Aluminium Brake Rotors

[Superfumi]

I heard woolongong ran these last year and used some process to harden the surface. Does anyone know about this or where I can find out more?

Cheers

[Superfumi]

I heard woolongong ran these last year and used some process to harden the surface. Does anyone know about this or where I can find out more?

Cheers

[woollymoof]

Either the rotors were coated with some ceramic or they were ceramic impregnated, that is with an aluminium matrix. Hell on pads, and on the tooling when machining. Give your local aluminium supplier a call, they would know more than I would.

[Michael Jones]

I believe Carroll Smith commented on this very issue, not being a fan of Al rotors in general but being convinced that ther particular implementation was good...can't remeber the comments verbatim though but if you have either the mp3 or transcript of his final design talk you'll find out something there.

---
Cornell Racing
http://fsae.mae.cornell.edu

[ben]

At Birmingham we use an aluminium MMC disc cast by New Pro and treated by Crompton Technology Group (CTG) using their Keronite surface conversion process.

I think the judges prefer alumnium to have some form of coating be it plasma or ceramic. I think what they really hate is uncoated Al discs.

Ben

[Al]

Monash used Aluminium rotors at the front on both our 2001 and 2002 cars. The 2001 car had a copper/stainless coating, while the 2002 car had a ceramic coating. We chose the ceramic coating in 2002 to overcome the significant warping that came about when applying the copper/stainless coating in 2001. I believe Wollongong used a similar coating in 2001.

The ceramic coating was applied in a layer around 0.25mm ish thick meaning low warping. The major problem with a ceramic coating is the thermal expansion differential between it and the underlying Aluminium. As you would expect ceramic doesn't expand much while Ally does. This isn't really a huge issue as SAE tracks don't require big stop after big stop.

Overall our 240mmx6mm discs weighed 620g while our steel back-ups weighed 1.3kg just for the friction surface. It's a good way to save significant weight, if you can find someone to coat the discs for you. Our guys took 5 months!!

We somehow managed to win the PBR brake award at the 2002 competition so the judges must have thought the discs were okay.

Hope that helps.

[ben]

The reason we use Keronite (aside from 2 alumni who work there) is that it isn't a coating, but a surface conversion process. This is far more durable and we don't get any warping problems.

Ben

[J. Cheng]

What about pad material? I used Al MMC rotors a few years back on my AMod car but the pads (supplied by the rotor company) kept leaving a deposit coating (black in color) on the rotor surface. Braking performance dropped substantially with usage.

What were the problems experienced with un-coated Al discs if any?

Joe

[Nigel Lavers]

HEre at the U of Alberta we coated our front and rear disks with a chromium carbide matrix (0.005" thick). It's an super high velocity thermal coating that has a bond strength near 80,000 psi. The brinell hardness is quite high, and the wear properties are phenomenal---the supplier (Western Hard Chrome Ltd.) has coated his Camaro the same way and has noticed no cracking or wear after a few years of driving.

It won't thermally expand the same as the aluminum underneath (as mentioned already), but that isn't a huge problem for FSAE.

The only problem is trying to throw that into the cost report---very expensive stuff.

We didn't get a chance to talk to the BRP guys for the braking award last year, but we will this year!

Nigel

[Spec]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Michael Jones:
I believe Carroll Smith commented on this very issue, not being a fan of Al rotors in general but being convinced that ther particular implementation was good...can't remeber the comments verbatim though<HR></BLOCKQUOTE>

Correct, if I remember the comment correctly, he was very concerned about warping. Although I believe if a team is using a metal matrix or a coating to deal with that issue... all should go well.

Steve