Forming glass shapes: Lowering the 'softening temperature' via electric field

Forming glass shapes: Lowering the 'softening temperature' via electric field
The experimental setup inside the modified Applied Test Systems model 2605 pneumatic creep tester, in which the anode was located at the top of the sample and the cathode at the bottom. The system was electrically insulated from the rest of the furnace. Credit: Jain

On a serendipitous occasion, while attending a conference and listening to Rishi Raj, a professor of mechanical engineering at the University of Colorado Boulder, speak about the remarkable effect of moderate electrical fields on lowering the sintering temperature of certain ceramic powders, Himanshu Jain, a professor of materials science and engineering at Lehigh University, began to wonder if a similar phenomenon was possible in a glass—because he knew that the implications could be huge for glass technology.

The two professors chatted briefly during a coffee break and a spontaneous collaboration to explore the possibility began.

As the team of researchers at Lehigh University and the University of Colorado Boulder discovered and describe in Applied Physics Letters, from AIP Publishing, a similar, albeit slightly different, phenomenon is indeed possible in a glass.

The basis of the team's work and experiments is fairly straightforward: glass softens upon heating in a furnace, so it can be readily observed as the onset of rapid deformation under the application of a compressive load. "We wanted to discover whether or not 'softening behavior' could be significantly enhanced by the additional application of an ," said Jain.

So they ran a series of experiments centering on comparing softening temperatures while a rectangular piece of glass was heated at a constant rate under the simultaneous application of mechanical load, as well as with an electric field. Then, to "establish the generality of phenomenon and to develop an understanding of underlying mechanisms, we performed experiments on a few different glass compositions of varying properties," he noted.

Forming glass products into specific shapes requires high temperatures, which translates to consuming a considerable amount of energy. "Electrical heating is widely used in the initial melting process, but not for 'forming operations,' which require glass to be soft and easily deformable, while also keeping the desired shape," explained Jain.

The team's approach, which "lowers the softening temperature by electric field, offers the potential to save significant amounts of energy, but may also end up leading to innovative methods of 'micro-forming' because electric fields can be manipulated much more precisely and selectively than plain old heating," he added.

For the team, actually observing the softening of glass at a significantly lower furnace temperature was the most exciting part of their experiments. There were, however, some surprises along the way. "One of these 'unexpected results' was that soon after the softening of glass, we observed a strong glow coming from the anode region," Jain revealed. "Upon continued application of electrical field, we observed smoke and substantial destruction of the sample."

In terms of applications for the team's work, the results of their study will prove extremely useful for micro- and nano-forming operations in which micro- and nano-scale glass shaping is desirable, as well as for high-precision nanostamping. The same applies for modifying physical properties near electrodes.

"Gaining a better understanding of the underlying phenomenon will help us learn the limitations of glass as an electrical insulator," noted Jain. "There's tremendous interest in using glass as a supercapacitor for energy storage, for example. But it's critical not to use glass that deforms easily in such applications, so it would be helpful to know in advance how the glass will behave."

Now that the team has discovered this phenomenon of electric field-induced softening of glass, since they're a group of materials scientists, they've moved on to exploring its mechanisms and behavior during various stages.

One way to do this is to perform experiments on a broader variety of glasses with specific characteristics. "This will help us to identify compositions for specific applications that exploit electric-field-induced softening," Jain said.

Their goal now is to further develop electric-field-induced softening for practical applications with an industry partner.

Explore further

Researchers find out why high-performance glass flows, and how fast

More information: C. McLaren et al. Electric field-induced softening of alkali silicate glasses, Applied Physics Letters (2015). DOI: 10.1063/1.4934945
Journal information: Applied Physics Letters

Citation: Forming glass shapes: Lowering the 'softening temperature' via electric field (2015, November 3) retrieved 20 October 2019 from
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Nov 03, 2015
This process should respond to phonic excitation, i.e. atomic and molecular excitation, not sure about electrons. Note the heat changes the available states and the necessary excitation field. So if the object is modulated with the correct phonoms, which might be audio. The electrical-static field will change the superimposed centers; that is, the measurements of the field and the distance between positive and negative "body" positions will be altered. Think of it this way, the E field at any point is the same as the E field from a charged particle at a calculated distance. You may use superposition to define it as any number of particles, even the actual. But note the field location, timing and energy. From this, known science, one may eventually define necessary fields to alter the object. Wither it's possible or not can be simulated. Best simulation would be with possible capability. I see what's happening but don't have any tools laying around for a proof. Juz say'n.

Nov 03, 2015
You will need some really good people like me. I hate coding but am capable; however, knowing how difficult it is for a single individual. These answers are simpler than Einstein but require a greater effort than a single paper. It's known science. Simply use it. Surprising is sorta childish.

Nov 03, 2015
Please ignore modern theory, what has been done with theory has no basis in intelligence. It's simply a list of puzzles that do not reflect reality! I've written about this, it only effects the PhD programs in theoretical physics which will lead you into the wrong direction. Stick with Maxwell and understand that Newton would have predicted what we see with the perihelion of Mercury as an optical solution not by changing space and time to fit a known measurement Newton had already defined, Dr. E was actually off by a few months, he was pretty mathematically stupid, precision. No body will care if we shoot this completely down except those seeking "Dark Matter" and things like the Higgs, ie. a total misinterpretation of mass. To bad newton didn't know atomic physics.

Nov 03, 2015
Simply superposition of the "+" and "-" poorly defined particles. Logic and correct math is always right! Thanks for showing me this.

Nov 03, 2015
As material scientists, they should probably test out their heating / electrical field effect on pretty much everything the can think of. Science, baby!

Nov 04, 2015
Another numbers free article. What about field strength, current flowing etc?

Nov 04, 2015
yeah ! I love reading these articles when something is actually a physical experiment - who knows what else is out there if random science experiments between totally disparate 'specialities' are
combined and cooperated on with no thought of who-gets-what recognition ! I suspect we may have the answers to all humanities problems. Theoretical science is a waste of time unless it is just a concept to be tested in the real world.

Nov 04, 2015
Is it the field or current that lowers the softening point?

Apply field only and recheck. A field takes no power.

Does soft glass conduct? Why the resister?

I have observed this phenomena many times.

It's called a short.

Nov 04, 2015
It is the field, Elmo. Note that the current is very low.

This is predictable from the electronic model of the atom that Planck first proposed in his original quantum theory, which is another indication of the accuracy of his model, in contradiction to the mechanical model of Quantum Mechanics. An external electric field can pull the electron away from the proton(s) or reduce the required control force.

Did you mean Schrodinger's Cat's QM? Model and QM, 2 different things.

Nov 04, 2015
Well I see QM as only a statistical calculation of how to satisfy the potential with the kinetic and conservation of energy using a wave equation that appears everywhere. Models may be used within the QM equations for better definition, but QM only shows possibility. In other words, all of these states do not exist for each particle at the same time, only within the large number of particles then existence based upon possibilities. When one tries to use QM for a single particle, exactly what would be your expectations, magic? However, empiricism is another issue. Lack of understanding will lead one astray.

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