LECTURE 10.2LECTURE 10.2

OUTLINEOUTLINE

Weekly ReadingWeekly ReadingElectronic Properties IIElectronic Properties II

CHAPTER XXXII: SINTERING AND THE FIRING OF CLAY

CERAMICS The shaping and firing of clay is common to all early The shaping and firing of clay is common to all early

civilizations and typically represents the first successful civilizations and typically represents the first successful attempt by man to process a material—to create an engineered attempt by man to process a material—to create an engineered solid. The reactions that occur during the firing of clay are solid. The reactions that occur during the firing of clay are complex, but complex, but sinteringsintering is common to all reactions that aim to is common to all reactions that aim to consolidate materials in the absence of large scale melting. consolidate materials in the absence of large scale melting. Hence, Chapter 32 begins by describing the process of Hence, Chapter 32 begins by describing the process of sintering, and presents some rather diverse examples of the sintering, and presents some rather diverse examples of the formation of monolithic solids through sintering, such as the formation of monolithic solids through sintering, such as the snowball, sedimentary rocks, and high-tech metals and snowball, sedimentary rocks, and high-tech metals and ceramics.ceramics.

CHAPTER XXXII: SINTERING AND THE FIRING OF CLAY

CERAMICSThe chapter then focuses on the firing of clay.

The origin of clay is briefly described, as are the reactions that occur during firing. It is shown that, in addition to solid state sintering, the formation of a liquid phase at high firing temperatures can significantly enhance densification and the creation of a dense material.

CHAPTER XXXIV: THE PROCESSING OF STEEL

Steel is central to the very fabric of our Steel is central to the very fabric of our civilization. Steel provides the strength for the civilization. Steel provides the strength for the high-rise architecture of our downtowns, the high-rise architecture of our downtowns, the flexibility and durability for the nation's flexibility and durability for the nation's infrastructure, and our desire for cheap infrastructure, and our desire for cheap automobiles. Chapter 34 presents the story of automobiles. Chapter 34 presents the story of steel, from the raw materials that charge the steel, from the raw materials that charge the blast furnaces to the credit card-thick steel blast furnaces to the credit card-thick steel sheet that is provided to the automobile sheet that is provided to the automobile manufacturers in places such as Detroit.manufacturers in places such as Detroit.

CHAPTER XXXIV: THE PROCESSING OF STEEL

Chapter 34 begins with a description of the iron ores that will yield elemental iron and describes the reactions that occur in the blast furnace to produce the pig-iron and a liquid slag. It is shown that the pig-iron contains too many impurities to be of much value in the market place and that this pig-iron needs refining, or converting, to steel.

ELECTRONIC PROPERTIES IIELECTRONIC PROPERTIES II

Free Electrons and Electron Holes in Free Electrons and Electron Holes in Covalently Bonded MaterialsCovalently Bonded Materials

Motion of Free Electrons and Electron HolesMotion of Free Electrons and Electron HolesThe PhotoresistorThe PhotoresistorN-Type and P-Type Extrinsic SemiconductorsN-Type and P-Type Extrinsic SemiconductorsThe Solid-State Rectifier or DiodeThe Solid-State Rectifier or DiodeThe Solar CellThe Solar Cell

COVALENT BONDING AND COVALENT BONDING AND FREE ELECTRON/ELECTRON FREE ELECTRON/ELECTRON

HOLE PAIRSHOLE PAIRS

CREATION OF ELECTRON/ELECTRON CREATION OF ELECTRON/ELECTRON HOLE PAIRS BY LIGHT PHOTONS AND HOLE PAIRS BY LIGHT PHOTONS AND

THERMAL VIBRATIONSTHERMAL VIBRATIONS

IONIZATION ENERGIES AND IONIZATION ENERGIES AND BAND-GAP ENERGIESBAND-GAP ENERGIES

MOTION OF A FREE ELECTRON MOTION OF A FREE ELECTRON AND AN ELECTRON HOLEAND AN ELECTRON HOLE

THE PHOTORESISTOR, OR THE PHOTORESISTOR, OR THE LIGHT METERTHE LIGHT METER

N-TYPE AND P-TYPE DONOR N-TYPE AND P-TYPE DONOR IMPURITIESIMPURITIES

p-type (Group III)p-type (Group III)BBAlAlGaGaInInTlTl

n-type (Group V)n-type (Group V)NNPPAsAsSbSbBiBi

A FREE ELECTRON IN AN N-A FREE ELECTRON IN AN N-TYPE SEMICONDUCTORTYPE SEMICONDUCTOR

AN ELECTRON HOLE IN A P-AN ELECTRON HOLE IN A P-TYPE SEMICONDUCTORTYPE SEMICONDUCTOR

MOTION OF AN ELECTRON MOTION OF AN ELECTRON HOLEHOLE

FREE ELECTRON/ELECTRON FREE ELECTRON/ELECTRON HOLE MOTION IN A “DIODE”HOLE MOTION IN A “DIODE”

CURRENT/VOLTAGE CURRENT/VOLTAGE CHARACTERISTICS OF A SOLID-CHARACTERISTICS OF A SOLID-

STATE “DIODE”STATE “DIODE”

THE SOLAR CELLTHE SOLAR CELL