Questions tagged [metallurgy]

Chemical and physical characteristics of metals and alloys.

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10
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2answers
6k views

When is Serpeck's process preferred over Bayer's process?

Both these processes are used in concentration of bauxite. They use different reagents. Which is more commonly used (wikipedia says Bayer's) and why? When is one preferred over the other? Which is ...
15
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3answers
5k views

How does chromium help stainless steel prevent rusting?

Various sources (such as this one) say that stainless steel is stainless because a passivation layer of an oxide is formed, but I haven't found details on why chromium helps create this passivation ...
10
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2answers
21k views

What is the difference between tempering and hardening metals and their end products?

I think I've heard hardening is when you dunk red-hot metal into cold water, and tempering is when you take that hardened metal, heat it slightly, and then let it cool slowly. However what is the ...
7
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1answer
3k views

Does Gallium (liquid or solid) corrode all forms of brass?

I know that it corrodes copper, but does it do the same to all brass or bronze compositions?
7
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1answer
840 views

Why doesn't the Bessemer process oxidize the iron?

The Bessemer process for making steel involves blowing air or oxygen thru hot iron. Impurities and carbon oxidize away. Why does the iron itself not oxidize?
5
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2answers
3k views

Having trouble understanding the iron-carbon phase diagram

At room temperature, alpha and alpha+$\ce{Fe3C}$ are present (depending on carbon content), which is ferrite and pearlite. In the lab we polished and etched samples of carbon steel to observe the ...
4
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1answer
95 views

Separating metals out of a magnet

I have acquired the crushed magnet out of a motor I was given. If I'm correct that the magnet is $\ce{NdFeB}$ magnet, how could I separate out all the metals into a pure or oxide form? And for hard ...
-2
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1answer
112 views

Trying to figure out what these elements have in common [closed]

I have an old periodic table and I marked five metals from groups 1A and 2A with dots to indicate something about them. Only all this time later I can't figure out what exactly it was. I've been ...
3
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2answers
597 views

Calcination in metallurgical process?

In calcination why is the ore heated in the absence of air in a reverberatory furnace, does the presence of oxygen affect any thing?
6
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2answers
879 views

Can powdered beta-tin be made from raising the temperature of alpha-tin?

When white tin ($\beta$-tin) is cooled to a temperature below $13.2\ \mathrm{^\circ C}$, it creates the allotrope of gray ($\alpha$-tin), a gray, amorphous powder. My question is that once you have ...
4
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1answer
119 views

What safety measures should I take when operating a backyard aluminum furnace

I have made a DIY furnaces out of cement. Before I do any smelting, I would just like to take any suggestions in regards to any safety measures I should take. I plan to only melt aluminum cans and ...
2
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1answer
999 views

Can alloys or ceramics have higher density than elemental solids?

Are there any examples of alloys or ceramics that have higher density than their densest elemental constituent? If so, do they have unusual or difficult synthesis processes? If not, is it provable ...
0
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1answer
26 views

Replacement For RF sputtering

In my experimental work, I'm following an article. It said that: A 30 nm ZnO seed layer was deposited on the glass substrates by RF sputtering of a ZnO target at room temperature. But I haven't ...
2
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1answer
1k views

Cathodic protection of tubes in Shell & Tube Heat Exchanger

Our $\ce{Cl2}$ liquifier is of the following type: It is entirely made of mild steel (shell as well as tubes plus the connecting pipelines). At shell side there is Freon (R-12) with its refrigeration ...
3
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2answers
339 views

Good choice for heat-conductive coil submerged in sea water

I know only as much about chemistry as I can remember from a year in college. So, please speak slowly and use short words. I'm trying to decide on an appropriate material for a heat-transfer coil ...
2
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0answers
181 views

Two 2" solid steel bearings for stress relief hand-rolling. Safe? What's that smell? How to thoroughly clean?

I bought these two 2" solid steel ball bearings for the purpose of rolling them in my hands. Just for something to do while sitting at my computer, without those silly bells inside. (They're still a ...
2
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1answer
1k views

Is there a material that reduces copper melting point and completely dissolves?

Is there any material that you mix/alloy with copper that will result in something that behaves similar to plastic (that is at room temperature it is solid, at maybe 500K or similar it can be easily ...
17
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4answers
1k views

What possibilities are there for refining aluminium on the moon?

Engines burning aluminium and liquid oxygen have been investigated for use on the moon because there is plenty of both elements in the soil - about 13% and 40% of highland soil, respectively. ...
4
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1answer
611 views

Are there carbon-silicon alloys?

Both carbon and silicon expose a lot of metallic properties like metallic lustre, electrical and heat conductivity, etc, so often considered metalloids. The both form alloys with other metals such as ...
3
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1answer
2k views

How will liquid nitrogen affect a steel instrument's ability to function?

I want to retrieve cryotubes from the bottom of a liquid nitrogen freezer without taking all the freezer racks out and draining the liquid nitrogen. I think I can accomplish this using a tool like ...
1
vote
2answers
546 views

Dissolving silver braze from tungsten carbide

I'm working out the best process to chemically strip silver brazing from tungsten carbide (WC) bits. My main objective is to recover the silver as a relatively pure metal. When I use $\ce{HNO3}$ at ...
1
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0answers
83 views

Is it dangerous to live near lead? [duplicate]

Several month ago, I soundproofed the door of my room with two sheets of lead. Can it be dangerous to live with them for many years? Can lead "decay" in some way and be inhaled? (and what happen when ...
2
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2answers
3k views

How to temper a non-ferrous metal

Can non-ferrous metals/alloys (copper, brass, bronze) be tempered (made harder) by temperature control alone, like ferrous metals? I understand it's simple to anneal copper, brass, etc., just by ...
7
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1answer
227 views

Contactless non-ferrous metals hardening?

Is it possible to work-harden non-ferrous metals without direct contact? I know induction hardening is used on ferrous metals, but would like to know if a technique exists for non-ferrous metals.
3
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2answers
540 views

Material that doesn't melt at 800 deg F, but can be dissolved?

I'm a sculptor and I have a chemistry/plastic question. I thought here would be a good place to ask. I'm looking for a substance (probably a plastic) that has these characteristics: Doesn't melt at ...
2
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0answers
336 views

Are forming coins starting with sodium chloride possible without the clay melting from the molten metal?

Is forming metal coins (specifically ones with copper, nickel, and zinc) possible with these steps: Carve a sheet of sodium chloride so that it is big but not too big and so that the design sticks ...
0
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1answer
2k views

What are the properties of alloys? [closed]

You spend a lot of time in chemistry talking about molecular amd ionic compounds, but I'm interested in what you can do with metals only. What is the difference between the properties (physical & ...
2
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1answer
655 views

How is ammonia used in production or processing of steel?

There are some large tanks of ammonia in nearby iron works. I wonder, what do they need it for? What is the application of ammonia in steel industry - what processes of making or processing steel ...
1
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1answer
109 views

How can I determine/quantify the presence of boron nitride on a metal surface?

We use micron-grade hexagonal boron nitride (hBN) to coat the surface of bullets that are jacketed in gilding metal. This coating is mechanically embedded/plated onto the surface in order to increase ...
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4answers
604 views

Percentage of carbon in stainless steel to avoid brittleness

What is the maximum percentage of carbon allowed in stainless steel 202 so that it does not cause brittleness?
2
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1answer
70 views

What type of material is this and how is it corroding?

So I was thinking about corrosion and I came across this structure(see image) Do you think the inner metal/alloy that is corroding is steel? Also, what do you think the outer layer (in white) is? ...
3
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2answers
2k views

can an alloy be used to make another alloy?

The answer is likely very obvious but I know pretty much nothing about this so: Can I make an alloy, using an alloy? That is, could I make an alloy of steel (in itself an alloy of iron and carbon) ...
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2answers
3k views

Why does gold react with cyanide and sodium hydroxide

Why does gold react with cyanide and sodium hydroxide and what is the chemical reaction's impact on gold's atomic structure and bonding? What I think is since in the 'flotation' process, when the ...
1
vote
1answer
201 views

Rapidly cooling Aluminum vapour to solid state?

What sort of a microstructure would you get on bubbling Aluminium vapors through a large tank of Helium?Would it be a glassy microstructure and/or would you get nano-powders? and/or a new crystal ...
3
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1answer
10k views

Calculating percentages of microstructures in equilibrium phase diagrams (engineering)

So I have an equilibrium phase diagram of steel and I am asked to 'Calculate the proportion of pearlite in the microstructure of 0.4 wt% C steel just below the eutectoid temperature (727 °C).' I have ...
3
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1answer
117 views

How do I start studying chemical nomenclature?

Chemical nomenclature seems to be the way chemistry "talks", allied with the mathemathics. But where to start?... and what reasons and theories are behind? Some "names" come from latin... I know there ...
4
votes
5answers
33k views

Which has more metallic character: aluminium or magnesium?

Which element has more metallic character - aluminium or magnesium? I know that metallic character decreases along a period (from left to right) and increases down a group. Aluminium comes after ...
9
votes
1answer
2k views

Extraction of Sn from SnO2

In the extraction of $\ce{Sn}$ from $\ce{SnO2}$ by carbon reduction method, why is $\ce{CO}$ formed instead of $\ce{CO2}$ as per the following reaction? $\ce{SnO2 + C -> Sn + CO}$
4
votes
1answer
3k views

Why is AlMg3 called aluminum alloy?

In AlMg3, magnesium atoms outnumber aluminum atoms by a factor of three. In terms of mass, the ratio of aluminium to magnesium is a mere $27.0 / (3\times24.3) = 0.37$. Shouldn't AlMg3 be better ...
3
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2answers
771 views

How to remove Sn from Sn60Cu40 alloy?

I have practical question. How can I chemically remove $\ce{Sn}$ from $\ce{Sn60Cu40}$ alloy? I want to get something like copper sponge this way. Something like nanoporous gold produced from $\ce{...
8
votes
1answer
5k views

Why is it hard to reduce titanium dioxide?

Titanium is expensive, although it is not rare and titanium dioxide is a ubiquitous component, it's part of such mundane articles as toothpaste, paper or plastics. The reason for that is that the ...

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