MFG info on PCCB
11-18-2003, 04:27 PM
#1
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MFG info on PCCB
Those of you with PCCB might be interested in the claims made by the company that makes the components for them...
http://www.sglcarbon.com/sgl_t/brakedisc/index.html#
click on the flash demo for carbon-ceramic automotive discs. They seem to promise the moon...
http://www.sglcarbon.com/sgl_t/brakedisc/index.html#
click on the flash demo for carbon-ceramic automotive discs. They seem to promise the moon...
11-18-2003, 04:32 PM
#2
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more interesting claims...
http://www.autointell.com/news-2000-...r-05-00-p5.htm
and here's a PDF that gives more information on SIGRASIC which apparently is the material that the brakes are made out of. Perhaps our chemist Hubert can comment more after reading some of this material...
http://www.sglcarbon.com/sgl_t/indus...sigrasic_e.pdf
http://www.autointell.com/news-2000-...r-05-00-p5.htm
and here's a PDF that gives more information on SIGRASIC which apparently is the material that the brakes are made out of. Perhaps our chemist Hubert can comment more after reading some of this material...
http://www.sglcarbon.com/sgl_t/indus...sigrasic_e.pdf
11-18-2003, 07:05 PM
#3
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Bob:
I read the material you provided. The rotors are a carbon fiber weave that reinforces a Silicon Carbide matrix; i.e., CSiC. Silicon carbides have long been implimented in industry as a very hard , and abrasive material for drilling, surface abrasions, silicon chip etching, etc.
However, becuase the "generic" industrial grade material is impure, it has an operational temp. ceiling of 1000 degrees C.
Above that it becomes unstable and begins to act as a thermal conductor and a semiconducting material. At 1200 degrees C it begins to oxidize (like I stated), but if the surface is allowed to cool (relativly) the oxidation is slowed by the formation of a surface coating of silicon dioxide, but if the temps remain elevated the oxidation front propgates through the material until the oxidizing agent (incoming oxygen) consumes the reducing agent (the disk material). The reuslt is the dusting/flaking of the disk; akin to chips of rusted metal.
What I believe happens is that the pads overheat, and crumble leading to an abrasion of the rotors. If the pads stay hot, the temps remain in the oxidizing range, and with the leading edge of the disk open to incoming oxygen, the oxidation takes place at a rapid rate. Resulting in the destruction of the rotor.
That's my hypothesis.
Regards, Hubert.
I read the material you provided. The rotors are a carbon fiber weave that reinforces a Silicon Carbide matrix; i.e., CSiC. Silicon carbides have long been implimented in industry as a very hard , and abrasive material for drilling, surface abrasions, silicon chip etching, etc.
However, becuase the "generic" industrial grade material is impure, it has an operational temp. ceiling of 1000 degrees C.
Above that it becomes unstable and begins to act as a thermal conductor and a semiconducting material. At 1200 degrees C it begins to oxidize (like I stated), but if the surface is allowed to cool (relativly) the oxidation is slowed by the formation of a surface coating of silicon dioxide, but if the temps remain elevated the oxidation front propgates through the material until the oxidizing agent (incoming oxygen) consumes the reducing agent (the disk material). The reuslt is the dusting/flaking of the disk; akin to chips of rusted metal.
What I believe happens is that the pads overheat, and crumble leading to an abrasion of the rotors. If the pads stay hot, the temps remain in the oxidizing range, and with the leading edge of the disk open to incoming oxygen, the oxidation takes place at a rapid rate. Resulting in the destruction of the rotor.
That's my hypothesis.
Regards, Hubert.
11-18-2003, 09:54 PM
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Interesting perspective, thanks for the comments. So are you saying that they are incorrect in their assertion that it has high thermal stability to 1350 degrees C or do you think maybe they are not using the generic industrial material?
11-18-2003, 10:08 PM
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Bob:
Per page 3 of the pdf file you furnished, they state "... with service temperatures up to about 1350C..."
I'm not saying they're incorrect, or purporting false data, but without a defined std. dev. of service temps v. component failure, I don't know what "up to about" is, quantitativly.
Either way, @ and above 1250C the conditions favor the oxidation of the material. And, while they may have proprietary formulation recipes, the "generic" CSiC carbides and material used thoughout industry have op. ceilings @ 1000C, and failure comes quickly after. Therefore, based on general empirical data, I'd say that it's more than plausible to assume that the chemical charactaristics of this SiC compound is comprable to other SiC applications.
Lastly (and I edited the post to include this), these SiC at high temps (and with greater purities) actually act as insulators, so heat build up in these materials (past the op ceiling) is very , very fast.
Regards, Hubert.
Per page 3 of the pdf file you furnished, they state "... with service temperatures up to about 1350C..."
I'm not saying they're incorrect, or purporting false data, but without a defined std. dev. of service temps v. component failure, I don't know what "up to about" is, quantitativly.
Either way, @ and above 1250C the conditions favor the oxidation of the material. And, while they may have proprietary formulation recipes, the "generic" CSiC carbides and material used thoughout industry have op. ceilings @ 1000C, and failure comes quickly after. Therefore, based on general empirical data, I'd say that it's more than plausible to assume that the chemical charactaristics of this SiC compound is comprable to other SiC applications.
Lastly (and I edited the post to include this), these SiC at high temps (and with greater purities) actually act as insulators, so heat build up in these materials (past the op ceiling) is very , very fast.
Regards, Hubert.
11-18-2003, 10:21 PM
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Gotcha... I was reading column 1 in the same page that made a more definite sounding statement of "high thermal stability up to 1350". Your hypothesis makes logical sense to me.
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11-18-2003, 11:03 PM
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The moral is....avoid situations that require overbraking. This explains why the CGTs had no evident problems even though they carried some incredible speeds around the track and scrubbed it off in short order.
Maybe Hubert would like to explain how exponential heal build up occurs with this material versus steel for instance?
Maybe Hubert would like to explain how exponential heal build up occurs with this material versus steel for instance?
Last edited by PogueMoHone; 11-19-2003 at 04:33 PM.
11-18-2003, 11:09 PM
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I'd like to hear a more scientific explanation there too. I've made some assumptions myself about iron being a much more forgiving material and also people being much more tolerant of damaged steel rotors - for example, I've heard of a lot of people warping their rotors...
11-19-2003, 12:24 PM
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their website says referring to the porsche brake:
"Carbon-Ceramic brake discs are designed to last the entire lifetime of a car. "
if bill clinton was parsing that sentence, would he say "are designed" does not mean "will"?
"Carbon-Ceramic brake discs are designed to last the entire lifetime of a car. "
if bill clinton was parsing that sentence, would he say "are designed" does not mean "will"?