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Metal or Polymer with Differing Properties

11/26/2017 8:45 PM

Is there a material, whether polymer or otherwise, that conducts heat but resists electric current ?

this material would make Peltier principle very effective.

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#1

Re: Metal or Polymer with Differing Properties

11/26/2017 9:28 PM
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#2

Re: Metal or Polymer with Differing Properties

11/26/2017 9:41 PM

..."A heat transfer material comprised of a polymeric material and a nitride or oxide is provided and is thermally conductive, but electrically non-conductive. The polymeric material may be silicone rubber, and the nitride or oxide may be aluminum nitride, boron nitride, silicon nitride, aluminum oxide or beryllium oxide."...

https://www.google.com/patents/US7321107

You can call it Gadepallium....

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#3
In reply to #2

Re: Metal or Polymer with Differing Properties

11/27/2017 1:47 AM

"You can call it Gadepallium...."

That will be totally lost on OP.

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#4

Re: Metal or Polymer with Differing Properties

11/27/2017 1:56 AM

I entered this into the Google searchbox, copied directly from your post:

conducts heat but resists electric current

The Google search engine returned a bunch of entries. Here are the first 6:

Conductors, Insulators, and Electron Flow | Basic Concepts Of ...

https://www.allaboutcircuits.com › ... › Basic Concepts Of Electricity

Electrical conductivity is analogous to the transparency of certain materials to light: materials that easily “conduct” light are called “transparent,” while those that don't are called “opaque. ... Glass, for instance, is a very good insulator at room temperature, but becomes a conductor when heated to a very hightemperature.

ELECTRICITY Flashcards | Quizlet

https://quizlet.com/3897174/electricity-flash-cards/

static electricity. the buildup of charges on an object. electric current. the flow of electrons. current electricity. a kind of kinetic energy that flows as an electric current. conductor. a material that carries electricity well. insulator. a material that does not conduct electricity well. electric charges. Units of electricity. static electricity.

Electricity Flashcards | Quizlet

https://quizlet.com/7781258/electricity-flash-cards/

needed one that would conduct electric current, but would offer enough resistance to make the materialheat up and glow. Superconductors. Scientists have discovered that some materials become superconductors at very low temperatures. A superconductor is a material that has no electrical resistance. A superconductor ...

solid state physics - How can a material conduct heat but not electricity ...

https://physics.stackexchange.com/.../how-can-a-material-conduct-heat-but-not-electri...

Jun 28, 2015 - Electricity needs charges particles (or quasi-particles) to conduct. Heat can be conducted with almost any quasi-particle. Diamond is one of the best conductors of heat in existence, and it's because of phonons, ie quasi-particles of lattice vibrations, which are strong because the diamond lattice is strong.

Why does electrical current make heat? - Qrg.northwestern.edu

www.qrg.northwestern.edu/.../thermal/3-why-does-electrical-current-make-heat.html

Some conductors are better than others, but none are perfect, and all resist electron flow to some extent. When electron flow is resisted, some of the energy in the electrons does not travel through all the way. Because energy is conserved, the energy that was moving the electrons forward is converted to heatenergy.

CR4 - Engineering Forum | Engineering360

cr4.globalspec.com/

11/26/2017 posted in New Technologies & Research by Gadepalli Subrahmanyam. Is there a material, whether polymer or otherwise, that conducts heat but resists electric current ? this material would make Peltier principle very... Views: 13, Comments: 2. Last comment 11/26/2017 by SolarEagle ... You've visited this page many times. Last visit: 10/16/17.

The 4th entry gives your answer.

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#5

Re: Metal or Polymer with Differing Properties

11/27/2017 3:23 AM

All non-metals have those characteristics.

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#6

Re: Metal or Polymer with Differing Properties

11/27/2017 7:06 AM

Have you ever heard of Heatsink Compound (sometimes AKA Thermal Grease)?

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#7

Re: Metal or Polymer with Differing Properties

11/27/2017 7:10 AM

Sapphire. It's neither a metal nor a polymer, but it's an electrical insulator with excellent heat conductivity. Industrial forms, like sapphire windows, aren't as expensive as sapphire gems.

By the way, sapphire is essentially the 'transparent aluminum' that Scotty wanted in that Star Trek movie about the whales.

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#8

Re: Metal or Polymer with Differing Properties

11/27/2017 7:28 AM

Please describe the options under consideration.

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#9

Re: Metal or Polymer with Differing Properties

11/27/2017 7:47 AM

If you have an unlimited budget, diamond is an electrical insulator but a very good heat conductor.

"Thermal conductivity[edit]

Unlike most electrical insulators, diamond is a good conductor of heat because of the strong covalent bonding and low phonon scattering. Thermal conductivity of natural diamond was measured to be about 2200 W/(m·K), which is five times more than copper. Monocrystalline synthetic diamond enriched to 99.9% the isotope 12C has the highest thermal conductivity of any known solid at room temperature: 3320 W/(m·K).[37][38] Because diamond has such high thermal conductance it is already used in semiconductor manufacture to prevent silicon and other semiconducting materials from overheating. At lower temperatures conductivity becomes even better, and reaches 41000 W/(m·K) at 104 K (12C-enriched diamond).[38]

Diamond's high thermal conductivity is used by jewelers and gemologists who may employ an electronic thermal probe to distinguish diamonds from their imitations. These probes consist of a pair of battery-powered thermistors mounted in a fine copper tip. One thermistor functions as a heating device while the other measures the temperature of the copper tip: if the stone being tested is a diamond, it will conduct the tip's thermal energy rapidly enough to produce a measurable temperature drop. This test takes about 2–3 seconds. However, older probes will be fooled by moissanite, a crystalline mineral form of silicon carbide introduced in 1998 as an alternative to diamonds, which has a similar thermal conductivity.[5][27] "

https://en.wikipedia.org/wiki/Material_properties_of_diamond

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#10

Re: Metal or Polymer with Differing Properties

11/28/2017 8:58 AM

REQUIREMENTS

Please, state the requirements. Note: you can not design nothing if you don't know the requirements.

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#11

Re: Metal or Polymer with Differing Properties

11/28/2017 9:33 AM

Really Thin Thermoelectric Device Opportunity:

Looking in Wikipedia for thermoelectric materials produces this fragment:

-------------------------------------------------------------------------------------

Graphene

Due to the unique nature of graphene, it is possible to develop a thermoelectric device based on it with an extremely high Seebeck coefficient.

One theoretical study suggests that the Seebeck coefficient might achieve a value of 30 mV/K at room temperature.

------------------------------------------------------------------------------

Looking up graphene in Wikipedia further reveals:

in 2004 Geim and Novoselov extracted single-atom-thick crystallites from bulk graphite[7] and transferred them onto thin silicon dioxide (SiO
2) on a silicon wafer,[189] which electrically isolated the graphene.

-----------------------------------------------------------------------------------

Noticing the thermal conductivity of graphene here:

The room temperature values of the thermal conductivity in the range ∼(4.84 ± 0.44) × 103 to (5.30 ± 0.48) × 103 W/mK were extracted for a single-layer graphene.

----------------------------------------------------------------------------------

It strikes me that a nano-composite of quartz(silicon dioxide) and graphene might produce what you asked for including the thermoelectric device itself. The quartz is quite a good insulator and heavily used in the semiconductor industry(well understood with commodity costs.) The graphene is both a great conductor to wire your peltier device and an outstanding thermoelectric material. The composite could be incredibly thin and possibly cheap. If one could cheaply apply or grow graphene on the surface of sputtered quartz the composite might win the cannonical frugality award. Being extremely thin might mean it could be applied to (or perhaps manufactured on) a lot of different materials and shapes. This would mean intimate contact with the cooler and the item cooled (perhaps even textiles) for optimum application efficiency. With some research it might be designed to implement either the Seebeck and/or Peltier effects.

This is, of course, quite speculative but also very promising. The diamond and sapphire are great electrical insulators but typically quite expensive so they should be thin to save cost. I just thought quartz glass is probably a good enough insulator at thermoelectric magnitude voltages and if the insulator is really thin perhaps a great advantage might be seized by making the thermoelectric device and its electrical conductors really thin as well. Really thin thermal insulators are still very close to thermal conductors. An alternative to glass might also be diamond like carbon(DLC) which can behave a lot like diamond and has moderately cheap manufacturing costs. See magnetic recording tape with its DLC coating.

thewildΩtter ¥ ! <- thewildotter with a yen for thin costs.

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#12

Re: Metal or Polymer with Differing Properties

11/28/2017 11:46 AM

There are many non conductive thermal compounds and adhesives available. See link below for one of them.

http://www.arcticsilver.com/arctic_alumina_thermal_adhesive.htm

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#13

Re: Metal or Polymer with Differing Properties

11/28/2017 2:20 PM

Like Rixter I'd have gone for Diamond as easily the best thermal conductor and a very good electrical insulator.

But, even if you find something really cheap with the stated properties how on earth are you going to make any kind of TEC if it doesn't conduct electricity?

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#14

Re: Metal or Polymer with Differing Properties

11/28/2017 7:50 PM

I think it is time I react to our members' views.

first of all, I had clearly mentioned the possible application: Peltier or you may call it TEM. Now, as I understand, A Peltier module converts electric current to heat faster than resistance does, and of course, as a bonus produces COLDNESS too, without any movement whatsoever. The trick lies in removal of heat from the P N junctions fastest, at the same time using the heat to advantage.

Now, our friends have suggested all sorts of precious stones, that included the costliest, viz., Diamond, and Saphhire, as if the Peltier module was intended to heat or cool, a Monarch's head, via a crown.

An engineer is supposed to do a job for a shilling, when others could do the job for a pound, and not vice versa. So I naturally expect a solution that is econmical.

Still it is elusive.

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#15
In reply to #14

Re: Metal or Polymer with Differing Properties

11/28/2017 8:19 PM

I think that you may be overestimating the forum member's knowledge and education in chemistry and materials.

This is not a site where scholars congregate to discuss emerging materials technology regularity.

Searching the internet is the sum total of the advanced materials technology possessed by most here.

Good luck.

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#16
In reply to #14

Re: Metal or Polymer with Differing Properties

11/29/2017 6:09 AM

Yes but the second part of my reply renders the first irrelevant:-

"But, even if you find something really cheap with the stated properties how on earth are you going to make any kind of TEC if it doesn't conduct electricity?"

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#17
In reply to #16

Re: Metal or Polymer with Differing Properties

11/29/2017 9:31 AM

ThermoElectric Device Geometry Design

a real device geometry example
Notice the geometry is repetitious but intricate.

A big problem is that thermal and electrical conductivity are very positively correlated. The semiconductor is going to conduct heat right back across the junction continuously as it is carried against the thermal gradient by the electric current(I will leave it to you to look up what exactly the Seebeck and Peltier effects are.) So the device architecture has a massive inherent flaw limiting the efficiency. This problem can be reduced some by careful design of the geometries involved. There is considerable research going on to measure and design geometries with desired resulting properties.

At Universities researchers like Jenna Walwrath are attacking these problems.
There are significant similarities with electronic semiconductor manufacturing dilemmas. There may even be opportunities for gleaning power with thermal gradients to locally power subsections of microprocessors by integrating them on a nano-scale.

So, in answer to your stated dilemma. TEC devices do conduct electricity. The real question is where exactly do they do it and how does that relate to the thermal flows. How relatively thin and thick the various parts are can have a huge impact on what micro and macro scale behaviors you get.

thewildΩtter ∫ !

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#18

Re: Metal or Polymer with Differing Properties

11/29/2017 9:40 AM

Gadepalli: you are understanding better your question-heat-design based on material properties. First of all; polymers and metals doesn't react in the same way to an electrical field. So you can use both materials to build up your model. For example use the metal (such Al) to remove the generated heat in the polymer. Regards.

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Users who posted comments:

Gadepalli Subrahmanyam (1); JohnDG (1); Jose1 (2); lyn (2); Mikerho (2); PWSlack (2); Randall (2); Rixter (1); SolarEagle (1); sptilton (1); thewildotter (2); Usbport (1)

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