81
votes
Why can a diamond be broken using a hammer if it's the hardest natural substance known?
Hardness and toughness are not the same
Hardness and toughness are very different qualities in materials and are weakly related.
Hardness is strongly related to the more well-defined quantity of ...
- 35.5k
46
votes
Why isn't 'chemically-strengthened glass' made with potassium carbonate to begin with?
The potassium is not added first because the potassium does not intrinsically make stronger glass, it is the substitution of a larger ion for a smaller one at the surface that does.
To understand why ...
- 12.4k
35
votes
Accepted
Which is the densest gas known?
Perfluorobutane is inert and has almost twice the density of sulfur hexafluoride. It is non-toxic enough that it is used in fire extinguishers and injected as a contrast agent for ultrasound. Boiling ...
- 674
30
votes
What easily accessible material has melting point between 500 °C and 590 °C?
Temperature-indicating or thermo crayons are used by welders. These melt at specific temperatures.
Not as an endorsement, but to give you an idea of what's available, the crayons from McMaster-Carr ...
- 401
26
votes
Why isn't 'chemically-strengthened glass' made with potassium carbonate to begin with?
Chemically-strengthened glass is similar tempered glass in that the outside of the glass is under compression, while the inside is not compressed. If all the sodium in chemically-strengthened glass ...
- 30.5k
24
votes
If you put two blocks of an element together, why don't they bond?
Why, when you bring the two bars together so that they touch each other, do they not instantly bond with each other forming one larger bar or block? ... Why do we need to 'weld' two bars together - ...
- 17.3k
21
votes
Accepted
What makes Gorilla Glass more durable with each generation?
Are there other ways of "chemical strengthening" besides cationic exchange that can be utilized to strengthen the glass, keeping it flexible and less fragile at the same time?
In a word: No.
To ...
- 12.4k
20
votes
What is the @ symbol used for in material science?
The at symbol @ universally means "at the site" or "at the rate of".
It is routinely used in supramolecular chemistry to denote guest@host relationship because
it follows the ...
- 37.4k
20
votes
Accepted
Why use diamond-like carbon instead of diamond?
You balance cost of manufacture and return of investment for the anticipated use.
If you read about the methods of production of diamond-like carbon (DLC), e.g., on Wikipedia, e.g.
«DLC is typically ...
- 28.4k
18
votes
What easily accessible material has melting point between 500 °C and 590 °C?
It might not qualify as 'available at home' but MakeItFrom has a database with engineering material you can search:
MakeItFrom.com is a curated database of engineering material properties that ...
- 2,075
15
votes
Accepted
What does "René" mean in René alloys?
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 ...
- 28.4k
15
votes
Conception and manufacture of the Avogadro Project's (nearly) perfect silicon sphere (and, what is “atomic feeling”?)
Short answer: The success of the project benefitted from many contributors.
According to BIPM and its Avogadro project, there are two spheres (reference). The page equally refers to a publiction ...
- 28.4k
14
votes
Why can a diamond be broken using a hammer if it's the hardest natural substance known?
Diamond has cleavage planes. If you want something nearly unbreakable, try nephrite, which is a tough form of jade used by the ancient Aztecs to make axe heads! Actinolite is another related "tough as ...
- 141
14
votes
Accepted
Can a vacuum on a closed system really “pull” things out of it?
Gasses don't get "pulled", they get "pushed".
When you empty a neon tube, you attach a device with almost no air in it to mouth of the tube.
The air that is in the tube then pushes ...
- 672
13
votes
What piezoelectric materials can be made at home?
The top of my list for exhibiting piezo activity and can be easily purchased and is also transparent..
Quartz
That's about it. It's used everywhere - as an oscillator for quartz crystal watches, ...
- 27.7k
13
votes
Is there a material that ions can pass through but water can’t?
There are so many materials that allow the passage of ions but not water. They are called ion-exchange membranes. I believe you are interested in water purification based on your previous posts. The ...
- 39.1k
12
votes
Rubber composition A13 B13 C20 F17 K11 L14
TL;DR I think you might need two more things to interpret this line: the first code part of the standard, and the standard itself - ASTM D2000 (needs to be purchased).
These descriptors are not ...
- 37.4k
11
votes
Why is gold so popular in nanotechnology?
First, let's look at gold's properties.
Gold is the most malleable of all metals. This malleability alone is very useful in aiding scientists to create such small gold nanoparticles.
Gold also ...
- 154
11
votes
What easily accessible material has melting point between 500 °C and 590 °C?
Name
Formula
m.p./°C
Copper(II) chloride
$\ce{CuCl2}$
498
Barium perchlorate
$\ce{Ba(ClO4)2}$
505
Potassium fluoroborate*
$\ce{KBF4}$
530
Antimony trisulfide (stibnite)
$\ce{Sb2S3}$
550
Calcium ...
- 27.1k
11
votes
Why I am unable to see any electrical conductivity in Permalloy nano powders?
Nanoparticles are often pyrophoric, and may be coated to prevent spontaneous combustion. The particles' surface might be nitrided, or oxide coated, or coated with an organic chemical. Permalloy itself ...
- 30.5k
10
votes
Accepted
Conception and manufacture of the Avogadro Project's (nearly) perfect silicon sphere (and, what is “atomic feeling”?)
First thing I think we have to differentiate between checking the roundness and the roughness (that in the article seems it is called smoothness) these two properties of the surface necessitate ...
- 9,069
10
votes
Accepted
What is the optimal voltage for storing a 3.7 V lithium polymer battery?
The $\pu{3.6-3.8 V}$ range is a good general choice, but it may be battery-specific. The particular voltage for 40% charge may differ for different cell technologies, e.g. various deviations of ...
- 39.4k
10
votes
Why use diamond-like carbon instead of diamond?
Why do you think that would be preferable? A perfect crystal is rather fragile - diamonds are hard, but they also have perfect cleavage - one good hit and you have two diamonds (or a bunch of shards). ...
- 505
10
votes
Accepted
What material properties are unpredictable (not reproducible) but can be measured consistently and at a low cost?
Impossible for a homogeneous material, however ...
basically every nonhomogeneous material fits your description. Say the pattern of microphase separation in a copolymer. Or the arrangement of filler ...
- 12k
9
votes
Accepted
(At what temperature) can salt evaporate?
All substances may have a melting and boiling point. I say "may" because in some instances there can be decomposition, for example, before reaching either temperature.
Sodium chloride has a melting ...
- 346
9
votes
Accepted
Technical name for the holes (missing electrons) in a p-type semi-conductor?
Yes, the technical name is, in fact, an electron hole (typically referred to as simply a hole). It is considered suitable to describe these holes as electric charge carriers with a positive charge ...
- 1,332
9
votes
What easily accessible material has melting point between 500 °C and 590 °C?
There ought to be an alloy with the desired melting point. It doesn't seem to be commercially available, but you could experiment by obtaining tin or zinc, plus copper powder (or scrap brass / bronze),...
- 191
8
votes
Why is gold so popular in nanotechnology?
I don't know why everyone missed this point. At nanoscale materials tends to have some novel physical and chemical properties comparing to its macro scale. One such phenomenon which is seen especially ...
- 2,740
8
votes
Does crystalline glass exist?
As Ivan explained, a glass is by definition amorphous. However, you can take a quartz crystal (silicon dioxide, which is the main ingredient of glass) if it is of high purity and optical quality, and ...
- 9,216
8
votes
Accepted
What are some materials that expand a lot proportionally to heat?
You are looking for thermal expansion and its coefficient. Of course such tables, and diagrams exist
(source)
as it is of relevance in daily live. Thermometers based on liquid mercury, or alcohol, ...
- 28.4k
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