I was browsing DPMS' toybox today, and they're selling a B/BC assembly that is coated in Titanium Nitride.  I am a Criminology major here and have no clue what that stuff is.  Anyone hear of it and/or know what it is?  

Since the price on it was $20 more than a chrome b/bc, I assume this is supposed to be better than chrome?  If so, in what way?  Or is this just the fancy new thing to separate me from my money?

It's a surface treatment that involves diffusing titanium and nitrogen into the surface of steel to improve surface hardness and lubricity.  It's done in a sealed oven at high temperature with the deposition materials vaporized in the oven's atmosphere.

When you buy the gold TiN drill bits, that's what it is.  Done right, it can really toughen up steel on the surface and make it highly wear-resistant.  It's done on aircraft crankshafts and (I'm told) Honda does or used to do it to theirs as well.

I'm not a metallurgist, but that's my best understanding of it, anyway.  Hope that helps.

Oh, and technical stuff aside, I'm not sure that it's really worthwhile on an AR bolt and I doubt that it would be a significant improvement over chrome.  Personally, I don't like shiny stuff on my guns and the stock bolt carriers work perfectly fine.  Neat to have, but I'd be shocked if anyone could objectively demonstrate any tangible benefits from it on an AR bolt/carrier.  If I really wanted extra wear resistance, I'd pick TiN over chrome, though.

Titanium nitride is fine for cutting tools, but its a gimmik in ARs.  It has no advantage over chrome and has the disadvantage of looking cheesy.  Might look good and be useful on a gold plated AR or something like that.

Here's my repeated answer to this repeated question.  It's updated every once in a while but is current as of today.  I've got guns from almost all of the suppliers and can't think of one that I haven't fired except for some of the wierd very early ones.

The top two are close:

Colt.  Whatever you like or dislike about this company, it's still got the pony on the side and is the only company that can sell rifles that have parts based on the government prints.  It's headed by a retired Marine Lieutenant General who's shaking things up there.  Their weak point is military business that weakens their focus on private buyers but hell, this is war.

ArmaLite.  OK, ArmaLite is only headed by a retired Army Lieutenant Colonel, but he was an ordnance officer so that counts for something.  He was a cop too.  Their strong point is lifetime warranty, great engineering, and a string of new products.  They've got 5 rifles (10, 15, 180, and the very neat bolt action AR-30 and AR-50).  Quality is very high.  Their weak point is supply.  It's hard to find an ArmaLite.  Word is that export military sales are cutting into supplies but hell, this is war.  

Buishmaster.  Their advantage is good supply of good guns.  Not great guns.  Their weak poiint is occasional oopses like purple rifles.

Olympic.  OK guns.  Average quality.

DPMS.  Good guys.  Their specialty is decent guns at low price.  

All the others.  Surplus guy, hobbyists, ex-emplolyees of other companies, and parts manufactures who learned that it only takes a little more effort to get a license, make a couple changes to brag about big "improvements" and "imagination" and then sell guns.  Watch for two things; massive copying and very uneaven quality.  The general problem at this end of the market is that they buy parts from a pool of suppliers and build good guns one week and lousy ones the next.

I rate ArmaLite as my favorite but support the old saying "Stick with ABC:  ArmaLite, Bushmaster, and colt."

TiN sucks in the GUN realm.

LotBoy's TiN carrier rusted bad from a swamp cooler.  Conventional AR parts finish have not given him a problem.

But do you get extra pimp points for a gold bolt carrier?

Gold is always better than silver

only if you have ivory furniture on the rifle.

I like blammo's explanation of it. It does reduce initial surface friction which is why high end motorcycle companies use it in their suspension componets(Ducati does this on their high end bikes). I think it's a case of if it ain't broke dont fix it but if it's only 25 more bucks and your going chrome anyway I would go for it. I think the gold bolt would look cool against all that evil black anyway!