DIY Carbon-Carbon composites

Some background: Carbon-Carbon composites are essentailly graphite strengthed with carbon fibers. They are very strong and heat resistant. They were used as the nose cone and leading edges of the space shuttle, as well as some rocket nozzles. C-C composites are very difficult to make and expensive.

Naturally, I wondered if I could make it myself.
So the idea is, you take graphite, chopped carbon fibers, and an ultra high temp adhesive and mix them together. I found one that is good to 4000 deg. F. (https://www.cotronics.com/WEB SHEETS/904 NP.pdf). (the price is not listed. uh oh)This should give higher temperature performance than steel, but still at least 1000 deg less than pure graphite. As a bonus, you could use something similar to Lamborghini's 'forged composite' process where they press, what looks like, chopped carbon fibers and epoxy into shapes using high pressure and temperature. (https://en.wikipedia.org/wiki/Forged_composite) So the question is, would this work? I believe so.

I'm planning on making rocket nozzles, and carbon-carbon is one of the best materials. This could also be used as the leading edge of fins and nosecones for high performance rockets.

Any thoughts?

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Sounds like a good project. The carbon-carbon I am familiar with dates back to the 80's. I was working with fiber composite gurus from Drexel and Atlantic Research Corporation on a project and got to see some of the other things they were doing including C-C composites for military applications. They braided the carbon fiber preforms and then used vapor deposition to build up the carbon matrix. The two applications I recall were rocket nozzles and submarine propellers. Like you said, very expensive. I am very interested in seeing your results.

It will be interesting to see if it can bind the graphite and also how fragile it is.

Neuport said:

Sounds like a good project. The carbon-carbon I am familiar with dates back to the 80's. I was working with fiber composite gurus from Drexel and Atlantic Research Corporation on a project and got to see some of the other things they were doing including C-C composites for military applications. They braided the carbon fiber preforms and then used vapor deposition to build up the carbon matrix. The two applications I recall were rocket nozzles and submarine propellers. Like you said, very expensive. I am very interested in seeing your results.

It will be interesting to see if it can bind the graphite and also how fragile it is.

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Thanks Neuport. It's good to see some input from some one with experience with real carbon-carbon.
Looking at the specsheet for the adhesive it looks like it is capable of bonding to graphite. It looks like the strength is roughly 1/3 to 1/2 of a good epoxy.

Getting the ratios right of everything is going to be interesting.

-Ted

tagerton said:

It's good to see some input from some one with experience with real carbon-carbon.

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I wouldn't say "experience" as much as exposure. My project related to braided medical textiles not composites. But in touring the facilities and talking with counterpart engineers I saw what they were doing with the c-c. I look forward to learning from the real experts and your experiments if it comes to that.

McMaster.com carries the 904 zirconia adhesive at $83 per pint tub. It's a paste. MSDS: https://www.mcmaster.com/#0668300-904-zirconia-adhesive-081011/=iqfa7e

What the heck ever happened to all those “super materials” that were patented within a few months of the development of Bucky-Balls?

By now Carbon-Carbon was supposed to be old hat.

Rocketjunkie said:

McMaster.com carries the 904 zirconia adhesive at $83 per pint tub. It's a paste. MSDS: https://www.mcmaster.com/#0668300-904-zirconia-adhesive-081011/=iqfa7e

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Good find. That's not too cheap, but I may have to get some anyways.


boomtube: Buckyballs, nanotubes, and other carbon allotropes would be fun to play with. If only they were easy to get...

-Ted

Edit: Well, you may be able to buy nanotubes on the internet.... https://www.nanoshel.com/nanoshel_c...roduct=COOH-FUNCTIONALIZED-MWCNT_COOH-MWCNT-1

No idea if that would work at all or be reasonably cheap. Cool none the less. Strength of 45 gPa :eyepop:
Of course the rated temperature stability is only up to 700c

Edit2: This one is $900 a gram. Ouch.
https://www.sigmaaldrich.com/catalog/product/aldrich/637351?lang=en&region=US

Just got an email from Cotronics. It looks like I want the 931 adhesive. It says it forms a pure graphite bond. Usable up to 5400 deg F. That's what I'm talking about!
https://www.cotronics.com/catalog/32 904- 931.pdf

Reinforced Carbon-Carbon is not simply graphite strengthened with carbon fibers. It is indeed very strong and heat resistant, but it is more like a ceramic than a composite, but much less brittle than most ceramics. Real RCC was used as the nose and leading edge tiles on the space shuttle, as well as some rocket nozzles, and RCC is difficult and very expensive to make. It is also used for commercial and military jet aircraft and race car brake rotors.

Taking graphite powder, chopped carbon fibers, and an ultra high temp adhesive and mix them together will not make RCC. Indeed the ultra high temperature adhesive suggested is actually ZrO2 (Zirconium Oxide, a ceramic). Carbon fibers and metal oxide pastes have been used to make ceramics and while another Cotronics adhesive for carbon furnaces is actually carbon, any alloying materials must be brought up to well over 2500 C, usually under pressure, for processing. Sorry to burst your bubble but making RCC or any advanced composite ceramics at home is not a possibility.

Fiber Materials, Inc. is an industry leading company producing high temperature materials, advanced composites, carbon and graphite insulation and carbon/carbon composite products. FMI has been doing so for more than 40 years, and also offers quartz based fiber and fabrics, ablative coatings, and an independent Energy Materials Testing Laboratory. Started in 1969 by an innovative and resourceful engineer, Fiber Materials, Inc. continues to progress as a corporation by researching, manufacturing and distributing advanced composite and high temperature materials for the defense, aerospace and commercial markets. FMI developed reinforced composites used in strategic missile systems and space reentry vehicle applications. Along with these advances, FMI manufactures felt and rigid carbonaceous insulation materials and Commercial Carbon Composites, a strong, lightweight and durable carbon matrix used in many commercial applications. In 1972, all operations were moved to a manufacturing and testing complex located in Biddeford, Maine. As of October 2011, Fiber Materials Inc. became a wholly owned subsidiary of GrafTech International, a publicly held company that is headquartered in Parma, Ohio. but will continue to operate as Fiber Materials Inc. To learn more about GrafTech, please visit [URL="https://www.graftech.com"]www.graftech.com. [/URL]

Follow the links above to find out how commercial high temperature materials are manufactured.

Bob

Have fun experimenting. I watched a episode of "How its Made" where they showed them making Ferrari brake rotors using a chopped carbon fiber mix and and then pressing it into a mold.

Tom can you give any insite to how your o3000 vulcan held up with your nozzle extender ?

AHansom said:

Have fun experimenting. I watched a episode of "How its Made" where they showed them making Ferrari brake rotors using a chopped carbon fiber mix and and then pressing it into a mold.

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The difficult part of making RCC is baking the material to extremely high temperatures, converting the binding adhesive into almost pure carbon - the graphite. It must then be heat soaked at these high temperatures for several days while carbon forming gasses - acetylene being the most common - are pumped through it, filling the voids that form during the conversion from binder to carbon and forming large graphite crystals, which is what makes it strong.

The only thing adding graphite powder to epoxy will achieve is to color the epoxy black. It might even improve it's insulation properties, by blocking IR radiation, but what it won't do is make RCC. It is a very specific material, and there is a reason it costs outragous amounts of money. Carbon-ceramic is used as much cheaper but similar alternative for the brakes in some sports cars (F-1 uses the real thing), costing only several thousand dollars per set of disks.

Nerull said:

The difficult part of making RCC is baking the material to extremely high temperatures, converting the binding adhesive into almost pure carbon - the graphite. It must then be heat soaked at these high temperatures for several days while carbon forming gasses - acetylene being the most common - are pumped through it, filling the voids that form during the conversion from binder to carbon and forming large graphite crystals, which is what makes it strong.

The only thing adding graphite powder to epoxy will achieve is to color the epoxy black. It might even improve it's insulation properties, by blocking IR radiation, but what it won't do is make RCC. It is a very specific material, and there is a reason it costs outragous amounts of money. Carbon-ceramic is used as much cheaper but similar alternative for the brakes in some sports cars (F-1 uses the real thing), costing only several thousand dollars per set of disks.

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Thanks for the info everyone.
I realize what I may be making is not a 'true' RCC. That is ok. But if I use something like the cotronics 931 adhesive, which forms nearly pure graphite, and I mix that with chopped carbon fibers (or even cloth) and more graphite, I feel like I will end up with something very similar to RCC. This adhesive only needs to cure at about 250 deg F, which is very doable. No high pressures needed, although pressing this material could add a lot of pressure.

I agree plain old epoxy wouldn't work very well. That looses strength well below 1000 F.

-Ted

tagerton said:

Thanks for the info everyone.
I realize what I may be making is not a 'true' RCC. That is ok. But if I use something like the cotronics 931 adhesive, which forms nearly pure graphite, and I mix that with chopped carbon fibers (or even cloth) and more graphite, I feel like I will end up with something very similar to RCC. This adhesive only needs to cure at about 250 deg F, which is very doable. No high pressures needed, although pressing this material could add a lot of pressure.

I agree plain old epoxy wouldn't work very well. That looses strength well below 1000 F.

-Ted

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Ted

The Cotronics carbon adhesive is for sticking graphite bricks together to prevent convective losses in a furnace. It's not for strength.

The traditional way of making RCC is to infuse a phenolic resin into a woven carbon weave preform, and then bring it to a very high temperature in a vacuum furnace or inert atmosphere furnace to pyrolyze the phenolic into graphite. The part is then cooled and reinfused with phenolic resin under pressure and reheated to pyrolyze the additional phenolic. It can be infused with a carbonizing gas to further increase the density.

The RCC manufacturing process is described in detail in the reference I provided in my previous post. When the first RCC materials were produced, the cost was about $10,000 per cubic inch! The costs have come down a lot today but there are still no shortcuts to making RCC. If there were they would be used industrially because the cost of making RCC is still very expensive and the aircraft industry would like to reduce the manufacturing cost by an order of magnitude or more.

I have more than casual knowledge about these materials. My company works in very high temperature exotic materials R&D. We made the highest temperature ceramic material available for use oxidizing environments (liners for scram jet engines). Your process to make RCC will not work, but it will still be very expensive to try it.

Bob

might not be what you had in mind but I think its interesting

https://www.youtube.com/watch?v=Q_3PebbkGpo

AHansom said:

might not be what you had in mind but I think its interesting

https://www.youtube.com/watch?v=Q_3PebbkGpo

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Yeah! Several days of processing at temperatures to 1,700 C (3,000 F) with a $100,000+ heated hydraulic press. Got everything in the basement. Not. And that's only for Silcone Carbide.

CC manufacturing needs even higher temperatures up to 2,800 C (5,000 F). A great reference on the processing is located at
https://www.ias.ac.in/sadhana/Pdf2003Apr/Pe1069.pdf

Bob

bobkrech said:

Reinforced Carbon-Carbon is not simply graphite strengthened with carbon fibers.

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As Bob has already explained, RCC is a VERY different thing than carbon-fiber-composite material.

I saw the manufacturing process for RCC back in the 70s at Vought. Trust me, you ain't gonna pull this one off in your oven at home.

Thanks for the input everyone.
This has been a very informative thread.

It sounds like my idea of carbon + graphite reinforced high temp composite may or may not work (with many leaning towards not). The only substantial con is the strength. This is a very important property of the material, but not necessarily a deal breaker.

How would the strength compare to plain graphite? That is the alternative in this case. Also maybe there are other resins that would be better? (It looks like the brake discs use a high temperature silicon carbide resin)

For rocket nozzles, it would be very good to be able to have a shaped inside and outside, (like the picture in the first post). This would usually mean using one material. Ideally I could make a nozzle out of this composite, either as a mold, machining, or a combination of the two. Alternatively, perhaps one could make a similar nozzle out of aluminum, then press this uncured high-temp composite into interior of the nozzle, forming a sort of thick coating. It's a long shot, but it could produce a sort of one-piece graphite-like inner liner to a nozzle that would otherwise not be possible. If you were to press it, it is possible to get fairly high temperatures and pressures, or at least up to the point of the casing material.

-Ted

tagerton said:

Thanks for the input everyone.
This has been a very informative thread.

It sounds like my idea of carbon + graphite reinforced high temp composite may or may not work (with many leaning towards not). The only substantial con is the strength. This is a very important property of the material, but not necessarily a deal breaker.

How would the strength compare to plain graphite? That is the alternative in this case. Also maybe there are other resins that would be better? (It looks like the brake discs use a high temperature silicon carbide resin)

For rocket nozzles, it would be very good to be able to have a shaped inside and outside, (like the picture in the first post). This would usually mean using one material. Ideally I could make a nozzle out of this composite, either as a mold, machining, or a combination of the two. Alternatively, perhaps one could make a similar nozzle out of aluminum, then press this uncured high-temp composite into interior of the nozzle, forming a sort of thick coating. It's a long shot, but it could produce a sort of one-piece graphite-like inner liner to a nozzle that would otherwise not be possible. If you were to press it, it is possible to get fairly high temperatures and pressures, or at least up to the point of the casing material.

-Ted

Click to expand...

Woven 4-D RCC nozzles

Example RCC motor assembly

Follow links for more info.

Bob

tagerton said:

Thanks for the input everyone.
This has been a very informative thread.

It sounds like my idea of carbon + graphite reinforced high temp composite may or may not work (with many leaning towards not). The only substantial con is the strength. This is a very important property of the material, but not necessarily a deal breaker.

How would the strength compare to plain graphite? That is the alternative in this case. Also maybe there are other resins that would be better? (It looks like the brake discs use a high temperature silicon carbide resin)

For rocket nozzles, it would be very good to be able to have a shaped inside and outside, (like the picture in the first post). This would usually mean using one material. Ideally I could make a nozzle out of this composite, either as a mold, machining, or a combination of the two. Alternatively, perhaps one could make a similar nozzle out of aluminum, then press this uncured high-temp composite into interior of the nozzle, forming a sort of thick coating. It's a long shot, but it could produce a sort of one-piece graphite-like inner liner to a nozzle that would otherwise not be possible. If you were to press it, it is possible to get fairly high temperatures and pressures, or at least up to the point of the casing material.

-Ted

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So if you want to make rocket nozzles, have you looked into inconel or any of the other superalloys? Inconel is commonly used for turbine components, espescially blades, due to its extreme hardness, temp resistence, and corrosion resistence. These properties make it ideal for use in rocket engines, also. It can be obtained from Mcmaster Carr, for something like $150 for 18in of 2in diameter rod. The downside is that it's very difficult to machine, and any mchining will result in severe work hardening. In industrial settings, it's usually cast into the rough shape, and then machined to the final shape. Not an attractive material for the hobbiest, but more attainable than RCC production in your basement.

RadManCF said:

So if you want to make rocket nozzles, have you looked into inconel or any of the other superalloys? Inconel is commonly used for turbine components, espescially blades, due to its extreme hardness, temp resistence, and corrosion resistence. These properties make it ideal for use in rocket engines, also. It can be obtained from Mcmaster Carr, for something like $150 for 18in of 2in diameter rod. The downside is that it's very difficult to machine, and any mchining will result in severe work hardening. In industrial settings, it's usually cast into the rough shape, and then machined to the final shape. Not an attractive material for the hobbiest, but more attainable than RCC production in your basement.

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Try ~$150 for 2" dia. x 3" from MMC! Inconel and other super alloys are used only in liquid motors that are regeneratively cooled.

Metals are not appropriate for any high performance solid motors because they oxidize and melt.

Injection molded phenolic resin nozzles have been the standard single use ablative nozzles for AT and CTI hobby rocket motors for decades. Kosdon, AMW, Loki, Gorilla and others have used inexpensive graphite for reusable hobby rocket motor nozzles. There is no need to reinvent the wheel. These materials work well and are cheap and easy to make or purchase.

Bob

bobkrech said:

Try ~$150 for 2" dia. x 3" from MMC! Inconel and other super alloys are used only in liquid motors that are regeneratively cooled.

Metals are not appropriate for any high performance solid motors because they oxidize and melt.

Injection molded phenolic resin nozzles have been the standard single use ablative nozzles for AT and CTI hobby rocket motors for decades. Kosdon, AMW, Loki, Gorilla and others have used inexpensive graphite for reusable hobby rocket motor nozzles. There is no need to reinvent the wheel. These materials work well and are cheap and easy to make or purchase.

Bob

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I would agree with you for the most part; my post was somewhat tounge in cheek. However, If he thinks reinventing the wheel could be fun, then more power to him.

3stoogesrocketry said:

Tom can you give any insite to how your o3000 vulcan held up with your nozzle extender ?

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I used the 2300 deg alumina ceramic. The motor was smoky sam so relatively cool and the insulation was not melted at all.

RadManCF said:

So if you want to make rocket nozzles, have you looked into inconel or any of the other superalloys? Inconel is commonly used for turbine components, espescially blades, due to its extreme hardness, temp resistence, and corrosion resistence. These properties make it ideal for use in rocket engines, also. It can be obtained from Mcmaster Carr, for something like $150 for 18in of 2in diameter rod. The downside is that it's very difficult to machine, and any mchining will result in severe work hardening. In industrial settings, it's usually cast into the rough shape, and then machined to the final shape. Not an attractive material for the hobbiest, but more attainable than RCC production in your basement.

Click to expand...

I've looked into Inconel a little bit. Two issues: one I'm not sure I'd be allowed to fly those at the Tripoli research days due to their limitations on materials. (Apparently steel nozzles are banned). Two: I think machining it would be prohibitively difficult and I would probably ruin either the tools or the material or both. I would be machining a very large amount of it off, which could be very challenging. I do have access to some decent carbide tipped lathe tools though.

I'll keep that possibility in mind. It would be awesome to have an Inconnel nozzle with some sort of ceramic or my (not really C-C) liner.

So I do agree all this sounds a bit crazy, like I am reinventing the wheel. To me, the main reason to do the reinforced carbon-graphite composite is to make a stronger and/or lighter nozzle. (although realistically, saving 100 grams on a nozzle isn't going to make that big of a difference, most of this is because I think it's fun and interesting) Most likely I will be doing the standard graphite insert into an aluminum nozzle. Although I just think it would be really cool and interesting to try something new, especially for the hobbyist level.

One thing to note is I do go to an engineering university, and I'm good at convincing people to let me use their expensive machines. We have a sizable materials science department where I may be able to get access to high pressure / temperature processing equipment if needed.

-Ted

tagerton said:

I've looked into Inconel a little bit. Two issues: one I'm not sure I'd be allowed to fly those at the Tripoli research days due to their limitations on materials. (Apparently steel nozzles are banned). Two: I think machining it would be prohibitively difficult and I would probably ruin either the tools or the material or both. I would be machining a very large amount of it off, which could be very challenging. I do have access to some decent carbide tipped lathe tools though.

I'll keep that possibility in mind. It would be awesome to have an Inconnel nozzle with some sort of ceramic or my (not really C-C) liner.

So I do agree all this sounds a bit crazy, like I am reinventing the wheel. To me, the main reason to do the reinforced carbon-graphite composite is to make a stronger and/or lighter nozzle. (although realistically, saving 100 grams on a nozzle isn't going to make that big of a difference, most of this is because I think it's fun and interesting) Most likely I will be doing the standard graphite insert into an aluminum nozzle. Although I just think it would be really cool and interesting to try something new, especially for the hobbyist level.

One thing to note is I do go to an engineering university, and I'm good at convincing people to let me use their expensive machines. We have a sizable materials science department where I may be able to get access to high pressure / temperature processing equipment if needed.

-Ted

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I forgot to mention, Inconel is also commonly machined by grinding, which avoids the problems of work hardening.

RadManCF said:

I forgot to mention, Inconel is also commonly machined by grinding, which avoids the problems of work hardening.

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That's good info to know. That sounds like a difficult way to bore out a nozzle.

boomtube said:

What the heck ever happened to all those “super materials” that were patented within a few months of the development of Bucky-Balls?

By now Carbon-Carbon was supposed to be old hat.

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Don't worry, I think that great times for graphene, fullerenes and other nanomaterials are comming soon. It wasn't such a large boom as everybody expected but still the development shifted. Its not only an interesting lab experiment. There are all companies dedicated to produce nanomaterials on industrial scale (for example this one). Because of this accessibility, there are many different companies experimenting with enhancing of their products with these materials, from medical to sport equipment.

"I forgot to mention, Inconel is also commonly machined by grinding, which avoids the problems of work hardening."

I didn't know that. Thanks for the info!

arra77 said:

Don't worry, I think that great times for graphene, fullerenes and other nanomaterials are comming soon. It wasn't such a large boom as everybody expected but still the development shifted. Its not only an interesting lab experiment. There are all companies dedicated to produce nanomaterials on industrial scale (for example this one). Because of this accessibility, there are many different companies experimenting with enhancing of their products with these materials, from medical to sport equipment.

Click to expand...

Travisio said:

"I forgot to mention, Inconel is also commonly machined by grinding, which avoids the problems of work hardening."

I didn't know that. Thanks for the info!

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Welcome to TRF! Are you aware that you are resurrecting a ( very interesting ) thread from 2012?