All Questions
Tagged with material-science physical-chemistry
66
questions
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75
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Why does a mixture of bulk $\rm Hg$ + $\rm Cd$ +$\rm Te$ melt at a much lower melting point than any of its constituents?
In a real life setup, a mixture of $\rm Hg$, $\rm Cd$, and $\rm Te$ melts at approximately 330 degrees Celsius. The element with the lowest melting point is Te which melts at 449.5 degrees Celsius. ...
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0
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43
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How do relativistic effects lead to gold not usually occuring in a 2+ oxidation state?
In the literature I found compounds where gold occurs in a 1+ and 3+ oxidation state, like the perovskite CsAuCl_3, and also came across the fact that gold usually doesn't occur in a Au2+ state. ...
- 147
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24
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Are there any indications that the hat polykite or spectre appear as aperiodic structures in materials?
It is known that certain aperiodic structures appear in quasichrystals. For instance, Daniel Schechtman and Ilan Blech discovered that the aluminium-manganese alloy Al$_{6}$Mn has no translational ...
- 1,053
3
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1
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237
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What makes a book (or a stack of paper) so sturdy under pressure?
I've watched an experiment where they compress a book with a hydraulic press, and the book appears to stay relatively intact under that pressure. It is mentioned that the hydraulic press has a 100-ton ...
- 175
4
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117
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How small can velcro be?
Note: "fiber" refers to individual hooks and/or loops.
Imagine two flawless graphene sheets, one with atomic diameter hydrocarbon loops attached to one face, one with atomic diameter ...
- 657
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2
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138
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Material which changes color with charge
Is there a material which changes color when electrically charged (positively or negatively, doesn't matter)? If so, how does it work? If not, is it theoretically possible, and if it's not possible, ...
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1
answer
113
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Can I roughly estimate thermal expansion by an inverse of the bulk modulus?
I am browsing the materials project, and want to find which materials expand more when heated. However, expansion coefficients are not given there. There are bulk moduli, and elastic constants ...
3
votes
1
answer
253
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Densest substance under STP?
The densest pure element is said to be osmium at $22.59~\rm{g/cm}^3$ (with iridium a close second).
Wondering for a long time if pure osmium is also the densest substance - or could there be an alloy ...
- 41
4
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1
answer
67
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Asymmetrical meniscus in certain glassware
I work in a lab that does tests on water samples, and one test we do measures COD or Chemical Oxygen Demand. For quality control, we have a COD standard which contains a certain amount of Potassium ...
- 41
2
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41
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How can I remove a layer of Silica from a rough IN718 surface?
Our rocketry group is designing a biliquid ethaLox Inconel 718 additively manufactured chamber.
We are looking into using Tetraethyl orthosilicate as a fuel additive to reduce the heat flux in our ...
- 21
34
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2
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5k
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Why can no other chemical elements be used for making a light bulb filament?
As far as I can see from this Wikipedia article on the incandescent light bulb, there have been only four types of light bulb filaments: those made of carbon, those made of osmium, those made of ...
- 665
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52
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Are there any solids that are not neutron reflectors, nor neutron moderators?
Is there any solids that lets neutron pass through it (without reflecting or moderating them) that is not air?
Thanks in advance :]
EDIT: clarification
-1
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1
answer
70
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Is it possible to form materials without chemical bonds or reactions?
Preface:
I'm trying to study and think on what possible forms of life may exist near absolute 0, and from what I've read, chemical reactions practically don't take place near absolute 0 whatsoever, ...
- 29
1
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1
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84
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Can oxides of uranium be used to color aluminium oxide based gemstones, or diamonds?
Rubies and sapphires are chemically equivalent to the mineral corundum, with the exception of transition metal impurities that impart different colors to the aluminium oxide. Uranium is not a ...
- 21
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670
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What makes silicone sticky?
I've read from 3M's Adhesion Science articles and this StackExchange question that there are three types of adhesion: chemical, physical, and electrostatic.
I'm curious about what makes silicone ...
- 11