3.5 공석점 ( )을 갖는 2성분계

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① * An invariant point composed solely of crystalline phases, at which the phase reaction on change of heat content at constant temperature results in a change in proportions of the solid phases exactly analogous to that at a eutectic point, in which one of the phases is liquid.

* Eutectoid - solid phase in equation with two solid phases

* 공석반응 (eutectoid reaction) : 냉각시 단상의 고상이 2상의 고상으로 cooling

δ ⇄ α + ε

heating

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② 8 wt% CaO와 92 wt% ZrO2인 융체를 냉각 시 이 계에서 등조성선 연구

ZrO2의 공석반응 (eutectoid reaction) :

1000℃, c 850℃, c (

⇄ + ) ( ⇄ + )

h h

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Temp.

(℃)

Property (Phase)

% (Phase)

% Composition of Phase

Analysis ZrO2 CaO

2500

( )mm melt ( ) ZrO2 ( ) ( ) CaO ( ) ( )

( ) mm ( )crystals ( ) ZrO2 ( ) ( ) CaO ( ) ( )

92.0 8.0

1500

( ) mm melt ( ) ZrO2 ( ) ( )

CaO ( ) ( )

( ) mm ( ) crystals ( ) ZrO2 ( ) ( ) CaO ( ) ( )

92.0 8.0

850+

( )mm ( ) crystals ( ) ZrO2 ( ) ( ) CaO ( ) ( ) ( ) mm ( ) crystals ( ) ZrO2 ( ) ( )

CaO ( ) ( ) 92.0 8.0

850-

( )mm ( ) crystals ( ) ZrO2 ( ) ( ) CaO ( ) ( ) ( ) mm ( ) crystals ( ) ZrO2 ( ) ( )

CaO ( ) ( ) 92.0 8.0

25

( )mm ( ) crystals ( ) ZrO₂ ( ) ( )

CaO ( ) ( ) ( ) mm ( ) crystals ( ) ZrO2 ( ) ( )

CaO ( ) ( ) 92.0 8.0

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3.6 기타 2성분계 반응

① Peritectoid (포석 반응)

- An invariant point composed entirely of crystalline phases, at which the phase reactions on change of heat content at constant temperature are exactly analogous to those at a peritectic point, in which one of the phases is liquid.

- 한 고상이 고상과 반응하여 새로운 고상을 만듬 ( )

② Monotectic (편정 반응)

The reversible transition, on cooling, of a liquid to a mixture of a second liquid and a solid Liquid1 ⇄ Liquid2 + Solid

-냉각중의 액상이 처음의 액상과는 다른 조성의 액상과 고상으로 등온·가역적으로 변태하는 과정 -64%Cu-36%Pb 조성의 L1 액상은 955℃에서 α-Cu(100%Cu)가 편정되고 납이 풍부한 L2 액상 (13%Cu-87%Pb)과 공존함

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③ Congruently Melting (분해 용융점) Compound

is one that when it is heated, will melt to a liquid of its own composition.

④ Incongruently Melting (비분해 용융점) Compound

is a solid phase which when heated does not melt to a liquid of its own composition, it melts to a liquid and another solid, e.g.