# Glass an metal properties when heatet and cooling down again.

Hello,
I am trying to put different materials in to glass in a oven i know that Copper and glass react equal when heetet to about 1200 degrees and
cooling down again should have same properties.
Is there other materials and metals that has the same properties..
What is that process called where two materials is heatet up and cooled down again with same properties?
How do i mesure this?
Is there some cards telling how this works like in the periodic system?
Does silver and glass have the same properties expanding and deexpanding when cooling down again..
is there other materials that does the same ex. gold or other?
Søren M
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Søren M wrote:

Well, I think that the property that you are discussing might be the "Thermal Expansion Coefficient" which is also called thermal coefficient of expansion and abbreviateed sometimes as TCE.
If both materials expand about the same amount, then they don't push or pull on each other, and they won't break apart when they cool down after being melted together.
There are different glasses, as well as different metals. And the glasses have somewhat different thermal expansion coeffients from each other.
Metals that have higher melting points have lower TCE, and of course, those with lower melting points have higher TCE.
And for glasses, those with higher melting points have higher TCE....
A complication is that the CTE isn't really constant with temperature, and usually rises somewhat with temperature. That data is harder to get.
Mostly the data that you will easily get is for room temperature and maybe an average behavior for a hundred degrees or so. Because most ordinary engineering applications are at room temperature on not "white hot", that is the easiest way to give useful informatin.
The units are (length change) per(/) (unit length) per (Degree) or in the SI system meters/meter/oC and the lenggth change per unit length part is measured in parts per million or 10-6.
Plastics range from 200 to about 27 ppm/oC
Metal..or..glass...........TCE ppm/oC (very approximate)
Magnesium..................40 Zinc.......................35 lead.......................30 Aluminum...................20-25 copper.....................21-18 steel(s)...................19-15 gold.......................14 Nickle alloy...............18-11 Ferretic Stainles Steel....11-9 Titanium...................11-8
tungsten....................5
low melting glass...........10-4 (?) estimated borosilicate glass..........3 (cooking glassware) fused silica................1
If the glass is low melting, then the total mismatch between the glass and the metal is decreased somewhat because the temperature change from melting to room temperature is smaller.
Ordinary glass bottles for food or soda pop are usually low melting glass compositions because it costs money to heath them up to make bottles, and the hotter you heat the glass, the more money it takes.
There may be some easy ways to measure these thermal expansion coefficients yourself, but I am unaware of them. Commercial instruments that do are often called dilatometers.
--
1) Eat Till SATISFIED, Not STUFFED... Atkins repeated 9 times in the book
2) Exercise: It's Non-Negotiable..... Chapter 22 title, Atkins book
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On Sat, 05 Nov 2005 07:06:33 -0600, jbuch

<snip>
As you have demonstrated, those with higher melting temperatures have LOWER coefficients of thermal expansion.
Note that glasses do not have melting points as such. Littleton Softening Point is a more meaningful criterion.
--
Terry Harper
URL: http://www.btinternet.com/~terry.harper /
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i -> I heatet -> heated mesure -> measure Does -> Do Is -> Are does -> do
That data -> That datum data..is -> data..are
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This is a fairly specialised topic, I have seen gold in art glass, but I do not know the composition of the glass. Have you tried rec.crafts.glass
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Søren M wrote:

Soft metals are easy to enamel when compared to materials like iron and steel (cloisonné is usually enamel on copper). I assume applying soft metal to glass would not be very difficult. I would think the metal would deform readily and releve some stress - Provided the thermal expansion of the glass is not to high. Gold is also used to fuse or braze large metal to ceramic parts (for special - cost is no object applications)
Gregg
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On Sat, 5 Nov 2005 12:38:18 +0100, "Søren M"

The electronics industry has produced sealing glasses for metal leads to pass through the walls of glass (or metal) vessels for many years. To produce effective seals often calls for the use of a number of glasses with gradually increasing or decreasing CofE to get a strain-free seal.
These are called "graded seals". If you put "Sealing glasses" into Google, you will get a lot of useful links.
--
Terry Harper
URL: http://www.btinternet.com/~terry.harper /
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Terry Harper wrote:

And before that, folks used the Housekeeper seal, which is a copper-to-glass seal. Nothing special about the glass, but the copper is thinned so that it can take up stresses induced by the CTE mismatch. I think it is treated to form a brown oxide layer before being fused with the glass. After the junction is formed, the copper (as viewed through the glass) is bright, so I suppose the copper oxide is dissolving in the glass or something. It was commonly used in vacuum work.
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