Fundamental of Materialogy

(Binding Bond)

:()

Chap. 2 Crystal structures1. Lattice, unit cell, basis, and Crystal structuresIdeal crystals: Periodicity & long-range order ( x1d2d3d t1t3t2(Primary unit cell: the smallest unit)

:a,b,c)size

,,)shape2. Coordinatesxyzabcxyzgab

3. 7(syngonies)14Bravais

14Bravais7 4 sCbF

abc aP 1TriclinicPearson

Monoclinicabc ==90abcmP mC 2

oP 1 oC 2 oF 4 oI 2abc==90

hP Hexagonala1=a2a3c=90 =120a1a2a3

hR1 Rhombohedrala=b=c, ==90

tP1tI2

Tetragonala=bc, ==90

cP1cI2

4 Cubica=b=c ==90

4. Miller indexABC1

x y zn1 n2 n3 (n1 n2 n3) Weiss

hx + ky + lz = j (h k l) Miller OOA= n1 aOB= n2 bOC= n3 c 1

(h k l) Miller{h k l} e.g., {100}=(100)+(010)+(001) (For cubic lattice)

n1n2n3hkl(h k l)111111111333111111100100111001001010010123632632-11-110 10

1 2

2xyzrr = U x + V y + W zuvw [U V W] Millere.g., x-axis [100] y-axis [010] z-axis [001][111][110] e.g., =[100]+[010]+[001] +[100]+[010]+[001] (For cubic lattice)

5 .5.1 (hkil)

5.1 [uvtw][uvtw][UVW]

11. 3. {100}{110}{111}{112}2.

Structure Characteristic of Metal & Alloy BCC-FeCrWMoV a 8

FCC FeCu Al AgAuPbNi 120.74

HCP MgZnBeCd 120.74

k0.686832

CSiOSiC, SiO2

* 1.

1.1

NaClNaClNa+(Mg2+)Cl-(O2-)

O2+Zr4+ZrO2Zr4+O2+(1/4,1/4,1/4)ZrO2(CaF2)

O2-Al3+EmptyholeAl2O3O2+Al3+1/3

21FeONaClO2-FCCFe2+ rFe2+=0.074nm, rO2-=0.14nma. a b. FeOc. FeOd. FeO5.6 g/cm3FeO1-x

Crystal defects

e.g., Ruby Cr-doped Al2O3 B-doped Si: p-type semiconductor P-doped Si: n-type semiconductor 1) 0-d ()

()

e / h

1d ( dislocation)

2d/ ()

2) T>0 K) ()

3 ( intrinsic point defects)T E () E > E (/) ()Frenkel MM VM + Mi M X:MX VM + VX Schottky

VM M Mi M MXXM : (VMVX) : LM LM : e , h VM M M+ VM VM + e 4 Kroger-Vink MX

Kroger-Vink MX : VX X + X- VX VX + h PM VC P x i Max. C = P P Vi = 0

5 A B + C P

C

PPPC V=0 Sci = 0 Aa Bb NA: NB= a:b

* 6Ne N Ev k T A1~101 T -- C

* 71~2 0.5

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