I like that this is actual "science", as opposed to plasma or aether or some such thing, and this will work fine on low-grade civilian stuff, but... well, it'll do absolutely nothing against anything above steel or titanium armor. An armor-piercing tank round is only rated at DR 3, and while Potassium and Sodium are certainly nasty things, they're not DR 6 nasty, which would put its destructive power above that of a tactical nuclear weapon or a mid-grade railgun. I'd suggest a DR of 3, honestly.