High-alumina glass technology

Question

High-alumina glass technology

rcbaker (Materials)

(OP)

12 May 03 12:37

I am interested in ultramicrotome technology. As it happens, the sharpest knife material is a freshly broken glass edge made at about a 45 degree angle. This gets dull after only about a dozen cuts. Also the nanometer-sharp knives get dull when stored, probably due to surface micro-corrosion,leaching of sodium ions. Borosilicate is not suitable for some reason, likely because it does not score and break cleanly.

I suspect that high-alumina glasses might be both harder and more corrosion resistant. I remember reading that such a hard glass may have been tried for watch bearings at one time aqs a substitute for sapphire/alumina. Are any high-alumina glasses commercially available in flat form? --rcbaker

oldglassguy (Materials) · Answer 1 · 2003-06-13 21:21:55

Interesting project!  I have not tried their web site, but suggest that you try Schott and/or Corning for the glass.

Our lab has had very good success propagating and controlling glass fracture using a new technique.  We achieve VERY clean, straight fractures, and can make those parallel a score (made with a glass cutter) at a distance of no more than half of a millimeter without letting the fracture divert from our intended line into the score.  I have never tried to run a fracture at any angle other than perpendicular to the surfaces of the plate, but believe that we might be able to produce your 45 degree fracture.

You are correct about deterioration of the cutting edges by corrosion.  Atom migration due to field changes caused by the fracture is another factor. You may think of that as the effect of the surface tension on the thin material at the blade edge.  The presence of ANY water vapor will accelerate BOTH the corrosion and atom migration problems.

Because it will be difficult to store your blades, perhaps you should build a gadget that makes them as you need them (probably two at a time).

90abc (Chemical) · Answer 2 · 2003-06-22 06:32:37

i am intresting in safety glass i.e its chemistry, manufacturing ,properties ,applications etc.can u help me?

JimMetalsCeramics (Materials) · Answer 3 · 2003-07-19 18:41:33

I assume the glass works because it is fully amorpous. The alumina would probably reduce this. You may want to look at either:

-chemical treatment of the glass
-trying a nanoscopic ceramic, or
-coating (e. g., TiN) the glass' knife edge.

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High-alumina glass technology