Questions tagged [metals]
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405
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Consequences of fusing metallic glasses
I have come across some information about metallic glasses which has brought up questions. I have read that due to the need for high cooling rates generally, quantities of metallic glass are only ...
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0answers
12 views
Resources for materials science (inconel/alloys)
I am doing a project on the physics of the spaceX raptor engine. I believe it is made out of a certain type of inconel alloy. I want to understand why this alloy has the properties that it does, but I ...
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1answer
48 views
Why doesnt equipment melt during manufacturing? [closed]
During many manufacturing process, the materials worked need to reach temps above the melting point of many common materials used in equipment.
How is the issue of equipment melting avoided?
Ex, how ...
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4answers
378 views
Can we say that iron on heating is a fluid?
When iron is being put on fire, its forces with other atoms starts to break. We know a solid has more atoms and less spaces between them while liquids have more space as compared to solids (Also means ...
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1answer
32 views
Can electrons come out due to photoelectric effect from any where else than the surface? [closed]
Can electrons come out due to photoelectric effect from any where else than the surface? Like what can the electrons only from the surface come out.
For a scene,
suppose a light beam of sufficiently ...
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0answers
14 views
Ultrasonic waves through metals
Might ultrasonic cleaning process/exposure influence or change the acoustic/resonance of a solid silver or solid gold flute?
Might ultrasonic cleaning process/exposure weaken or damage parts of that ...
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1answer
25 views
Ferromagnetic field near a ring in Earth's magnetic field
Let's say I am trying to find out the effect that an iron ring has on the Earth's magnetic field (approximated to a uniform field at infinity). Can I solve it in 4 steps:
Find the magnetic field due ...
0
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1answer
21 views
How is the main shape of Nitinol made?
I understand that Nitinol is a shape-memory alloy, such that it "reforms to its original shape" when heated to its transformation temperature. But what I don't understand is, how is the ...
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0answers
27 views
Why are linear diffusion graphs limited to a max and min value. Graph shown in link
This is the graph
https://prnt.sc/vpwcz6
I have tried various things to understand why the limits are the way they are for the specific metals. I tried to check if the limit is their melting point but ...
0
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1answer
49 views
Why ferroelectric material needs to be insulating?
Is it necessary for a ferroelectric material to be insulating?
Is it possible for a metal to be ferroelectric?
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2answers
39 views
Do the ideas of Bloch wavefunction and Bragg scattering of electrons which apply to crystals also apply to liquid Mercury?
Do the ideas of Bloch wavefunction and Bragg scattering of electrons which apply to crystals also apply to liquid Mercury ?
Why is it that electrons in the liquid are not localised by the disordered ...
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0answers
19 views
Do metal alloys exist with work function of ~1.4eV?
I am wondering if metal alloys with a work function of between 1.1-1.7eV (ideally 1.4eV) exist?
Some information exists on photoelectric work functions of metals here and here. Cesium seems to have ...
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22 views
Plasma frequencies of metals
The following is in relation to metal plasma.
The dielectric constant according to the Drude-Lorentz model is given by (equation 1):
Furthermore according to the Mark Fox book on Optical properties ...
0
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1answer
24 views
Metallic bonds get weaker during electrostatic induction?
If the cations are held together by the sea of electrons (metallic bonding), and if we apply electrostatic induction then what happens to the region of atoms that have a deficit of electrons? Are ...
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0answers
36 views
Dielectric constant or permitivity of copper
I'm trying to simulate a capacitor made of copper plates in comsol multiphysics. What is the value that I should use for the dielectric constant or permittivity of the copper plates? I've read that ...
1
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2answers
63 views
Why are iron and copper used more than other materials to make cooking pots?
Why are iron and copper used more than other materials to make cooking pots?
3
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1answer
50 views
Low temperature resistance of metal
Is there any intuitive explanation of why resistivity of metal goes as $T^5$ at low temperature?
The Debye theory gives that the phonon distribution goes as $n(\omega)\sim T $ at higher temperature ...
1
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1answer
28 views
What are the north side and south side magnetic metals called?
What are the two metals that cause the repel force of a north side magnet, and the attract force force of a south side magnet?
0
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1answer
34 views
How do you calculate the theoretical work function of an alloy?
Given a combination of metals or metals combined with one or more other elements, how do you calculate the theoretical work function of the alloy?
3
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1answer
77 views
Materials-science: why anyone telling that high temperature is bad for knifes? (even if this is 45-60 celsius degrees)
As I know tempering of hardened metal must be at temperature close to 150 celsius degrees.
So why exist so widespread idea that you must not use (good) knifes to cut hot products or to wash it in hot ...
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1answer
22 views
Does metallic bond increase with the increase of atoms?
So, metallic bond doesn't form between two atoms, it forms when there are a large number of atoms.
However, the establishment of metallic bond was statistical, thus there might be a time where ...
1
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1answer
32 views
Is solar radiation at earth's surface sufficient to eject electrons from aluminum?
Is solar radiation at earth's surface sufficient to eject electrons from aluminum?
2
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2answers
56 views
What causes the photoelectric vs photovoltaic effect?
In the photoelectric effect, electrons are physically ejected from the material. In the photovoltaic effect, electrons are knocked out of their atomic orbitals but remain within the material.
What ...
2
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0answers
22 views
Rutherford scattering experiment, part 2
This question is a continuation of my previous question Rutherford scattering experiment, part 1 , but can be considered independently.
Around 1906-1914 several classical experiments on scattering of $...
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1answer
52 views
Rutherford scattering experiment, part 1
Around 1906-1914 several classical experiments on scattering of $\alpha$-particles on gold and platinum foils have been performed by Rutherford, Geiger, and Marsden. In standard literature on the ...
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6answers
4k views
Why do metals have free electrons?
Throughout my highschool classes, I have been made to learn that metals have free electrons that's why they are able to conduct electricity.. But I never understood why. Is that related to metallic ...
5
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3answers
158 views
Why is the heat flow in metals slower than the current flow?
When we apply a voltage across a metallic conductor, the current starts to flow almost instantaneously. But when a temperature difference is established across the same conductor, the flow of heat is ...
3
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1answer
68 views
(Fundamental) difference of Seebeck effect for metals and semiconductors
In which way is the Seebeck effect different for semiconductors from metals and why is it greater? What is the difference in the underlying physical principle?
My knowledge so far is: Bring two ...
3
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1answer
60 views
What is plasmon really? Is it a charge density wave of electron gas or an EM wave that exists across the metal surface?
Sometimes plasmons are defined as collective plasma oscillations of the free electron gas in a metal. Therefore, plasmons must be a periodic modulation of electron charge density in the metal. But ...
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1answer
77 views
Screened Coulomb potential in metals
One of the reasons why we can neglect electron-electron interactions in metals is the fact that their coulomb interaction is screened. I'm confused about the nature of this screening. In the ...
12
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1answer
287 views
Why is crystalline graphite black yet shiny?
I am unable to find images of pure crystalline graphite with high confidence, but based on various sources I believe that it should actually be both black and shiny, in the sense that it reflects much ...
1
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2answers
47 views
The Electric Pressure Bomb: Can a conductor rupture due to its own electric pressure?
So I conducted a though experiment where I take a hollow spherical conductor and beef it up with a lot of electric charge. Here, I have ignored the ionization of air due to that huge amount of charge. ...
4
votes
3answers
65 views
How do electrons in metals manage to have zero acceleration in constant $E$ field (as in a DC circuit)?
From Newton's second law, a charged particle driven by a constant electric field should move with a constant acceleration. But electrons in a circuit acquire a steady average velocity which gives rise ...
0
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0answers
30 views
Is there an easy way to predict whether a given element will crystallise in the FCC or in the HCP structure?
I noticed, reading the solid state physics book by Ibach & Lüth, that the majority of elements crystallize in a handful of space groups:
I highlighted face-centered cubic (FCC) structures in ...
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1answer
41 views
What does work function of metal exactly mean in photoelectric emission? [duplicate]
When a metal surface is illuminated with light of appropriate frequency so as to cause photoelectric emission, when does the work function of the metal come into play? Is it the energy required to ...
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0answers
36 views
Does magnetism of metals increase when they are irradiated?
Metals have magnetic properties because they are crystal structures with unpaired electrons moving around through them, these unpaired electrons have a net spin. Does irradiating a metal increase the ...
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0answers
18 views
Work function and surface and lattice binding energy
How work function and surface and lattice binding energy are related in a metal?
I need to estimate with SRIM the changes of the work function of a gold slab after bombardment of ions, but SRIM ...
0
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1answer
45 views
Deriving Drude Theory from Plasma Fluid Equations
Does anyone have experience in looking at Drude theory from the perspective of plasma physics instead of the standard, condensed-matter, "electrons in a metal" sort of thing and can point ...
1
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1answer
90 views
How do I compute the cohesive energy of a 1D Solid (in Tight Binding) due to electrons?
The cohesive energy of a solid is the (average) energy required to isolate the atoms of a solid, which means it's given by the difference between by the energy of solid and the energy of the isolated ...
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2answers
42 views
Explanation of the concavity of conduction band and valence band of semiconductors at $k=0$
For semiconductors, the conduction band is often drawn with a positive concavity at $k=0$ while the valence band below it is drawn with a negative concavity at $k=0$. Why is this figure never flipped ...
8
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1answer
409 views
Physical significance of electrons with negative effective mass. Are they holes or what?
For metals,
the conduction band is less than fully filled,
the effective mass $m^*=\hbar^2\Big(\frac{d^2E}{dk^2}\Big)^{-1}$ is positive for the interval $k\in[-\frac{\pi}{2a},+\frac{\pi}{2a}]$ of ...
10
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2answers
705 views
Why do group II elements conduct?
Looking at the periodic table, group II elements like magnesium are known to be metallic, and yet they have full outer shells. So this means they should have full (valence) bands.
Now, last time I ...
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1answer
46 views
Why is the dielectric constant of copper plate infinite?
There was a question asking the electrostatic force between two charges if a a copper plate of thickness d/2 is kept between them. The effective force was 0. How?
0
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0answers
22 views
Describing the shape formed by crushing malleable cubes
I just watched a video of cubes of various metals being crushed by a hydraulic press (on the hydraulic press channel). Two of the cubes (made of somewhat stronger materials) deformed into an ...
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0answers
20 views
Hall coefficient for metals negative
I am wondering why the Hall coefficient for Al is negative, I am thinking about holes (I understand how holes word in semiconductors, but I can not use that because metals have no bandgap...), but I ...
1
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2answers
62 views
What makes seasoned cast iron non-stick?
I get how Teflon works, but am curious how the act of seasoning cast iron makes it non-stick. Does this also work for other metals besides cast iron?
1
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1answer
106 views
Temperature dependency of electron density in metals
I wanted to know how the electron density in metals behaves with temperature. I couldn't really find an answer online so I searched through my x-years old scripts and, surprisingly, I found a sentence ...
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0answers
34 views
Does the Mott metal-insulator transition occur with increasing or decreasing density of valence electrons?
When reading about the Mott metal-insulator transition, it has not become clear to me if the transition from a metal to an insulator occurs with increasing or decreasing density of valence electrons.
...
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1answer
63 views
Metal-insulator transition (material properties)
When studying about metal-insulator transitions, I was wondering which material properties can give direct information about this phenomena. Also, what information can be derived from these properties....
2
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1answer
87 views
Why free electrons do not leave the surface of metal?
In metals free electrons can move freely over the whole piece of metal, but they do not leave it. Moreover in electrified metals the extra electrons are located near the surface of the metal, but do ...
