Advice needed for choosing material

I'd like to get some advice for transparent material,
they need to be stiff and tough.
I have tried some plastics but they are not stiff enough, and glass is too
brittle.
Thanks!
Reply to
Henry
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Transparent in what wavelength window? Light scattering and inclusions? Problems with refractive index and Abbe number? Surface scratch and dig specs?
HOW THICK? WHAT AREA/THICKNESS? What temp? What chemical environment? What loading? Stress birefringence? For how long?
Toughened polystyrene or crosslinked+toughened acrylic. Pyrex.
You can have stiff (hard, brittle; glassy) or you can have tough (elongation to failure, notch failure resistance,; leathery). If you want both, the price just skyrocketed if it can be done at all.
Reply to
Uncle Al
Did you try pMMA (acrylic) or polycarbonate? If the transparency requirement is not very high you can consider amorphous nylons, and transparent epoxies.
Ernie
Reply to
Ernie
Single-crystal Indian or Australian muscovite book mica. Available in crystal-clear flawless sheets and plates from 10 microns to more than 1 centimetre thickness, more than 1 decimetre diagonal length.
Reply to
Mark Thorson
the Young's mudulus need to be more than 20 GPa, I need to make a small thin plate(3mm deep, 20mm diameter) with some small holes through the plate using the material. and later I will apply some presure(20 MPa) on the plate. so I am afraid some materials are too brittle...
Reply to
Henry
Mica isn't brittle at all. A strip 100 micron thick (normal to the crystal plates) x 1 mm x 100 mm would be easy to tie into a knot. I could probably tie several knots in that, without breaking it. You can drill it, along the axis normal to the plates.
20 MPa is no problem, applied evenly. Is that 20 MPa applied as a liquid or gas? What is its composition? If it penetrates the mica between the plates, and then the pressure is suddenly released, and the pressure medium underwent a liquid-gas transition, the mica could puff up. That's like vermiculite -- which is mica infiltrated with water, then puffed by rapid heating.
Reply to
Mark Thorson
Hi Mark, thanks for your advice. I have found some "Muscovite Mica" Rigid Sheets from Mcmaster. the 10" x 12" x .125" (Part Number 8779K51) for 61.75$. Is this the right mica?
Thanks again!
Reply to
Henry
Mucovite is without question the right mica. I don't know anything about the McMaster material or your application, so I can't say whether that material would work. You'll have to read their specifications.
Note that mica sold for electrical insulating purposes is often consolidated from smaller pieces This sort of mica is not transparent. For transparency, you must use single-crystal book mica.
Reply to
Mark Thorson
How about some clear casting polyester with glass fiber reinforcement, or basic clear epoxy with good wetting agent and glassfiber.
Deaerate the wet laminate in vacuum, and press between releasing agent treated and polished glass plates in vacuum bag. Needs some practice, but I once made pretty good ones with this technique for control window purposes.
Samu
Reply to
Samu Aalto
You might do better with synthetic fluorophlogopite used in steam boiler sight glasses. The Kirk-Othmer Encyclopedia has a large section on synthetic mica.
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Reply to
Uncle Al
The company people told me that " the fluorine mica is too soft and cleavable", is it true?
> Henry wrote: > > > > Hi, > > I can only found 100 micron thick mica on Mcmaster, Where could I > > found thicker one like 0.5 or 1 cm? > > You might do better with synthetic fluorophlogopite used in steam > boiler sight glasses. The Kirk-Othmer Encyclopedia has a large > section on synthetic mica. > >
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Reply to
Henry

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