晶体缺陷作业

1

什么叫肖特基缺陷和弗兰克耳缺陷？用

Kroger-Vink

记号分别描述

AgBr

中的

MgO

中的肖特基缺陷形成的缺陷 化学方程，写出

ZnO

中掺杂

Al

2

O

3

空位补偿和 电子补偿的缺陷化学方程。

2

If cupric oxide (CuO) is exposed to reducing atmospheres at elevated temperatures,

some of the Cu

2+

ions will become Cu

+

.

(a)

Under

these

conditions,

name

one

crystalline

defect

that

you

would

expect

to

form in order to maintain charge neutrality.

(b) How many Cu

+

ions are required for the creation of each defect?

(c)

How

would

you

express

the

chemical

formula

for

this

nonstoichiometric

material?

3 (a) Suppose that Li

2

O is added as an impurity to CaO. If the Li

+

substitutes for Ca

2+

,

what kind of vacancies would you expect to form? How many of these vacancies

are created for every Li added?

(b) Suppose that CaCl

2

is added as an impurity to CaO. If the Cl

-

substitutes for O

2-

,

what kind of vacancies would you expect to form? How many of the vacancies are

created for every Cl

-

added?

4

纯铁的空位形成能为

1.5X10

-19

J/atom

，

将纯铁加热至

850

℃后激冷至室温

20

℃

,

若高温下的空位全部保留，试求过饱和空位浓度与室温平衡空 位浓度的比值。

5

已知铜的晶体结 构为

fcc,

点阵常数

a=0.225 nm

，切变模量

G

?

< br>4

?

10

10

< br>N

?

m

?

2

，试

分别计算柏氏矢量为

[

10

1

]

a

2

a

a

a

[

11

1

]

[

111

]

[

121

]

的位错应变能。

< /p>

3

2

6

6

在图示的

Cu

晶界上有一双球冠形第二相，< /p>

已知

Cu

的大角度晶界能为

0

.

5

J

< br>?

m

2

，

(1)

分别计算当

?

?

60

o

,

?

?

90

o

< br>时

Cu

与第二相之间的相界面能；