Since 2006, Springfield has been shipping a large portion of their pistols treated in an anti-corrosion process described as Melonite. Unlike Duracoat, cerakote, and others, Melonite is not a spray-on or baked-on coating. It is not paint. Like hard chroming or nickel treatments, it is a much more intensive but is almost 20-times as strong as those legacy processes. Melonite is a very hard finish that is produced by a controlled chemical reaction and here at XD Forums we thought you should know just what it is.
Don't mistake the finish for the mineral!
First of all, there is a mineral, chemical formula NiTe2, that is called Melonite. Geologists know this soft flaky trigonal crystal as a telluride of about 18% nickel (Ni) mixed with a telluride ion (Te2) and is found in nickel mining. This nonmagnetic mineral is not actually used in the making of Melonite finishes, so do not confuse the process with the metal. They are two completely different things.
The Burlington Melonite process is applied in a salt bath ferritic nitrocarburizing. What this means is that a mix of nitrogen, oxygen, and carbon are simultaneously forced into the steel that is being treated. These three elements bind and produce a single layer that impregnates the steel much deeper than traditional gun bluing or chroming which only covers the surface layer. Once cured it becomes anywhere from a Rockwell Hardness of 55-65, which if you know anything about the steel used in knives is pretty hard. The process generally only adds .0005-inches (that's five ten-thousandths of an inch) of dimension to treated metals which in turn does not require any additional grinding to remove as it's within the design specs of the firearm. As the top the layer of the process is exposed to oxygen, its turns a natural uniform dark black color.
Not only XD but also Smith and Wesson, Steyr, and Walther have turned to the Melonite process to give their polymer-framed guns a dose of real world anti-corrosion finish. Custom rifle makers also use it for barrels and actions subject to extreme hunting conditions.
Other uses for Melonite finishing
Besides, in firearms of all sorts, Melonite is used commonly in several different industries that require high surface wear resistance to prevent corrosion and heat damage. This includes being used in dies for molding and tooling, automobile transmission clutch plates, water pump shafts, and engine valves. Outside of the world of automobiles and tools, premium gold club heads, which take lots of abuse, are often treated with Melonite.
Melonite is one of those beautiful processes that can prolong the life of your pistol by inhibiting rust. In trials, it has shown that it is more effective than even stainless steel. Probably the closest metal treatment in its class is Glock's proprietary Tenifer process, which is legendary in the gun world. The only difference is that Tenifer is accomplished with a cyanide mixture of molten salts, but in the same process as Melonite.
In short, if you want your pistol to outlive you and still be pretty enough that your grandkids are gonna fight over who gets it, a post-2006 Springfield XD with Melonite could be just the ticket.