BARC-16: Using Gibb’s Phase rule for a Binary Eutectic alloy, the maximum number of Phases that can co-exist at equilibrium are 4 (F=0, P = C+2 = 4). Then at the Eutetic point there should be 4 phases but we find only 3? Explain

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The Gibbs phase rule is F=c-p+2. Here, the two represent two variables. One is temperature and another one is pressure. We draw the phase diagram at constant pressure. So the gibbs phase rule is change into F=c-p+1. This is called condensed phase rule. If we use this equation at eutectic point, we wRead more

The Gibbs phase rule is F=c-p+2. Here, the two represent two variables. One is temperature and another one is pressure. We draw the phase diagram at constant pressure. So the gibbs phase rule is change into F=c-p+1. This is called condensed phase rule. If we use this equation at eutectic point, we will get only three phases.

See lessIn a binary system pressure is kept as constant.So tje Gibbs phase rule formula changed to F=C-P+1 Only. Where F=0 at the invariant reaction lines so P=C-F+1 is formula for unknown phases P=2-0+1=3 Phases are 3 in Binary eutectic alloy i.e liquid , Austenite,Fe3C(Cementite)

In a binary system pressure is kept as constant.So tje Gibbs phase rule formula changed to F=C-P+1 Only.

Phases are 3 in Binary eutectic alloy i.e liquid , Austenite,Fe3C(Cementite)

See lessF = C-P+2 can not be applied at the eutectic point because while drawing a phase diagram pressure is kept constant The condensed phase rule is used . F = C-P+1 At the eutectic point, F = 0 , C = 2 and thus p =3. Maximum 3 phases exist at equilibrium.

We use condensed phase rule for binary systems. Pressure being fixed the equation we use is F+P=C+1; which at eutectic point gives 3 phases.

We use condensed phase rule for binary systems. Pressure being fixed the equation we use is F+P=C+1; which at eutectic point gives 3 phases.

See lessBecause in the formula for variables temperature and pressure '2' is used but at eutectic point temperature remains no longer a variable, it becomes constant hence we should use '1' instead of '2' for taking only pressure as variable, then we'll get no. of phases 3.

Because in the formula for variables temperature and pressure ‘2’ is used but at eutectic point temperature remains no longer a variable, it becomes constant hence we should use ‘1’ instead of ‘2’ for taking only pressure as variable, then we’ll get no. of phases 3.

See lessF= C-P +2 is used when there are two variables in the system i.e Pressure and Temperature. But binary phase diagrams are drawn making pressure constant making F=C-P+1. This gives 3 phases at eutectic point.

F= C-P +2 is used when there are two variables in the system i.e Pressure and Temperature. But binary phase diagrams are drawn making pressure constant making F=C-P+1. This gives 3 phases at eutectic point.

See lessGibb's phase rule is F=C-P+2. Here 2 is for two variables temp and pressure. C is for components and p is for no of phases present and F is for degree of freedom . In a binary phase diagram pressure is considered as constant. So, Gibb's phase rule for a binary system is F=C-P+1. In an eutectic phaseRead more

G=C+P-1 should be used in this case since Pressure is kept constant.

G=C+P-1 should be used in this case since Pressure is kept constant.

See lessThe variable "2" in the formula represents Pressure and temperature. In our Binary Eutectic system, we are taking pressure as constant, so it will not be variable. So formula became: F=C-P+1 By using this formula, At the eutectic point F=0, C=2 P=C-F+1 P= 2-0+1 No. of. phases possible in Eutectic poRead more

The variable “2” in the formula represents Pressure and temperature.

In our Binary Eutectic system, we are taking pressure as constant, so it will not be variable. So formula became:

F=C-P+1By using this formula, At the eutectic point F=0, C=2

P=C-F+1

P= 2-0+1

No. of. phases possible in Eutectic point

See lessP= 3this is because the pressure is fixed..so we have to apply thr condensed phase rule...f=c-p+1

this is because the pressure is fixed..so we have to apply thr condensed phase rule…f=c-p+1

See lessThe fourth phase is the coagulated one, of all the three existing phases. I pay regards to my mentors (Prof. GSU & Prof. RKD) by replying this question.

The fourth phase is the coagulated one, of all the three existing phases. I pay regards to my mentors (Prof. GSU & Prof. RKD) by replying this question.

See lessBecause only pressure is variable here , not the temperature (it is constant here along eutectic line). So F=C- P+1 is used( also known as condensed phase rule). For your information, F=C- P+2 is applicable only when there are 2 varients from the set of temperature, pressure and composition.

Because only pressure is variable here , not the temperature (it is constant here along eutectic line). So F=C- P+1 is used( also known as condensed phase rule).

For your information, F=C- P+2 is applicable only when there are 2 varients from the set of temperature, pressure and composition.