Discussion on MATERIALS SCIENCE, MAGNETISM, electrical conductivity, Metallurgy and CERAMICS
1
in the IRON CARBON DIAGRAM Why solubility of carbon in iron decreases with increase in temperature ?
2
Pearlite has different % of cementite and ferrite
Why cementite and ferrite are of equal length in pearlite ?
3
In the IRON CARBON DIAGRAM delta ferrite exists at higher temperature as compared to austenite.
Delta ferrite has packing efficiency of 68 % and austenite has packing efficiency of 74 %.
In the IRON CARBON DIAGRAM Why solubility of carbon in delta ferrite is less than austenite ?
4
Write electronic configuration of iron, nickel and copper
Iron and nickel have more VALENCE electrons than copper.
Iron and nickel have more FREE electrons than copper.
WHY copper has higher ELECTRICAL CONDUCTIVITY than iron and NICKEL ?
5
What is the BRAVAICE LATTICE for a diamond cubic unit cell ?
6
How are the atoms of iron and carbon arranged in a unit cell of cementite
7
Iron has unpaired electrons and it is attracted by magnet
Sodium and potassium have unpaired electrons but why they are not attracted by magnet
8
Can you PLEASE derive the value of c / a ratio for a HCP or hexagonal close packed unit cell
9
Can you PLEASE derive the value of packing efficiency for a HCP or hexagonal close packed unit cell
10
what is the difference between screw dislocation and twist boundaries
11
What is the difference between edge dislocation and twin boundaries
12
How the equation for non steady or unsteady heat transfer has been derived
13
How the equation for non steady or unsteady diffusion has been derived
14
How these methods have been derived
A
Gauss Jordan method
B
Gauss siedel method
C
Jacobi method
15
What is Scarborough criterion for solving a set of more than 1 Linear equations
16
How Scarborough criterion has been derived
17
What is the difference between crystal system and crystal structure
18
There are how many crystal systems
19
There are how many crystal structures
20
What is the crystal system and crystal structure for a diamond cubic unit cell
I have guessed a reason but I am not sure whether I am right or wrong
Let us start OUR discussion
1
VALENCE electrons of a metal that we see in electronic configuration do not stay with the atom of metal.
2
Metal is a collection of positive charged ions surrounded by a sea of free electrons
3
Electronic configuration of iron is 4s2 , 3d6
Crystal of iron is a collection of ions with Electronic configuration 3s2, 3d6
In this ion 3d has 4 unpaired electrons
This could be the reason for iron to be attracted towards magnet
4
Electronic configuration of sodium is 3s1, 2p6
Crystal of sodium is a collection of ions with Electronic configuration 2s2, 2p6
THIS ion does NOT have unpaired electrons
This could be the reason for sodium to NOT get attracted towards magnet.
SHANTANU AGRAWAL
. ...........
You are almost correct. The only thing iron has a special characteristics that its ions align their magnetic moments with neighbours. The attraction that we generally see between iron pieces and magnet is due to this "ferromagnetic" character.
Unpaired or paired electrons give dia and para magnetism. The attraction etc is too weak to be observed in normal set ups.
Good thinking.
Best wishes.
Harish
www.hcverma.in
Ex-Professor of Physics
IIT Kanpur
1
www.hcverma.in
2
www.facebook.com/hcvermaphysics
3
https://www.youtube.com/channel/UCST7O07V0HwBkK_wCB6EB5g
.............
Don't know who I am communicating with. But anyways.
Magnetism in most metals is not seen this way. Check out Pauli's
paramagnetism. In the free electron bands, the up and down spins cancel
and there is no permanent magnetism. Only in a field, the bands move and
unbalanced spin is caused, leading to small value of magnetism, this is
para magnetic behavior.
Some metals, however, are different. Like, Fe, Co, Ni....their magnetic
properties need to be described through quantum mechanical exchange
integral...there is no other way to understand the phenomena. This
exchange integral decides how spins on atoms in a crystal arrange
themselves. Accordingly the total spin will manifest, and even in
absence of a field, you will have residual magnetism.
hope this helps.
Deepak
Professor
Materials Science and Engineering
& National Center for Flexible Electronics (FlexE)
Indian Institute of Technology
Kanpur 208016, India
in the IRON CARBON DIAGRAM Why solubility of carbon in iron decreases with increase in temperature ?
2
Pearlite has different % of cementite and ferrite
Why cementite and ferrite are of equal length in pearlite ?
3
In the IRON CARBON DIAGRAM delta ferrite exists at higher temperature as compared to austenite.
Delta ferrite has packing efficiency of 68 % and austenite has packing efficiency of 74 %.
In the IRON CARBON DIAGRAM Why solubility of carbon in delta ferrite is less than austenite ?
4
Write electronic configuration of iron, nickel and copper
Iron and nickel have more VALENCE electrons than copper.
Iron and nickel have more FREE electrons than copper.
WHY copper has higher ELECTRICAL CONDUCTIVITY than iron and NICKEL ?
5
What is the BRAVAICE LATTICE for a diamond cubic unit cell ?
6
How are the atoms of iron and carbon arranged in a unit cell of cementite
7
Iron has unpaired electrons and it is attracted by magnet
Sodium and potassium have unpaired electrons but why they are not attracted by magnet
8
Can you PLEASE derive the value of c / a ratio for a HCP or hexagonal close packed unit cell
9
Can you PLEASE derive the value of packing efficiency for a HCP or hexagonal close packed unit cell
10
what is the difference between screw dislocation and twist boundaries
11
What is the difference between edge dislocation and twin boundaries
12
How the equation for non steady or unsteady heat transfer has been derived
13
How the equation for non steady or unsteady diffusion has been derived
14
How these methods have been derived
A
Gauss Jordan method
B
Gauss siedel method
C
Jacobi method
15
What is Scarborough criterion for solving a set of more than 1 Linear equations
16
How Scarborough criterion has been derived
17
What is the difference between crystal system and crystal structure
18
There are how many crystal systems
19
There are how many crystal structures
20
What is the crystal system and crystal structure for a diamond cubic unit cell
I have guessed a reason but I am not sure whether I am right or wrong
Let us start OUR discussion
1
VALENCE electrons of a metal that we see in electronic configuration do not stay with the atom of metal.
2
Metal is a collection of positive charged ions surrounded by a sea of free electrons
3
Electronic configuration of iron is 4s2 , 3d6
Crystal of iron is a collection of ions with Electronic configuration 3s2, 3d6
In this ion 3d has 4 unpaired electrons
This could be the reason for iron to be attracted towards magnet
4
Electronic configuration of sodium is 3s1, 2p6
Crystal of sodium is a collection of ions with Electronic configuration 2s2, 2p6
THIS ion does NOT have unpaired electrons
This could be the reason for sodium to NOT get attracted towards magnet.
SHANTANU AGRAWAL
. ...........
You are almost correct. The only thing iron has a special characteristics that its ions align their magnetic moments with neighbours. The attraction that we generally see between iron pieces and magnet is due to this "ferromagnetic" character.
Unpaired or paired electrons give dia and para magnetism. The attraction etc is too weak to be observed in normal set ups.
Good thinking.
Best wishes.
Harish
www.hcverma.in
Ex-Professor of Physics
IIT Kanpur
1
www.hcverma.in
2
www.facebook.com/hcvermaphysics
3
https://www.youtube.com/channel/UCST7O07V0HwBkK_wCB6EB5g
.............
Don't know who I am communicating with. But anyways.
Magnetism in most metals is not seen this way. Check out Pauli's
paramagnetism. In the free electron bands, the up and down spins cancel
and there is no permanent magnetism. Only in a field, the bands move and
unbalanced spin is caused, leading to small value of magnetism, this is
para magnetic behavior.
Some metals, however, are different. Like, Fe, Co, Ni....their magnetic
properties need to be described through quantum mechanical exchange
integral...there is no other way to understand the phenomena. This
exchange integral decides how spins on atoms in a crystal arrange
themselves. Accordingly the total spin will manifest, and even in
absence of a field, you will have residual magnetism.
hope this helps.
Deepak
Professor
Materials Science and Engineering
& National Center for Flexible Electronics (FlexE)
Indian Institute of Technology
Kanpur 208016, India
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