Titatinum tools

[claude]

Is there someone out there who can clarify a mystery for me. I have just bought all sorts of titanium drill bits and have other tools that they say contain titanium. I don't get it, working on a titanium aircraft part with a normal chrome molly tool will destroy that titanium part. So how can they alloy or coat a drill bit that won't react to itself or to the part you are working on at the molecular level? The only explanation I can think of right now is that the titanium they mention is bull and is just a fancy colored coating.

The tools work well enough but I am a very curious individual.

Claude Montreal

[Malcolm Hoar]

Titanium by itself isn't especially hard.

But it can bring many desirable properties to other metals when combined into an alloy (or used as part of a coating).

General reading on titanium:

[hallerb]

my experience those titanium drill bits are a waste of money, the gold color looks nice but they actually dull faster.

its a marketing ploy, and a good friend with a machine shop reached the exact same conclusion indenpendent of mine.

[RicodJour]

It is not a titanium coating. It is a titanium _oxide_ coating. Oxides are frequently far harder than the principal element. Aluminum oxide, one of the softer metals, is used as an abrasive and is very hard.

R

[DT]

What do you work on titanium parts with? I worked with plenty of extremely highly stressed titanium parts at NASA and we used ordinary tools and bolts. And tools aren't chrome-moly anyway.

-- Dennis

[Jeff]

Bits are coated after sharpening with a thin layer of titanium nitride which is a hard material.

see

for more detail.

[RicodJour]

Hmmm. Thanks for posting that link. I'd posted earlier about titanium oxide coating, which is commonly used on knives - not sure why I confused the two in my mind. Titanium oxide is hard, titanium nitride is much harder. Thanks for setting the record straight, Jeff.

R

[Jim Yanik]

"RicodJour" wrote in news: [e-mail]:

WRONG;it's titanium NITRIDE. Almost as hard as diamond,excellent wear resistance.

titanium oxide is a pigment used in white paint.

Strange,because aluminum oxide forms on any piece of bare aluminum exposed to oxygen or ordinary air. And carbon steel drill bits drill it easily. Of course,it IS harder than WOOD,so it's used for cheaper sandpaper. It's not very hard compared to other abrasives.

[Jim Yanik]

"RicodJour" wrote in news: [e-mail]:

I've never heard of titanium oxide being used on knives for a coating. Unless it's white paint. ;-) I have heard of TiN being used on knives,for the same reason it's used on drills.It also dresses them up nice.You can even buy fancy dinner cutlery with TiN coating;it looks like gold plate,but does not wear like gold plate.

It's deposited by vapor deposition;a plate of Ti is inside a vacuum chamber pressurized with nitrogen (at ~400degF,IIRC),and an electric arc is discharged to the sacrificial Ti plate,vaporizing it and combining it with the Nitrogen to form TiN,which falls onto the metallic items placed in the chamber,plating them. Plating thickness is determined by arc current and time.

[RicodJour]

innews: [e-mail]:

Jeff already pointed that out, and I already thanked him for pointing it out.

The oxidation of aluminum is not the same as aluminum oxide. If I dusted diamond powder on your cereal, you'd never know it. If there were a small diamond in your cereal, you'd break a tooth. Rubies and sapphires are aluminum oxide. Them's plenty hard, chief!

Aluminum oxide sandpaper is not cheap, it's appropriate. The "cheaper" grades are flint and garnet papers, and they're appropriate for other uses. That's a whole 'nother thread, so let's not get into that in this one.

R

[RicodJour]

See? That's where I thanked Jeff. He just beat you to it!

You've seen it, I'm sure. The coating gives a rainbow color and can come from heat treating titanium or using a titanium oxide coating on steel (for knives and such).

I know the white paint pigment as titanium dioxide, which also seems to be known as titanium oxide...just to confuse people. There're titanium oxides, dioxides and trioxides. I'm about oxided out of here!

The titanium oxide coating is also vapor deposited.

Seems like we're all learning something in this thread. One of the reasons I love newsgroups.

R