Sparks when hitting chain??! It's made of soft metal, there is no way you can get sparks by hitting chain. Pretty much the same for plates (Perhaps it's possible, but highly unlikely nonetheless. At least, I've never seen something like that.). Helmet hits - now that's possible, I've seen it myself.
It's possible to have sparks then blocked too, and it would be fun indeed. Usually it's a sign of bad blocking skill, though. Edge-to-edge parrying is bad Hollywood stereotype - well, in the hit of combat you may be forced to do that, but properly you should be meeting attacks with flat or back of the blade, or unsharpened thick portion of it (near the hilt).