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, 16149 Genoa

v.buscaglia@ge.ieni.cnr.it

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)

Ceramic Si3N4 bearing parts

Radial rotor made from Si3N4 for a gas turbine engine The Porsche Carrera GT's

silicon carbide disk brake

Two Kyocera ceramic knives (Y:ZrO2)

Ceramic body armour plates (Al2O3, SiC)

Structural 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)

BaTiO3 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

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

Functional ceramics

Thick (left) and thin (right) substrates (alumina)

Pressed and extruded parts (alumina, mullite, zirconia)

Ferrites cores Microwave dielectric components

Multilayer technology used for higher performances and device miniaturization

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 ceramic capacitors: most widely used ceramic components in ME

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

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.

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

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. 19,665-673 (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. 111,031301 (2012).

J. Rodel et al., Perspective on the Development of Lead-free Piezoceramics, J. Am. Ceram. Soc. 92, 1153-1177 (2009)

T. R. Shrout & S. J. Zhang, Lead-free piezoelectric ceramics: Alternatives for PZT?, J. Electroceram. 19,111–124 (2007)

C.A. Randall et al., High Strain Piezoelectric Multilayer Actuators—A Material Science and Engineering Challenge, J. Electroceramics 14,177-191 (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. 22,2900-2918 (2010).

J. van den Brink, D. I. Khomskii, Multiferroicity due to charge ordering, J. Phys.: Condens. Matter 20,434217 (2008)

M. Winter & M.J. Brodd, What Are Batteries, Fuel Cells, and Supercapacitors?, Chem. Rev. 104,4245-4269 (2004).

A. J. Jacobson, Materials for Solid Oxide Fuel Cells, Chem. Mater. 22,660-674 (2010).

A. Orera & P. R. Slater, New Chemical Systems for Solid Oxide Fuel Cells, Chem. Mater. 22,675-690 (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. 33,1251-1261 (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 1,715-731 (1996.)

I. Reaney & D. Iddles, Microwave Dielectric Ceramics for Resonators and Filters in Mobile Phone Networks, J. Am. Ceram. Soc. 89,2063–2072 (2006).