In article <
[email protected]>,
Rick Onanian <
[email protected]> wrote:
> On Tue, 16 Dec 2003 20:04:35 -0500, "David L. Johnson" <
[email protected]> wrote:
> >On Tue, 16 Dec 2003 15:27:41 +0000, David Kerber wrote:
> >> On a serious note, I think Ti would make lousy razor blades, because I don't think it's hard
> >> enough to hold a good edge. If any of you are familiar with the metallurgy of Ti, could you
> >> confirm or deny that?
> >
> >Of course that is right. The razor blades are probably titanium _colored_, or at best plated (if
> >that is possible), but not made out of it.
>
> Today in Wal-Mart, buying cat litter and frozen pizza in bulk, I walked past electric razors
> labeled titanium, and thought of this thread. Just now, I googled and got this:
>
http://www.kohls.com/products/product_page_vanilla0.jsp?PRODUCT%3C%3Eprd_id=59 940127
>
> Yup, titanium-coated blades.
>
> >Titanium has a mystical reputation as bring harder and stronger than steel, and lighter than
> >aluminum, when in fact it is none of the above.
>
> Titanium is magic, didn't you know that?
>
> My cat just meowed as I was typing that last sentence.
> --
> Rick Onanian
I'm a metallurgist and I love titanium, but it gets used inappropriately all the time.
Most titanium isn't particularly hard and certainly isn't used for cutting. Good old alloy steel is
the best metal for that; some stainless steels are OK and they don't rust, so they're used for
knives too:
http://www.timken.com/products/specialtysteel/engineering/tech_info/html/
Knife%20Steels.htm
A lot of cutting edges, though, are coated with titanium nitride, which is a **ceramic** (remember
the name of this thread?). This makes a hard, low-friction cutting edge and is, in fact, what's on
those misleadingly-labelled "titanium" shavers (Remington just got whacked about that:
http://iavbbs.com/gflinn/news.htm). It's not clear to me whether a titanium nitride coating is
helpful when cutting whiskers.
I would only use ceramic bearings on a bike if the original bearings tended to get red hot in use.
This has, as far as I know, never happened to me.