The Amazing Properties of Glass-Ceramics (GC Part 1)

The video discusses how the property of "zero-expansion" is achieved in glass-ceramics.

00:00 Intro
01:10 The discovery of glass-ceramics at Coning
02:12 Thermal shock exeriments
06:46 Coefficient of thermal expansion explained
10:12 Measuring CTE if glasses and glass-ceramics (experiment)
14:05 CTE measurement results
17:11 creating negative and zero CTE
20:17 Crystallization and nucleation
22:25 How glass-ceramics are made in practice
25:14 How to make crystallites visible (experiment)
26:15 light scattering in glass ceramics (+ simulation)

If you want to know more about this subject, I would suggest a book by Bach (editor) et Al. named "Low Thermal Expansion Glass Ceramics" Publised by Springer. ISBN 3-540-58598-2. It's quite expensive and rare but occasionally it is offered second hand at reasonable prices.

I displayed several 3rd party images under fair use policy. Here are a few references (the list is not complete). If your image link is missing here, please contact me and I will add a link to the required URL:

End tune: "More to Light" by LIAM Fullersheit (in the Trippy Joint Remix by Jerome V).

[nordithen]

It's amazing that educational content of this quality is freely available.

[peterschrauth]

It is understood that Dr. Stookey dropped that first sample of glass-ceramic as he removed it from the furnace. (Anyone who has handled non-freshly-made hot glass with metal tongs knows how slippery it can be.) When it bounced instead of shattering, he knew something was different.

I had the opportunity to meet him at Sullivan Park Research Campus in 1986, after he received the National Medal of Technology. Dr. S. Donald Stookey is one of multiple legendary people in the history of (Corning Glass Works) Corning Incorporated. A derivative of Photoform(r) is still a key material that is used in putting well-controlled light into optical communications networks.

[josephchristman]

This guy is the man. I work in optics as a mechanical engineer, and he just fills in the gaps with the optical engineers with such grace

[larryslobster]

18:11 LiAlSi₂O₆ shows negative thermal expansion because its crystal structure favors rotations of rigid SiO₄ and AlO₆ units over linear bond expansion when heated. These rotations effectively pull atoms closer, causing the material to shrink slightly rather than expand. Very interesting property!

[bluecollarmax]

I am a master machinist. I'm pretty sure the error with your aluminum sample was BECAUSE its extruded. It is pre stressed, as it were, in the long axis. I deal with this issue when making precision parts. A piece of billet aluminum or cast tooling plate would yield results much closet to book values. Cool video, and the explanation of the molecular behavior helps me to understand better the stresses in metals. thank you. I love learning.

[TunioMir]

LOLOLOL was not expecting the Ultra Spherotron breakdown! (No need to apologize, we all know you couldn't resist)
haha

[TheloniousMonk]

Very nice!!! As a retired glass scientist I congratulate you for spreading some real materials science to the masses!!!!

[joaovitorcampos]

I am a researcher working on glass ceramics, and your video was like poetry to me ❤

[twoiko]

The combination of relatively simple descriptions, personal testing, and finally, detailed scientific analysis; all wrapped up with well-known names in the industry is just -chef's kiss.
I feel like I've been looking for this exact video for years, and I finally feel like I can navigate the intricacies of glass-ceramics in ways I've always wanted to.
Now, I wouldn't mind a follow-up video going into more details chemically, but that would likely be a different channel lol

[synterr]

Spherotronic made my day! Thank you! :)

[AB-wfek]

11:00 Mmm, sounds like a pretty hollow apology. I didn't see a lot of effort in trying to resist.

[benjaminbeard]

The fact that you are holding that last sample (that didn't crack) with your bare hands speaks volumes.

[cipaisone]

Amazingly clear and interesting.
The ultra spherotronic killed me :)

[georgH]

Yours are among the TOP, TOP of YT videos. Excellent, as always.
I've always found optics and light fascinating, and of course have always been intrigued by glass-ceramics or "vitroceramics" as we call it.

[costa_marco]

I am a simple man, i see a video from Huygens Optics, I click like.

[cylosgarage]

A new video from Jeroen always makes my day!

[nltmjll]

"How glass-ceramics are made in practice" is a really good segment. Thank you.

[nameismetatoo]

That crystal structure for Photoform is stunningly beautiful.

[rrooggiieerr]

The first thing that I thought of at 9:10 was that a CTE of 0 ± 0.5 would mean a negative CTE would be possible which meant the material could shrink when heated, which is counter intuitive to me. Later you explained this is actually the case. Very interesting.

If I remember correctly polarised light makes it possible to show the internal (temperature) stress within glass. Using a polarised light source and a 90° polarisation filter for the camera lights up the stress within the sample. It would be interesting to see that for all the samples during the cooling down stress test at 2:30

[bloodakoos]

currently studying science and characteristics of materials in college, youtube really does know what to recommend