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Questions tagged [metals]

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2 votes
1 answer
62 views

Why defects don't have an effective charge in metals?

In semiconductors and insulators, crystal defects, e.g., vacancies and interstitials, are treated as having an effective charge. In metals, however, defects are treated as neutral. I can expect that ...
6 votes
1 answer
687 views

What's the transition from "metal" to "electron-degenerate matter" look like?

Question: Say that we had metallic water and compressed it until it qualitatively resembled the state of matter in a white dwarf: what would that transition look like? Background (revised to be ...
4 votes
2 answers
639 views

Size of the Fermi surface of hole and electrons

The image below shows the shape of a Fermi surface of Cr metal measured by Angle resolved photoemission spectroscopy. (not important) The question is why does the Fermi surface shrink for the ...
-4 votes
2 answers
175 views

Can metal get hotter than heat source? [closed]

Trying to understand something I have actually witnessed.. My cousin is a welder, and claims that a 400 degree acetylene flame will in time melt steel. He showed me a 400 degree flame, then had a ...
1 vote
1 answer
261 views

Magnetic static field simulation software to model metals in Earth's magnetic field

I need to model the effect of steel or iron objects of a given shape disturbing Earth's magnetic field like shown in the pic below. The software, providing a solution, should be free and open source. ...
0 votes
3 answers
201 views

Does heating a jar lid significantly expand the metal?

The heat from hot water expands the air inside the jar relieving the amount of negative pressure inside the jar. Hot water may additionally help to loosen any sticky material inside the jar lid from ...
1 vote
0 answers
22 views

Surface plasmon polariton filling the gaps

Why does the angle of incidence on a DPS(positive electric permeabillity and magnetic susceptibillity)material and a SNG(1 of $\epsilon$ and $\mu$ positive)material have to be close to 90 degrees to ...
0 votes
1 answer
62 views

Doubt regarding time lag during photoelectric effect

Recently,I was reading about the photoelectric effect and have a doubt regarding it: Suppose I irradiate a metal surface with a monochromatic beam of light of frequency 'μ' such that μ > μ0 where ...
2 votes
1 answer
2k views

How is spring steel so hard?

The mechanical properties of a steel object are influenced by the metal composition, the manufacturing process, and the final heat treatment of the object. Spring steel is a steel that was heat ...
0 votes
1 answer
699 views

How is an Eddy current separator actually getting the particle fly off?

I am currently trying to understand the eddy current separator on a physical level, but unfortunately I have a few uncertainties to resolve. I don't quite understand what is ultimately the reason why ...
2 votes
1 answer
36 views

Why don't the delocalised electrons in a metal emit light when they hit an atom and change their velocity very quickly (i.e. accelerate)

We know that in metals there is a sea of delocalised electrons which can freely travel around the lattice of metal ions and that these delocalised electrons move around at large speeds, sometimes ...
0 votes
0 answers
19 views

What causes bands to shift in energy or become narrow?

This is the density of states for pure palladium in bulk : This is the density of states of palladium hydride : clearly the d bands are shifting and becoming narrow. The narrowing of bands is said ...
0 votes
0 answers
37 views

What happens after bulk gold absorbs a photon with its energy at the band gap or higher (wavelength < 500 nm)?

As is explained in the answers of this question: Why are most metals gray/silver? nicely, the responsible transition occurs between the 5d orbital and the 6s orbital, which is relativistically shrunk ...
2 votes
1 answer
91 views

Relationship between Density of States and the Fermi level

My understanding is that given the DOS of a material we find the fermi level by filling electrons into those energy levels and when we run out of electrons we reach close to the fermi level (or ...
0 votes
1 answer
841 views

Fermi Gas - Number of Free Electrons at High Temperatures

What I am trying to do is to compute the specific heat of a free electron gas in a conducting metal. I am using Fermi-Dirac statistics as my framework to build off of. Importantly though, I want to ...
1 vote
2 answers
1k views

Is rust a good thermal insulator as opposed to bare steel or hardened clay?

I have no idea, if this is the correct site to find an answer on this topic, but considering it's a question of physical interactions I wanna give it a shot. I am in no way a physicist, just a ...
9 votes
1 answer
376 views

Can any element be a metal?

I was reading that hydrogen can become a metal in some cases, like in Jupiter, and the same for helium. Is this true for all non-metals?
0 votes
2 answers
65 views

Why don't all metals have closed pack structures?

A lot of times, in my materials classes, metal atoms' behavior during deformation is described like a bunch of stacked balls. In my introduction to material class, our professors explained that metals ...
0 votes
1 answer
48 views

Cross Section Area

When bending sheet metal in a press brake, it stretches slightly. For example, if I had a piece of steel 200 mm long by 1 mm thick and bent it in half, the two legs will each be longer than 100 mm so ...
0 votes
0 answers
6 views

Ultra-strong nanocrystalline metal without transition to superplasticity

It is known that a decrease in the grain size of a polycrystalline metal to 1 micron is accompanied by an increase in its strength by several orders of magnitude (super-strength) almost to the ...
1 vote
2 answers
85 views

Did my pot really reach >400°C internally while heating water (soup broth)

I have a 1800W induction cooktop. In my experiment, did the following steps: I placed a stainless pot on the cooktop, half filled with fridge cold chicken broth. I heated the pot at 1000W until I ...
0 votes
0 answers
16 views

Which properties of a metal can be measured via an Inductor in an $RLC$ circuit?

I am trying to understand the properties of metals by using them as cores for an inductor in an $RLC$ circuit. Now the resistivity, saturation point, magnetic permeability electric permittivity all ...
3 votes
2 answers
2k views

Does the photoelectric effect heat the metal and exert a force on it? How?

The photoelectric effect says that the energy of a photon, if greater than the work function of a metal will liberate an electron from it. The additional energy of an electron just gets converted into ...
0 votes
0 answers
18 views

Changing element and isotope ratio ratio in material in space

Suppose we have a satellite orbiting Earth with a component made of 6061 aluminium alloy. Would cosmic radiation cause the element and isotope ratio of the component to change in a clearly measurable ...
0 votes
1 answer
119 views

Fresnel Equations, Refraction, and Metals

I'm trying to make sense of how the fresnel equations apply to metals. Here are a few of the things I believe I understand: All reflections of light occur specularly. When an object appears to ...
1 vote
0 answers
31 views

Fresnel Equations and an Opaque Surface?

I'm trying to make sense of what actually happens to light when it interacts with an opaque surface. The fresnel equations give us the proportion of light which is reflected off the surface of a ...
0 votes
0 answers
23 views

Vibrating object on optical table

Wikipedia says this about optical tables: Many optical systems require that vibration of optical elements be kept small. As a result, optical tables are typically very heavy and incorporate vibration ...
3 votes
1 answer
79 views

Is metallic hydrogen solid or liquid?

If I squeeze hydrogen superhard with 400-500GPa of pressure, it becomes metal so is that solid or liquid? I know gallium melts on my hand and it's metal.
1 vote
1 answer
219 views

Is it possible for aluminium alloys in an explosion to become pure elemental powder particles?

I am making a paper about metals and would like some help with this issue. If you have some kind of explosion, is it then possible for aluminium alloys to become powder particles?, if yes, can they ...
0 votes
1 answer
88 views

Why/how is this crumpled wad of aluminum foil exhibiting strong magnetic repulsion against everything?

Forgive the extreme, potentially unnecessary, detail, but I'm trying to include all possible info to account for all possibilities, as this has driven me mad here. I lined a baking pan with Great ...
0 votes
0 answers
111 views

Richards rule melting enthalpy

I know that Richard's rule states that entropy of fusion is constant for metals, and that it is ~2.2 cal K-1 mol -1. I am struggling to find the origin of this statement, is it empirical? What is its ...
1 vote
1 answer
74 views

Why and How Moly (Molybdenum) can melt at 800°C inside muffle furnace?

I kept a ceramic cylinder wrapped in a Moly sheet. This whole thing was kept on an another Moly sheet inside muffle furnace. I ramped up the muffle furnace to 800°C in half an hour, kept there for ...
3 votes
1 answer
58 views

Would a vibrating metallic and charged surface emit electrons?

Consider a metallic object under an intense electric field so its electrically charged in its surface. If the object is set to vibrate could it emit electrons? Maybe if the frequency is high enough? ...
3 votes
2 answers
1k views

Will an extremely hard material wear away or fatigue if enough very-low energy contacts occur with a softer material?

So let's say that I have a tool that's made of a very tough and hard material, like tungsten carbide or some kind of gem stone. My understanding is, there are limits to every material, that up until ...
1 vote
0 answers
17 views

Extremely strong peak around 10 eV energy of Aluminum crystal in an x-ray inelastic scattering experiment

I conducted an experiment where I measured Bragg reflection for two different atomic planes (200 and 400) of Aluminum crystal at an energy of 10 KeV. Then, in each of these two measurements I shifted ...
1 vote
0 answers
41 views

Does electric charge have any effect on diamagnetism?

Diamagnetic materials repel magnetic fields because freely moving electrons or cooper pairs within the material can form eddy currents in response to a changing magnetic field. It is natural to wonder ...
6 votes
2 answers
465 views

Is there a way to inspect thin metal weld (2 mm - 3mm) by ultrasonic testing?

I am working with an ultrasonic device to inspect welds. So far, I have learned that the minimum thickness of the metal sheet for this inspection is 6mm - 8mm. But the product of mine has 3mm thick ...
1 vote
1 answer
56 views

Do mirrors (with metal surfaces) show TIR (Total Internal Reflection)?

[Not a duplicate! Also, the answer to a similar question was unsatisfactory] I was digging into why we don't use mirrors in place of fibre optics cables. Majorly, the answers were as follows: It's ...
11 votes
3 answers
2k views

Why does Platinum evaporate if left long enough?

I have been reading into research relating to the redefining the 1 kg weight as the current Platinum-Iridium is becoming smaller. In this article, here, it mentions that the original metal weight ...
0 votes
2 answers
110 views

Can someone tell me why there are two values for the dielectric constant from this website?

I have been looking up at available database that had dielectric constants for metals since I need them for my research and wanted to get an idea of what the values were before I focus on actually ...
3 votes
1 answer
375 views

Absolute Seebeck coefficient of metals

Note: In literature, the Seebeck coefficient is most often given to platinum as a reference point, because it is challenging to measure the absolute Seebeck coefficient. It is however possible, this ...
1 vote
1 answer
47 views

Calculate Force Needed to Squeeze a set of prongs together? [closed]

I have an anodizing rack that has hundreds of prongs. These prongs are made of titanium and need to be squeezed together in order to place the parts on the rack. I am wondering how I would calculate ...
1 vote
2 answers
2k views

Is there a way to make infrared pass through metals?

I am curious to know a way that will make infrared pass through metals. Metals are good reflectors of infrared,can we manipulate the wave in order to make them pass through metals?.
0 votes
2 answers
40 views

How strength of RF coupling depend on the antenna material?

If we place different materials in the microwave owen, they will get hot at different speeds. For instance meals get hot really fast. What material property decides on the strength of the coupling? ...
0 votes
0 answers
29 views

Structural notation for multi-element FCC crystal structures

I was wondering if different compound FCC structures share any kind of indicator or structural notation which I could use to find and categorise them. To clarify my problem: the FCC L12 structure, ...
0 votes
0 answers
44 views

Question about the elasticity matrix in metals

The most general anisotropic linear elastic material has 21 elastic constants. I am working with an HCP material and I found that it has 5 independent elastic constants. I am programming a subroutine ...
1 vote
1 answer
256 views

Relation between Fermi surface and Fermi velocity

Is there a direct relation between the Fermi velocity and the Fermi surface? Can one reconstruct the Fermi surface if the full angular distribution of the Fermi velocity is known?
1 vote
1 answer
58 views

Is heat treatment the only means known to man for increasing grain size in steel?

It is well known that steel grains tend to grow larger under heat treatment. Is it possible to enlarge grain size through any other means? I cannot seem to find anything via web search. If steel is ...
1 vote
1 answer
92 views

Metallic behaviour explained by Nearly free electron model

I am having trouble understanding what causes metallic behaviour in context of Nearly free electron model. Is it because 1) In 2d material with fermi level equation is $k_F=\frac{√2πz}{a}$. If for a ...
6 votes
2 answers
10k views

Could airport security possibly distinguish gold and silver coins from other coins?

People usually don't carry pure gold and silver coins in their wallets. If I put some in my wallet, would it be likely that airport security would detect some anomaly with my wallet as compared to ...

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