I once thought that the Tenifer process was proprietary to Glock, but Taurus is advertising a “Tennifer” finish on some of their firearms:
http://www.taurususa.com/products/product-details.cfm?id=602&category=Pistol#
Is it a case of semantics (“Tenifer” vs Tennifer")?
Tenifer is a trademarked name for a process. It’s proprietary, but not to Glock. The generic name is “carbonitride”
Glock uses the process, but does not own it.
Thanks for the clarification. Just that (as far as I can recall) this is the first time I’ve heard anyone other than Glock using that particular name on their products.
Glock is probably the most visible user of tenifer, but not the only one. They may somehow own it, but that doesn’t mean they wouldn’t license it elsewhere.
If you do a little research you’ll find other companies/products that do use it.
People that have machined on glock slides claim that tenifer is hard to cut through. 
It seems to rub off from holster wear though.
It’s my understanding that the hard Tenifer finish is applied to the metal and then the black final coat is applied over that. So the blueing is just rubbing off but the Tenifer is unaffected.
The older black oxide finish and the newer black coating that show wear are not the tenifer finish. They are just a coating over the finish.
Ah! I see.
Having a newer Glock 21 (2007 manufacture), what was/is the difference between the older and newer finishes?
As I understand it, the carbonitriding process is a metal treatment, as opposed to a finish. The slides are treated in a heated solution then quenched. Once they are cooled the outer few thousands of an inch are extremely hard (around 60 RC) while the inner core of the slides are much more ductile. This allows the slides to have a very hard, wear resistant surface without being brittle or prone to cracks.
The black finish that we see is parkerizing or a baked-on paint type finish. The finish we see may come off, but the metal treatment remains.
I dont’ know for sure, but I believe the older guns were parkerized while the new ones have a baked on style finish. That’s just the finish. Under the black stuff, the metal treatment is the same.
I always thought that “Tenifer” was the name of the guy in the factory who pushed the button of the machine that applied the “carbonitride” finish…
And since he worked for Glock, only they could have a “Tenifer” finish on their guns… Now if his cousin “Tennifer” who is a master button pusher by all acounts, has been employed Taurus to push the button on their “carbonitride” finish machine , well then all bets are off…
B
P.S. What a wonderful modern age we live in…
The reason Tenifer isn’t more common in the U.S. is because some of the specific chemicals used are highly restricted here. They’re not restricted in Austria (Glock) or Brazil (Taurus). A very similar treatment, Melonite, is available in the U.S. and is used by many different companies under that or other trade names.
As others have already explained, the Tenifer/Melonite process treats the surface of the steel to make it harder and less porous, providing both corrosion and scratch resistance. Those processes do not change the color of the metal. After the Tenifer/Melonite process, different companies apply different finishes to provide the color (which is usually black, but does not have to be). This can further provide a degree of corrosion resistance, lubricity, etc. depending on the specific finish chosen.
i’m having a 1911 checkered/re-sighted/melonited at Drake’s Gun Works as we speak. he specifically said to do all frame machining before meloniting, as the surface gets harder and consequently harder to machine after the treatment.
That is why you don’t see a lot of carburizing in the industry. It’s a similar process to carbonitriding but it’s done at a higher temp, which can cause warpage.
Walther and Steyr also use Tennifer on their newer guns (P99, PPS, etc.)
Tennifer uses a very high amount of cyanic acid which is why it is so heavily controlled and is the chief difference between it and melonite.
We have something in common- he’ll be doing my gun soon also.
Post pics in the 1911 thread when its done.
Melonite/Tenifer is more of a surface “treatment” rather than a finish.
I have also heard that because of the high temps, there are certain parts you don’t want to mess around treating.
^i had a stainless first gen Kimber from their custom shop that shot WAY too good to let go, yet was way too pimp to actually use. so i settled on melonite. i’ll use it for training and for USPSA Single Stack 
Tenifer is a trademarked process. HK’s HE process is supposedly a knock off of Tenifer as well.
It does have a color too. The color is just so close to steel you can’t tell. If you cut a Glock slide in half you could probably see a difference.