15

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 ...


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 $\...


10

You can't find primordial radium because it's half life is too small compared to earths age. Even the radium isotope with the longest half life, $\ce{^{226}Ra}$ has a half life of only 1600 years which is magnitudes smaller than the age of the earth, which is estimated to be around $4.54\times 10^9$ years[1]. This means that whatever radium we can find in ...


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

The factors that generate mineral concentrations are complex and often only partly known Introduction: geology is complicated The one thing we can be very certain about is is that the distribution of minerals in the earth's crust has very little to do with the primordial origins of the component elements (that is where they came from in the early solar ...


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

You may heat mixture of $\ce{MnO2}$ with charcoal to higher than $\pu{850 °C},$ in the absence of air. Manganese will be produced in the solid state by reduction of the oxide. But it is sensitive to air oxidation and easily reoxidized. So better use an excess of charcoal. In the industry, rough $\ce{MnO2}$ out of the mine is first reduced to $\ce{MnO}$ by $\...


5

Elastic deformation properties like stiffness (Young's Modulus) vary very little with alloying element concentration since we are only working on the pre-yield bond strength. A pure iron, a carbon steel and a high alloy steel will only vary by about 15% in stiffness. So elastic properties will, as you suggest, be fairly invariant under small changes in alloy ...


5

There are a few papers on Zinc-Platinum Systems (e.g., Ref.1 and 2, which are also sited in Ref.3), but most of them are in German. However, there were few useful data published by Johnson and Dillon in their Research and Development Report (Ref.4): $$ \bf{The \ structures \ of \ platinum-zinc \ intermetallic \ phases}\\ \begin{array}{l|l r r} \hline \text{...


4

The reaction $$\ce{Al2O3 + 3 Mg -> 3 MgO + 2 Al}$$ is slightly exothermic, with a $\Delta H = \pu{-130 kJ mol^-1}.$ It is also exoergic at all reasonable temperatures, as $\Delta S $ is very small $(\pu{-1.5 J mol^-1}).$ So, the reaction is in principle feasible. The trouble is that $\ce{Al2O3}$ and $\ce{Mg}$ are solid at room temperature. And the ...


4

The purpose of roasting a/o calcination is oxidation a/o decomposition of original ore to form metal oxides. It is desirable to keep the intermediate product solid to obtain porous product. This allows easy access for further reduction by carbon monoxide by coke or charcoal reduction process. If oxides were in form of a solidified melt, the reduction ...


3

The gangue is mainly made of clay, and clay is a mixture of aluminosilicates which are hydrophilic, because their structure is surrounded by $\ce{-O-H}$ bonds. $\ce{O-H}$ bonds can make hydrogen bond with water, so they are easily wet by waters. If minerals are crystallized and not surrounded by these same bonds, they are hydrophobic. It is the case for ...


3

American Society for Metals has many publications. Temperatures below ambient are no problem for any aluminum alloys. They are commonly used for natural gas separation liquefaction exchangers and piping down to −100 °C (guess at the temp.). In the T6 condition (hardened) room temperature yield is 31000 psi; at 300 °F the short term yield is 20000 psi; 6500 ...


3

As I understand your question, “the two” refers to Zinc Gluconate and Zinc Ascorbate. Zinc gluconate and zinc ascorbate are distinctly different compounds. They are both adducts of Zn with one Zn and two bidentate oxygen-based ligands of organic acids. Some basic information from PubChem for both zinc gluconate and zinc ascorbate is given below. Zinc ...


2

Let's subdivide the CO2 standard entropy change reversible process into 3 parts: Isothermal expansion of one mole of oxygen from 1 bar to the equilibrium partial pressure of oxygen in a reactor operating at equilibrium at a total pressure of 1 bar (a Van't Hoff equilibrium box) Injection of one mole of oxygen at its equilibrium partial pressure into the ...


2

Research notes in this ACS article Kinetics of Hydrogen Reduction of Manganese Dioxide that even heating $\ce{MnO2}$ in an atmosphere of hydrogen gas only results in $\ce{MnO}$. The source further notes that very high temperatures (some 1,600 K) are required for any appreciable formation of the metal. As such, a more facile approach, simply dissolve the ...


2

You need to define what an "operating temperature" is, for what application. An alloy that will work perfectly fine as a structural material for your kitchen oven will fall apart if used in aerospace applications. Your best bet is to find alloys used in similar applications and argue, by analouge, that these alloys will also work with your ...


2

Interstitial compounds are typically obtained when elements such as $\ce{H},$ $\ce{B},$ $\ce{C}$ and $\ce{N}$ are located within the interstitial sites of a metallic substructure. Nonetheless, the metallic substructure is not that of the pure metallic element in most cases. For example let's consider $\ce{Nb}.$ We can dissolve some amounts of $\ce{N}$ inside ...


2

First of all, let's be clear on the the formula for chalcopyrite. It is $\ce{CuFeS2}$. The other copper-iron sulfide ore is bornite, $\ce{Cu5FeS4}$. Now, let's talk about copper extraction. What is written in your question is not correct and I am quite sure that's not how copper is extracted. If you heat the ore (roast) in reverberatory furnaces, it happens ...


2

Chalcopyrite $(\ce{CuFeS2})$ is the most common copper bearing mineral on earth (Approximately 70% of the world’s copper reserves are contained in the mineral chalcopyrite), but also the most stable minerals because of its structural configuration, face-centered tetragonal lattice (Ref.1). At present, there are basically two main methods employed worldwide ...


2

As we discussed in the previous query Is there any evidence, any evidence at all, that nascent hydrogen actually exists?, the nascent terminology is still in use even in good ACS / RSC journals, which are pretty selective. However, science does not rest on authority; seeing the usage of nascent (gas) does not make it an absolute truth whoever is the author. ...


2

Fresenius' analytical scheme is also one possibility, although it is not as direct. More information can be found in Harvey's Analytical Chemistry 2.1 Libretext. I bring this up to highlight that even though this is a classical technique, it is still mentioned in some analytical textbooks still in active use.


2

Your equation is the sum of two different and independent equations, namely $$\ce{2 PbS + 3 O2 -> 2 PbO + 2 SO2}$$ $$\ce{PbS + 2 O2 -> PbSO4}$$ And these equations are no use for producing metallic lead. They are not a moderate oxydation, as the ratio $\ce{O2/PbS = 5/3}$. Producing metallic lead by moderate oxydation requires a reaction based on the ...


1

There are several Inconels , the basic one is 600. Because the Inco and Huntington divisions are now gone or acquired ,it would be difficult to get literature . But they produced copious amounts , you may be able to find some ; I have about a 6" stack of brochures I have been too lazy to discard. American Society for Metals Handbooks should be easy to ...


1

Chemical Book reports that barium sulfate (barite, or baryte) is slightly soluble in concentrated sulfuric acid and soluble in carbonate alkali metal solution in which it is converted to barium carbonate; it is insoluble in other kinds of acid or base. It sounds like the barite is your culprit. If you try grinding it with an eye towards physically ...


1

The key point to remember here is that any metal that is oxidized more readily than copper will be reduced less readily. So yes, it will be oxidized before the copper in the impure sample, but it will not be reduced and deposited on the pure metal electrode. It will simply stay in solution as an ion as long as the process is stopped before all of the copper ...


1

According to the CRC Handbook of Chemistry and Physics, melting point of $\ce{CaF2}$ is $\pu{1418 ^\circ C}$, of $\ce{Al2O3}$ (in its corundum form) is $\pu{2053 ^\circ C}$, and of $\ce{Na3AlF6}$ is $\pu{1009 ^\circ C}$ (lowest of the all three). Thus the cryolite should melt first. I have read mentions of the problem you asked in the book Nonaqueous ...


1

Under sufficiently high pressure ammonium, $\ce{NH4}$, could form a metal. Such a metallic species may be present in the interiors of Uranus and Neptune [1](https://doi.org/10.1093/mnras/114.2.172). Reference 1. M.F.M. Bernal, H.S.W Massey, "Metallic Ammonium", Monthly Notices of the Royal Astronomical Society V114(2) (April 1954), Pages 172–179; ...


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