Hot answers tagged

56

There are many types of magnetic properties, including ferromagnetism, paramagnetism, diamagnetism, antiferromagnetism, ferrimagnetism, superparamagnetism, metamagnetism, spin glasses, and helimagnetism. Many of these are too weak to cause any noticeable interaction with a magnet. The type of everyday magnetism you're thinking of, which nickel has, is ...


25

None of the US coins are magnetic (ferromagnetic), except for the 1943 Lincoln penny (Steel Cents, made in steel and zinc to save copper for ammunition during wartime), which are considered magnetic. Almost all of those coins other than Steel Cents are made with higher percentage of copper ($\ce{Cu}$) and lower percentages of other metals such as nickel ($\...


19

The go-to place for alloy information is ASM International's Alloy Phase Diagram Database (providing your institution has access). Scandium-Gold: as noted in the comment by @MaxW, you can get several atomic percent (but less than 10 at.%) Sc in Au. There exist 6 compounds across the diagram which you would want to avoid most likely. Scandium-Platinum: ...


17

Metals have several general properties in common (to some degree): Luster - metals are shiny Electrical conductivity - metals conduct electricity Thermal conductivity - metals conduct heat Ductility - metals can be drawn into wires Malleability - metals can be beaten into shapes Fusibility - metals can be melted and forged All of these properties derive ...


14

AlMg3 is not the chemical formula of the alloy, it's the product name for a wrought alloy. Its technical sheet specifies the following composition: Product name AlMg3 Class of product Al-Mg alloy for MIG/TIG welding. Corresponding standards DIN 1732, SG-AlMg3, AWS A5.10, ER 5754 Nominal composition (weight %) Al: Bal. Si: 0.4 Mg: 3 Mn: 0.5 Thus, the 3 in ...


14

Similar to inox for inoxydable (inoxidable), it equally is a French coinage. To tune mechanical properties of iron, mixing additives leads to numerous alloys of iron. In case of rene or rené as contraction of résistant (durable) and on base of Nickel, and is example of the superalloys. This source technologie des métaux et alliages - particulièrement en ...


14

First, the alloy $(0.5$ to $\pu{2 g})$ should be treated by $\pu{10 mL}$ nitric acid $32\,\%.$ All metals will get dissolved, except tin and silicon, which will be transformed into insoluble dioxide $\ce{SnO2}$ or $\ce{SiO2}$. Dilute in $\pu{100 mL}$ hot water. $\ce{SiO2 + SnO2}$ will make a gelatinous precipitate, that can be eliminated by filtration. Add $\...


13

One of the key considerations is that much of the interesting mechanical behaviour doesn't occur within the bulk of the material - it occurs at the interfaces between crystals (known as grains). Grain boundary slip, rotation and growth often defines the mechanics - carbon has a tendency to block the motion of grain boundaries, which are one of the key ...


12

You are labouring under a misconception about the exact meaning of the word "compound". Normally when we describe, for example, ethanol as a compound of hydrogen, oxygen and carbon we don't mean that the component elements can "leak" out of it without a chemical reaction taking place. Mercury amalgams are casually described as "compounds" but not in the ...


11

Virtually every analytical chemistry textbook's chapter on anion determination mentions that Devarda's alloy is very brittle and can be easily pulverized in a mortar, unlike $\ce{Al}$ and $\ce{Zn}$ metals. This is quite handy property as for qualitative analysis of nitrates in a heterogeneous media the reducing phase should be ground to fine powder in order ...


11

You seem to approach the separation of alloys much like the separation of water-soluble salts, probably based on the fact that both involve the liquid/solid phase diagrams, which may even look alike. This is wrong; these systems are fundamentally different. Say, you have a water solution of some well-soluble salt which you need to recrystallize. You cool it ...


10

Sure. Even discounting non-equilibrium conditions, any substance which expands upon freezing will by symmetry melt under pressure, even if the pressure is caused by supporting its own weight. There's a simple example: water! A sufficiently tall self-supporting block of ice standing on a flat surface will create enough pressure at its bottom that it could ...


10

You can combine materials in two ways: chemically and mechanically. On average, if you want to the desired physical properties to add up, you want to go mechanical way, not the chemical one. Once the reaction takes place, the there is absolutely no reason to assume the product preserves properties of both precursors. It might sometimes, but more often than ...


10

Bottom line: there are no simple rules of thumb. To demonstrate this, I will show a round robin of phase diagrams for fcc metals ($\ce{Ag}$, $\ce{Cu}$, $\ce{Au}$, $\ce{Ni}$) with no intermetallic compounds - just fcc solid and liquid. $\ce{Ag}$-$\ce{Au}$, full mutual solubility, liquid and solid enthalpies of mixing pretty close: $\ce{Ag}$-$\ce{Cu}$, with ...


9

Let's consider that steel may contain $\pu{1\%}$ carbon. I know it is a bit much. Let us express this mass concentration as molar concentration for a sample of $\pu{100 g}$ of steel. Since this sample contains $\pu{99 g}$ of iron, this amount equates to $$n(\ce{Fe}) = \frac{\pu{99 g}} { \pu{56 g mol^{-1}} } = \pu{1.768 mol}$$ and $$n(\ce{C}) = \frac{\pu{1 g}...


8

Here you can find a phase diagram for $\ce{Si/C}$ system. It does not have zones with homogeneous non-stohiometric solids. So, there is not thermodinamically stable Si/C isomorphic alloys. However, since the liquid likely to be homogeneous, it is likely for fast cooled liquid to form amorphous alloys. Indeed, google search provides plenty of links for ...


8

George Lai's High-Temperature Corrosion and Materials Applications (excerpts available on Google Books) is a good source. Very often for molten salts, Hastelloys are used; they're special-purpose alloys developed by Haynes International. I can't find a reference, but I believe Oak Ridge National Laboratories used Hastelloys for their molten salt reactors (...


7

Iron does not form an amalgam readily, hence the use of iron electrodes in mercury switches. Apparently, iron does form alloys with mercury under specific conditions; see http://www.madsci.org/posts/archives/2011-04/1304143502.Ch.r.html. By contrast, mercury spilled on gold (e.g. gold-alloy jewelry) soaks in immediately, discoloring the gold, and migrates ...


7

An alloy is purely a mixture of metals (and sometimes non-metals) which are non-chemically bonded. So yes, you could mix steel and silver to create an alloy. There would be nothing stopping you from doing this, but I cannot say whether or not it would produce any desirable results. Mixing alloys with other materials is merely creating another alloy. ...


7

Much of this answer is based on a document available from NIST at Properties of Ternary Copper-Silver Systems [originally J. Phys. Chem. Ref. Data, 6(3) 621-673 (1977)] - this has an equivalent to the diagram in the question (which is just the surface of the liquidus). Now, since you are talking about balances of solid phases, it is also worth looking at the ...


7

Current IUPAC recommendations suggest following electronegativity ordering. The symbol for iron (a less electronegative element among the two) should be written first: $\ce{FeCo}.$ From the section IR-4.4 Sequence of citation of symbols in formulae [1, pp. 58–59]: IR-4.4.2 Ordering principles IR-4.4.2.1 Electronegativity If electronegativity is taken as the ...


7

Possibly, there are two extrema to account: a) the atomic radii of metal A and metal B do not differ significantly, and thus there are chances both metals blend statistically with each other. Which would be covered by the $< 15\%$-rule, a situation similar to mixing apples and oranges in one crate. b) the atomic radii differ a lot. If we assume atoms as ...


6

In case your mercury didn't come with an assay of the supplier, or has been used before, you might want to remove oxidizable metals by repeatedly dripping the mercury though diluted nitric acid and distilled water. Subsequent distillation of mercury is certainly possible (at 25 mm Hg or lower), and has been reported by E. H. Riesenfeld and W. Haase in Ber. ...


6

Silly answer There is no enzyme that grinds down an Airstream, but an alligator might do the job! Serious (but disappointing) answer In nature, most metals seem to exist as oxides, sulfides, carbonates, halides, etc. and not as bare metals. Consequently, there was/is probably little evolutionary benefit in tackling the bare metals. Breaking down ...


6

When alloys are made by mixing molten metals (actually an alloy only need contain one metal and at least one other compound, metal or not) the metals only need to be heated to their melting point, not all the way to their boiling point. In the example you've given, the melting point of aluminum is $\pu{660^oC}$, which is $\pu{247^oC}$ below the boiling point ...


6

It provides limited corrosion protection. I would suggest just putting oil on it; more corrosion protection and it will not obscure the surface pattern which is most all that separates Damascus steel from ordinary steels. As I remember regular "bluing" is a complex of ferocyanides ; Oxides of iron are red and black , brown rusts are hydrated oxides. I have ...


6

The melting point of the vast majority of materials increases as more pressure is applied. At https://www.researchgate.net/figure/312054885_fig1_Figure-231-Experimental-pressure-temperature-phase-diagram-of-pure-iron-a is a phase diagram showing how this variation occurs for pure iron: From https://physics.stackexchange.com/questions/184032/what-is-the-...


5

For any steel with less than 0.02% carbon we should see only ferrite, and for steel with >0.02% carbon we should see only pearlite. You have got a small misunderstanding here. The maximum solubility of carbon at $723\ \mathrm{^\circ C}$ is 0.02%. At room temperature it is very low ($0.005%$ at $0\ \mathrm{^\circ C}$). Also for carbon level between 0.02 and ...


5

'Leak' is an imprecise term here. Amalgam itself could (and probably does) wear away with attrition, and the 'powder' would be ingested. Certainly, fillings have worked loose and been swallowed. The effect of stomach acid on amalgam is probably not negligible.


5

I have a solid steel pint glass and I can tell you that it pretty much instantly heats up to the temperature of the liquid you put inside. You probably have some sort of double-wall vacuum flask, which insulates by using a vacuum between the steel. As you can see, there are two walls to the flask: an inner wall and an outer wall. The inner wall is probably ...


Only top voted, non community-wiki answers of a minimum length are eligible