resistance)
Functional ceramics (electric, magnetic, optical properties) 2

3. Structural ceramics Two Kyocera ceramic knives (Y:ZrO2)
Ceramic body armour plates (Al2O3, SiC)
Ceramic Si3N4 bearing parts
The Porsche Carrera GT's silicon carbide disk brake
Radial rotor made from Si3N4 for a gas turbine engine 3

4. Functional ceramics Functionality Material Applications Resistors
SiC, MoSi2, LaCrO3
Heating elements for high temperature furnaces
Thermistors
(NTCR & PTCR)
Spinels
BaTiO3
Temperature sensors, self-regulating heating elements
Dielectrics with very low losses (r = 3 -10)
Al2O3, AlN, cordierite
Substrates for electronic circuits and chip packaging
Dielectrics for microwave applications (r = 30-80)
BaTi4O9, Zr(Ti,Sn)O4, BaMg1/3Ta2/3O3,
(Ba,Sr)TiO3,
MW resonators, filters and antennas for mobile communications and GPS devices, tunable MW devices
Temperature stable dielectrics (r  100)
CaTiO3, BaO-Nd2O3-TiO2
Capacitors with temperature-independent capacitance
Dielectrics with very high dielectric constant (r  3000)
Multilayer ceramic capacitors
Piezoelectric ceramics
Pb(Zr,Ti)O3 (PZT)
Transducers, actuators and resonators
Pyroelectric ceramics
Pb(Zr,Ti)O3
IR radiation detection and imaging 4

5. Functional ceramics Functionality Material Applications
Ferroelectric ceramics
Pb(Zr,Ti)O3
SrBi2Ta2O9
Ferroelectric memories (FeRAMs)
Electrostrictive ceramics
PbMg1/3Nb2/3O3 -PbTiO3 (PMN-PT)
Actuators
Magnetic ceramics
Spinels (Ni,Zn)Fe2O4
BaFe12O19
Y3Fe5O12 (YIG)
Inductors
Permanent magnets
Microwave devices (radars)
Ionic conductors
Y:ZrO2 (YSZ)
Gd:CeO2
β-alumina
Electrolytes for solid-oxide fuel cells (SOFCs), oxygen sensors
Na-Batteries
Superconductors
YBa2Cu3O7-x (YBCO)
MgB2
Superconducting cables for magnets
Transparent ceramics
Al2O3, MgAl2O4, Y3Al5O12 (YAG)
Phosphors, optical materials for lenses and laser systems, nose cones for heat-seeking missiles, high-pressure sodium street lamps
Optoelectronic materials
LiNbO3
PLZT
Waveguides, frequency doublers, voltage-controlled optical switches, modulators 5

6. Pressed and extruded parts (alumina, mullite, zirconia)
Thick (left) and thin (right) substrates (alumina)
Microwave dielectric components
Ferrites cores 6

7. 7

8. Low Temperature Co-fired Ceramics (LTCC) Ceramic Multilayer Substrates
Monolithic Multilayer Ceramic Capacitors (modified BaTiO3)
Ceramic resonators (SiO2, PZT, BaMg1/3Ta2/3O3)
Thermistors (NTCR: spinels; PTCR: modified BaTiO3)
Ceramic filters (BaMg1/3Ta2/3O3, Zr(Sn,Ti)O4)
Cheap ferrite beads (hexaferrites BaFe12O19)
Multilayer piezoelectric ceramic actuators for diesel injection system (PZT – PbZrxTi1-xO3)
Pyroelectric Infrared sensor (PZT)
SAW filter (SIO2, LiNbO3, LiTaO3)
Multilayer technology used for higher performances and device miniaturization

9. Multilayer ceramic capacitors: most widely used ceramic components in ME9

10. Microstructure of ceramics
Glossary: grains, grain boundaries, pores, secondary phases, domain walls, relative density, grain size, grain size distribution, texture, etc.
Fully dense 99% Al2O3, transparent
Partially porous 99% Al2O3, transparent
Liquid-phase sintered 96% Al2O3 with secondary glassy phase
Further details: Classification&Microstructure.ppt

11. Outlook of the course
Introduction. Why a course on functional ceramics? (Introduction.ppt)
Processing of ceramic materials: forming and sintering (Processing.ppt).
Structure and properties of grain boundaries. Nanoceramics (GrainBoundaries.ppt).
Ceramics for electronics: ferroelectric and piezoelectric ceramics, dielectrics with high dielectric constants (BaTiO3, PbZrxTi1-xO3, (K,Na)NbO3)
(Ferroelectrics.ppt, Piezoelectrics.ppt)
-Multilayer ceramic capacitors. Miniaturization of devices and related issues.
-Piezoelectric actuators and transducers.
-Lead-free materials.
Multiferroic materials (BiFeO3, magnetoelectric composites): a challenge for materials science. (Multiferroics.ppt)
Ceramics for energy: (SOFC.ppt, MIEC.ppt)
-Ionic and mixed high-temperature conductors (Y:ZrO2, Gd:CeO2, (La,Sr)MnO3)
-Solid-oxide fuel cells.
-Ceramic membranes for gas separation.

12. Required background
General background in physics, chemistry and materials science.
Knowledge of most common crystal structures (fluorite, spinel, perovskite).
Perovskites.ppt
Defects and defect chemistry in oxides, extended defects, doping, p- and n- type semicondutors, defect chemistry and electrical conductivity.
Defects.ppt
Electric and dielectric properties of crystalline solids: polarization, complex dielectric permittivity, ac dielectric properties, impedance, dielectric relaxation.
Dielectrics.ppt
Fundamentals of solid-state magnetism

13. Suggested readings Books
A.J. Moulson & J.M. Herbert, Electroceramics, Chapman & Hall.
W.D. Kingery, H.K. Bowen, D.R. Uhlmann, Introduction to Ceramics, John Wiley & Sons.
Review papers
F. Ernst, O. Kienzle and M. Rühle, Structure and Composition of Grain Boundaries in Ceramics, J. Europ. Ceram. Soc. 19, (1999).
S. von Alfthan et al., The Structure of Grain Boundaries in Strontium Titanate: Theory, Simulation and Electron Microscopy, Annu. Rev. Mater. Res. 40,557–99 (2010).
G. H. Haertling, Ferroelectric Ceramics: History and Technology, J. Am. Ceram. Soc. 82,797–818 (1999).
D. Damjanovic, Ferroelectric, dielectric and piezoelectric properties of ferroelectric thin films and ceramics, Rep. Prog. Phys. 61,1267–1324 (1998).
L. Jin, F. Li, S. Zhang, Decoding the Fingerprint of Ferroelectric Loops: Comprehension of the Material Properties and Structures, J. Am. Ceram. Soc. 97,1–27 (2014)
A.K. Tagantsev et al., Ferroelectric Materials for Microwave Tunable Applications, J. Electroceramics 11, 5–66 (2003).
S. Zhang & F. Li, High performance ferroelectric relaxor-PbTiO3 single crystals: Status and perspective, J. Appl. Phys. 111, (2012).
J. Rodel et al., Perspective on the Development of Lead-free Piezoceramics, J. Am. Ceram. Soc. 92, (2009)
T. R. Shrout & S. J. Zhang, Lead-free piezoelectric ceramics: Alternatives for PZT?, J. Electroceram. 19,111–124 (2007)

14. C.A. Randall et al., High Strain Piezoelectric Multilayer Actuators—A Material Science and Engineering Challenge, J. Electroceramics 14, (2005).
M. Fiebig, Revival of the Magnetoelectric Effect, J. Phys. D.: Appl. Phys. 38,R123-R152 (2005)
C.A.F. Vaz et al., Magnetoelectric Coupling Effects in Multiferroic Complex Oxide Composite Structures, Adv. Mat. 22, (2010).
J. van den Brink, D. I. Khomskii, Multiferroicity due to charge ordering, J. Phys.: Condens. Matter 20, (2008)
M. Winter & M.J. Brodd, What Are Batteries, Fuel Cells, and Supercapacitors?, Chem. Rev. 104, (2004).
A. J. Jacobson, Materials for Solid Oxide Fuel Cells, Chem. Mater. 22, (2010).
A. Orera & P. R. Slater, New Chemical Systems for Solid Oxide Fuel Cells, Chem. Mater. 22, (2010).
J. Sunarso et al., Mixed ionic–electronic conducting (MIEC) ceramic-based membranes for oxygen separation, J. Membrane Science 320,13–41 (2008)
S. Baumann et al., Manufacturing strategies for asymmetric ceramic membranes for efficient separation of oxygen from air, J. Europ. Ceram. Soc. 33, (2013).
A. Feteira, Negative Temperature Coefficient Resistance (NTCR) Ceramic Thermistors: An Industrial Perspective, J. Am. Ceram. Soc., 92, 967–983 (2009).
W. Wersing, Microwave ceramics for resonators and filters, Current Opinion in Solid State & Materials Science 1, (1996.)
I. Reaney & D. Iddles, Microwave Dielectric Ceramics for Resonators and Filters in Mobile Phone Networks, J. Am. Ceram. Soc. 89,2063–2072 (2006).