Outside of Haki? Yes. But a supreme grade blade reinforced with Haki (which is a swordsman bread and butter, as Ryuo allows the user to become one with his blade) would beat a great grade sword, if otherwise all parameters are the same. With beat I don't necessarily mean in terms of which blade breaks which, but in terms of attack potency and sharpness.
oda mention more than 3 times blackblades are the strongest blade in the world, also zoro said blackblades won't even bend a mile even if a dinouser stepped in it which prove non blackblades will bend
and the reason roger gets foderize by ryuma with shisui cuz rogers haki so weak compare to ryuma. man not wss not even strong enough to make a blackblade.
btw it said wb sword allow him to channel his full power in it. if zoro forge a blackblade by using full power that easily make mihawk >>> prime whitebeard / prime roger