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24 views

Metal density increase [on hold]

Can you increase the density of a metal by surface treatment? For example copper. Heating and quenching looks it doesn`t work well.
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0answers
38 views

Is Iron/Steel the best all round construction metal, or just the cheapest? [on hold]

Steels are incredibly versatile alloys based on Iron. Are there any other metallic elements that are similarly versatile? Obviously in the real world cost is a factor, but ignoring that, anything ...
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3answers
53 views

Is there a way to measure the thickness of a metallic plate of order of micrometers?

I have a $5 cm×5 cm×? \mu m$ copper plate. Where '$?$', the thickness of the plate, is really small (about 30um). Is there anyway using physics to calculate the thickness? Update: Sorry I forgot ...
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2answers
35 views

Why chromium is more brittle than iron at room temperature?

Why is chromium more brittle than iron? I understand that both of them are BCC at room temperature. Is it to do with the grain size, and why is it different between the two metals?
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0answers
8 views

How long is the surface migration length of adatoms deposited by thermal evaporation in vacuum?

The deposition of metals through thermal evaporation involves the process of adatoms migrating on the substrate before its kinetic energy decreases to a certain point or before encountering a cluster. ...
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1answer
39 views

Electric current in metal objects

This might be a stupid question, but I can't find the answer anywhere. Why don't objects such as rings that people wear (which are made out of metal) have electric current in them? As far as I know ...
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0answers
40 views

Why does thicker aluminum do better at reflecting wifi

I have performed a experiment based one the ability of aluminium reflecting wifi radio waves. I have found out that the more aluminium foil i put on my reflector, the better result I can get. I did up ...
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1answer
32 views

Is it possible to levitate large objects through diamagnetic levitation?

I am currently building a diamagnetic levitator with a strong neodymium magnet, two slabs of bismuth (a diamagnetic material), and a small neodymium cube to levitate. However, I was wondering if it ...
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1answer
92 views

What is the desest material on earth? [closed]

Apart from the elements, do we know of materials that are denser? I.e. can an alloy be denser than the sum of its compounds, for example if the new lattice packs denser than each of the compounds it's ...
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1answer
26 views

What determines photoelectric yield

Is there any difference between the photoelectric yield of different metals apart from the threshold wavelength? To be more clear: Will metals with the same work function emit the same amount of ...
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1answer
36 views

Photoelectric effect on charged plate

As far as I know, to observe the photoelectric effect, one has to expose a metal surface to high-energy radiation. But what happens if the surface has a surplus of electrons? What is the energy needed ...
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1answer
49 views

Is the photoelectric effect 'Ionising Radiation'?

According to the definition on Wikipedia, ionising radiation is radiation which has sufficient energy to remove an electron from an atom. So a high energy gamma ray is definitely ionising, but visible ...
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0answers
6 views

Hopping integral for Hydrogen chain

When calculating a hydrogen chain in the tight binding approx., one comes across the hopping integral: $<m+1|V_{m+1}|m>$ Where $|m>$ is the 1s-Wavefunction at position m and $V_m$ is the ...
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1answer
43 views

How to reduce size of bracelets using physics?

My mom has a set of bangles (bracelets) made of gold like the ones shown in the picture. Problem is the size (diameter) of these bangles is a bit more than required. If she goes to a goldsmith he cuts ...
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2answers
52 views

Why are metals worse conductors when heated?

When metals, (such as in circuits), are heated, their ability to conduct electric current is hampered. Why is this? Does the transition towards liquid disrupt a metal's ability to conduct, or is ...
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0answers
26 views

How can a metal and an insulator have high dielectrics yet one is conducting and one is insulating?

I don't get it: insulators are referred to as dielectrics. The higher the dielectric the higher the insulation(?). But the dielectric constant of metals is considered infinite. Aren't they supposed to ...
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1answer
60 views

What happens at the point of welding iron?

What is the physics behind welding iron? It is obviously the electricity that causes the two metal parts to fuse but what is the role of the welding rod and why is it said to damage your eyes when you ...
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0answers
9 views

Effective interaction between electron-magnon in ferromagnetic transition metals

I wonder whether there are classical references on an effective theory of electron-magnon interaction in itinerant ferromagnetic metals?
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1answer
34 views

When electrons absorb energy and get excited then jump to a higher energy level do they do so in steps or do it directly?

So I was reading about Fermi surfaces. One of the first things that is obvious is that energy excitations happen at the boundary of the surface as the electrons deeper inside the surface do not have ...
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1answer
27 views

Find the spectral distribution of a metallic reflection given electron configuration

If I have the electron configuration for a metallic element, how do I find the spectral distribution of its specular reflection? For example, for gold (2,8,18,32,18,1) I should get a greater ...
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1answer
48 views

How is work function related to oxidation?

Low work function metals, such as Li and K, oxidize in ambient conditions, whereas high work function metals such as Au do not oxidize. In chemistry there's activation energy and reaction rate ...
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1answer
27 views

Are all FCC structures ductile?

Doing research on crystal structures and the effects of Ductile to Brittle transition at different temperatures. Results of this test proved aluminium to be a brittle structure, which I know to be ...
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1answer
18 views

Estimating fraction of radiant energy absorbed by a metal

I have a couple of texts on thermodynamics and radiant energy but am finding it difficult to figure out from these how energy absorption and reflection work. The area of interest is heating ferrous ...
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2answers
76 views

How to attract liquid metal with magnets

I would like to know if there is any way that I could make mercury or another liquid metal be attracted or repelled by magnets. Absolutely any solution would be okay with me. For example... can I ...
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0answers
49 views

absorption spectrum of aluminum

I am trying to find the absorption spectrum of aluminum but only can find reflectivity of it and other optical properties. It is easy to find absorption of aluminum oxide, foams etc. but not possible ...
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0answers
63 views

Model of the nucleus as fermi gas

I am taking an introductory course in modern physics, and am reviewing some of the exams from previous years. In our course, we studies the Fermi gas model for electrons in a metal. In one of the ...
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1answer
52 views

Can a magnetic field weaken aluminum?

I'm wondering if there is any reason to suspect that applying a magnetic field to a piece of solid aluminum would weaken it structurally in any way. The application is that I would like to put a stir ...
3
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1answer
77 views

What happens to the electron density in a metal during an electric discharge?

Suppose we are able to see into a grain of metal at the boundary between the grain and air (perhaps along one of the faces of this cube): (Source: Wikimedia Commons.) This image does not show the ...
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0answers
170 views

Could a falling office tower cause the melting of its iron or steel support structure? [closed]

Discussion on META: Questions related to geopolitical events Suppose you have an office tower, weighing around 300,000 metric tons, and has a height of ...
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0answers
81 views

What is “Accumulated plastic strain rate” in Current yield Norton law?

I'm doing FEA of steel under high strain rates and using Elasto-ViscoPlastic material model, with Von-mises yield criterion along with Isotropic hardening. The strain rate sensitivity is addressed by ...
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0answers
19 views

Are magnets attracted to mu-metal?

Are magnets attracted to mu-metal? Be aware that when watching videos of mu-metal they may have metals that are attached to the mu-metal and are attacted to magnets. Please don't get them confused.
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1answer
57 views

Can a magnetic ball “diffract” around a metal object?

Consider a magnetic ball falling through a copper pipe. It falls slower than it would if it wasn't near any copper. We can use this to determine that the closer a magnetic ball is to copper, the ...
2
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0answers
42 views

What kind of cheap, available, magnetic metal could I use for my boardgame? [closed]

My question revolves around my need to snap plaster walls to plaster dungeon floors for a boardgame called Dungeons & Dragons. My intention is to glue and paint over metallic strips under the ...
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0answers
11 views

Is it posssible to numerically simulate a metal layer the same way as a semiconductor one

I need to simulate a schottky junction device. Unfortunately, the software for simulation (AFORS-HET) doesn't allow adding metal (I need to simulate aluminum contact) layers (but it allows to add ...
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2answers
35 views

Enhancing of EM waves through a materal or waveguide

I'm wondering whether there are materials for which an incident EM wave would behave as $\vec E(z,t)=\vec E_0 e^{\kappa z}e^{i(kz-\omega t)}$ where z describes how far from the surface the fields are ...
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1answer
12 views

Passive cathodic protection

Trying to understand what is happening when we need protect peace of Fe by placing on it more active metal (for example Zn) like ...
0
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1answer
113 views

Magnetization of soft iron and steel

I was reading and I saw that the steel becomes permanent magnet whereas iron becomes a temporary magnet after magnetization during magnetic induction. Why does soft iron make temporary magnets and ...
0
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1answer
95 views

crystal structure of metals

I am studying solid state physics and I'm a complete newbie in that sense. I know that semiconductors and group IV elements bond themselves in the FCC structure with covalent bonds which satiate the ...
2
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2answers
88 views

Do metals *really* conduct at zero temperature?

The questions is mostly in the title, but might expose another of my misunderstanding of the band structure of solids and how that leads to metals and insulators. If we have a solid, and the fermi ...
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2answers
117 views

Why doesn't dielectric materials have coloured reflections like conductors?

I'm a 3D artist trying to learn the basic (or perhaps even intermediate) level of physics of photorealistic rendering. But most artist and tutorials on the internet have little to no clue of the ...
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1answer
314 views

How quickly does a small piece of molten steel cool at room temperatures?

Say I have a $(\frac{1}{2}D)^2 \pi \times \ell = (.05)^2 \pi \times .03 \approx 0.000236 \ \text{mm}^3$ piece of molten steel freshly spewed out of a hot nozzle. Now assuming the nozzle moves away ...
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0answers
33 views

Why can we treat (most) metals classically at room temperature?

When we consider how light and metals interact with each other at room temperature, the Drude model, which is a classical theory, is usually and successfully used. My lecturer explained something ...
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2answers
82 views

What is a simple calculation to figure out how many watts needed to maintain a hot piece of tungsten?

The specific heat of tungsten is $.13 (\text{kJ /(kg K)})$. 1 cubic cm of tungsten is .0193 kg And the melting point of stainless steel is $1900 \deg \text{K}$ conservatively (giving it plenty of ...
2
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1answer
85 views

What determines the rate of vibration decay of a metal?

Suppose we have a tuning fork in a vacuum and strike it. Is there anything in the theory of metals that would predict that the tuning fork's vibration amplitude would decrease with time. Put another ...
2
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3answers
111 views

How to measure thickness of an ultra-thin metal layer?

I have a sample of a metal (aluminum/oxide) layer with a gradual thickness ranging from monolayer to 100nm. This layer is deposited on a transparent substrate, like glass. How can I measure this ...
0
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1answer
40 views

Does a crucible need to be fired in a kiln before use?

Say I made a crucible out of aluminum oxide primarily. Won't it be fired by normal use of it or do you have to pre-fire it? I understand they do that to get a consistent mass measurement. But does ...
2
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1answer
131 views

Why is communication lost in lifts?

Why is communication lost in lifts and cellars? For example, If I want to phone to someone, there is no signal communication in lift. Who may explain it?
2
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1answer
88 views

Why titanium “writes” on glass , meanwhile don't scratching it?

It is possible to "write" on a piece of glass with a bar of titanium without scratching the glass. I think the explanation is that molecular connections in glass are stronger than in titanium and ...
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1answer
69 views

Effect of frequency on magnitude of photo current

In a photoelectric experiment, if the frequency of incident light is slightly raised while holding intensity constant, I understand that the number of incident photons decreases. This in turn results ...
2
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1answer
317 views

How can metals absorb light?

We're told that semiconductors have a bandgap and photons of an energy greater than the bandgap can be absorbed, exciting electrons from the valence band to conduction band. This therefore defines ...