I'm not 100% sure what you're asking, but ironclads evolved into more modern naval vessels: armored cruisers, dreadnoughts, etc. There's no clear point at which you can say that a naval vessel stopped being an "ironclad" but the terminology tended to be less used toward the end of the 19th century.

An old-style broadside ironclad, like a Gloire-class, was certainly obsolete a decade later with the development of casemate batteries, which were themselves supplanted by turret-based batteries, and armor was thickened and metallurgy generally improved throughout the period, but I don't think you can really say there was a well-established boundary between ironclads and their immediate successors, in anything like the sharp difference between, say, propeller-driven combat aircraft and their jet-driven successors.