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I have seen that ceramics take a lot of heat to melt (3240º F). So, I'm wondering, why aren't ceramics used as the compressor levels in turbines? Is there something to do with the strain? or is ceramic too heavy? Is it something to do with the way the crystals align?

DeltaLima
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Nicholas
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    Related: What material is used to make the hot sections of jet engines?. Ceramic would be used in the hot section, not in the compressor section. – mins Dec 08 '16 at 21:22
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    And also Why are aircraft turbine blades made of nickel alloys?, and ceramic matrix composites. – fooot Dec 08 '16 at 21:23
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    @fooot I see. Thanks for the help. However, suppose ceramics were used not only for the hot section. For example, how about the exhaust nozzles – Nicholas Dec 08 '16 at 21:25
  • Suppose there were an ignition source in the compression levels. Should a ceramic be used then? – Nicholas Dec 08 '16 at 21:27
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    The exhaust area is not really heat limited, nickel or titanium alloys do just fine. Ceramic is brittle so not well suited in most applications. CMC is still fairly new and may make more cost sense in the future. There would typically not be any ignition in the compressor sections, but anywhere handling ignition gases, like the turbine, would be limited by heat and thus benefit from ceramics. – fooot Dec 08 '16 at 21:33
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    @fooot Sorry. I should explain a little. The reason I'm asking is because I am creating an aircraft, and I'm looking for materials that will survive under the heat of a full jet fuel ignition. Since most turbines don't ignite, I need to look for more durable materials for my engine, and I'm trying to find whether ceramics would work for my purposes. I guess not. – Nicholas Dec 08 '16 at 21:41
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    Plain ceramics, not really. But the ceramic composites I linked to are starting to be used in turbines and they have weight and temperature benefits. – fooot Dec 08 '16 at 21:49
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    @mins I'm planning on using the compressors AS the combustion chamber. Right after(or in) the last high pressure section, I would set sparkplugs or another ignition source to light the fuel on fire, which should give a thrust boost. – Nicholas Dec 08 '16 at 21:53
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    @Nicholas there is a good reason all the experienced turbine manufacturers (and anyone who understands them) don't do combustion in the compressor. I suggest you go think why that is. – Notts90 Dec 09 '16 at 08:00
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    On the other hand, @Notts90, sometimes great breakthroughs come from those who go against the grain. (To be honest, I have no idea why combustion isn't done in the compressor, but I can think of a couple of reasons...) – FreeMan Dec 09 '16 at 20:22
  • @mins if the combustion was done before the last stage of the compressor what would be the point of any additional stages providing further compression? The additional stages would be redundant, you want turbines after combustion to recover energy. On top of that making components heat resistant adds a lot of weight. You want to have to do that to as little as possible. – Notts90 Dec 10 '16 at 10:02
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    @mins apologies, it's early here and brain hasn't fully engaged. – Notts90 Dec 10 '16 at 10:08

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Ceramic materials are starting to be used in jet engines. E.g. the LEAP-1A is using a few ceramic matrix composite in the high pressure turbine. (http://aviationweek.com/mro/ceramic-composites-enter-service). Future designs will likely expand the use of CMCs (e.g. http://www.geaviation.com/press/ge90/ge90_20150303.html)

Daniel K
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These highly desirable properties of ceramics have as yet been largely disregarded, due to the perceived low toughness and brittle failure demonstrated by traditional ceramic strength.

Ankit Aryal
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