Blade coatings

So I’ve come to this forum looking for info on blade coatings. I am asking about bugouts through the custom shop. I see this forum is about griptilian, but I assume the name is just out of date as the custom shop has expanded its line.

So what I want to know is if I pick the black blade option what am I getting?

Does it vary steel to steel? I know M4 is ceracote, makes sense for corrosion resistance on that steel. But on something like 20CV it doesn’t make sense, I’d hope for a more scratch resistant coating like DLC.

now to not clutter this forum with a bunch of topics I want to ask a second related question, what is the ‘default’ black coating when it’s not noted? How about other coating not given descriptions? In this I ask about not just in the custom shop but all knives. For instance I know the 535gry-1 has a chromium nitride coating. That was not originally listed by benchmade. BladeHQ does list that.

Ultimately I’m looking for dlc coated S90V and 20cv for builds. The only blades I can find as dlc are s30v on the bladehq site.

Thank you!