Good question and valuable responses.

Thanks for all.

SiC at 200W/mK might be the best you can do on a budget

https://global.kyocera.com/prdct/fc/list/tokusei/denndou/index.html

Dear Peter,

Thanks for your answer, but copper has higher thermal conductivity (400 W/mK). We need 500-1000 W/mK.

Dear Dmitry,

I think silver-diamond composite may be suitable for you. Please check this article:

Article Silver-based diamond composites with highest thermal conductivity

Dear Pawel,

Thanks a lot for this interesting paper.

I wonder if such materials are commercially available?

Dear Dmitry,

I have no idea but you can always contact the author of this article and ask if they can provide you such a substrate.

Best regards

May be this can help you:

Which metal has the best thermal conductivity?

7 Answers📷Steve Blumenkranz, Mechanical EngineerAnswered Feb 6 2016 · Upvoted by Alessandro Fais, MoS and BD in Materials Engineering, PHD in Metallurgical Engineering · Author has 5.1k answers and 3.2m answer views

Generally, the metal matrix composites containing aluminum with diamond or silicon carbide added and also copper with the same additives have the highest easily purchased thermal conductivity (500W/m-K) of solids in a useful form. Diamond itself is much higher. See ALUMINUM DIAMOND | By contrast, pure aluminum is around 220W/m-K, aluminum nitride 285W/m-K, copper is around 390W/m-K and silver is around 410W/m-K. 

https://www.quora.com/Which-metal-has-the-best-thermal-conductivity

Dear P. Grima Gallardo,

Many thanks for this useful info.

Graphite foil has high thermal conductivity (400-600 W/mK) in horizontal direction (in plane direction), but (15-30 W/mK) in vertical direction, I sugest to cut it into 10mm pecies and attach them together face to face in vertical direction. Finally, you can place your sample over the horizontal direction which has highest thermal conductivity

Good question and valuable responses.

Thanks for all.

Dear Ali Taha Abdel-Motagaly,

Thank you for your answer.

Can you provide any references?

https://link.springer.com/article/10.1007/s11664-012-2177-4

https://www.sglgroup.com/cms/international/products/product-groups/eg/specialty-graphites-for-thermal-management/material.html?__locale=en

http://www.beyondmaterials.com/GraphiteFoil.html

OK, thanks!

Dmitry, I don't know your applications, but carbon nanotubes & their composites will be the right choice. The calasical composites as ZrB, ZrSiC....Hf.... were checked in 50t 60t years ago.

FYI only, spidroin- spider protein have biggеr then Cu!

Best,

Valery,

Don't you mean that spider silk has thermal conductiviy higher than Cu?!

Yes Dmitry, we have a lot of experience with this material, including as hybrid nanocomposites and thin films.

Dear Valery,

I would highly appreciate any links (on both hybrid nanocomposites and spider silk).

Дмитри здравей, ще подготвя необходимите връзки/статии и ще Ви ги изпратя скоро. Относно нагряването на Cu, може да използвате плазмена аргонова/водородна горелка или най-добре плазмена горелка на базата на Браунов газ. Също, ако имате под ръка импулсен лазер с висока честота на повторение на импулсите и дълги импулси- мс/мкс с подходяща дължина на вълната.

Dear Dmitry,

Links/articles:

Development of New Smart Materials and Spinning Systems Inspired ...

https://www.frontiersin.org/articles/10.3389/fmats.2015.../fullПревод на страницатаот J Cheng - ‎2016 - ‎С позовавания в 5 - ‎Сродни статииFront. Mater., 12 January 2016 | https://doi.org/10.3389/fmats.2015.00074. Development of New Smart Materials and Spinning Systems Inspired by Natural Silks and Their Applications. image Jie Cheng1 and image .... On the other hand, the GPGGX motifs form type II β-turn structures, and the GGX motif forms a 31-helix, ...

https://www.mdpi.com/2073-4360/9/9/437/pdf

Best,

Valery

Dear Valery,

Thanks for your answers.

Link

https://www.frontiersin.org/articles/10.3389/fmats.2015.../

doesn't work?

Dmitry, this is the same.....please try by google directly.....have some problem....

[PDF]Development of New Smart Materials and Spinning Systems Inspired ...

https://pdfs.semanticscholar.org/.../349cdbea6d9138e63886bc...Превод на страницатаот J Cheng - ‎2016 - ‎С позовавания в 5 - ‎Сродни статии12.01.2016 г. - of natural silk is its outstanding toughness, which is superior to that of ... have inspired researchers to develop new smart materials, which is the .... On the other hand, the GPGGX motifs form type II β-turn structures, and the GGX motif forms a 31-helix, both of which convey extensibility to the dragline fiber.

ОК, thanks!

You are welcome Dmitry !

Hi,

I have used pyrolytic graphite sheet, highly anisotropic, produced for instance by Panasonic company. They have different versions depending on level of crystallinity, having conductivities 700 or 1400 W/mK. In some inert atmosphere, the temperatures above 1000 degC are available.

Dear Viliam,

Thanks for your reply.

It looks like the graphite sheet has high thermal conductivity in longitudinal direction, whereas we need high conductivity in transverse direction.

Unfortunately, you're right. I overlooked this point. Then you can try CVD diamond substrates. Monocrystals are very expensive, polycrystallines are quite cheap but have hindered conductivity. Of course, the price depends on area, affordable only up to 1 cm2.

Will they resist to temp. of ~1000K?

In oxygen environment the oxidation takes place at about 700 degC, so it is a bit below 1000K. In inert atmosphere, the grafitization occurs at 1700 degC. I know it is not that stable.

Oxygen is disaster. 700 deg C is probably OK though.