Let's not get confused with terminology Subject matter Teflon.

 

Teflon

The name "Teflon" conjures up immediately Teflon coated cookware. Nowadays many other metal objects are "Teflon coated" for either aesthetic reasons or technical purposes. 

However, these coatings are not exactly the same as the machinable plastic (virgin unfilled)  known as Teflon PTFE (Polytetrafluoroethylene). A naturally white (in the un dyed state), soft, low friction plastic, resistant to heat and chemical attack by all but the most aggressive compounds such as Fluorine gas. It has been in use in the laboratory workspace for a great many years for a myriad of things required to be heat and chemical resistant and also in high temperature high voltage electrical insulators within high voltage tanks.

Polytetrafluoroethylene

otherwise known as:

Poly (1,1,2, 2-tetrafluoroethylene)

Where "n" are the number of subunits

This  is "pure" form of Teflon as it will not bind to metal in this form.

Now, as I will mention the word "Teflon" here many times it will be in reference to any chlorinated fluorocarbon which has been applied to the metal surface via some sort of spray painting followed by oven baking to finalise adhesion to the metal surface and also to produce a homogenous polymer finish to the surface in question. Remembering "Teflon" is simply a trade name which can be addressed to numerous  fluorocarbon based products.

So let's talk about the features of coating a blade with a Teflon type coating. The first thing which comes to mind is the reduction of friction when cutting, particularly man made objects such as plastics and rubbers. 

For example:

Trying to puncture a tire will go horribly wrong if one can not extract their tool in a hurry nor for that matter insert it to begin with. A Teflon coating on a knife blade will certainly aid in this sort of operation.

Many materials (man made) will not stick permanently to the surface of such a coating and can thus be easily removed either by simply wiping, if no water (as a common solvent) is available or  simply using water, or a mild solvent or detergent. 

 Since  most Teflon coatings are proprietary and by default these chemical formulations and technical data for application is not available to the end users, therefore, it is not possible to determine the full chemical resistivity  range, however it's probably safe to say that whatever chemical one can throw at such coatings, they will be resistant against such attack (with the exception of extremely aggressive compounds or gases, as mentioned above . 

Since these teflon type coatings can be available in many colours, this is a huge bonus again for a military knife where the coating must also function as an anti- glare coating so as not to reveal your location.

Good Teflon coatings are exceptionally strong and resistant to abrasion and more importantly impact forces. A good coating must also resist removal from the metal surface. Finally a good coating will help to slow the effects of corrosion if that coating is applied to a semi stainless steel or even stainless steels which have been heat treated to above HRC 58 as these types of steels in general will loose some of their corrosion resistance the less Chromium there is in solid solution. ie if Chromium is tied up in carbide formation then there will simply be less functioning in corrosion protection. Speaking of corrosion protection even 8% Cr will help to provide corrosion protection (for uncoated blades). Not to mention if the surface finish is smooth and free of defects, even a mirror finish will always be the better option for corrosion resistance.

@BCT