This also depends where they're fighting at, if black panther is in wakanda he can easily beat him. Also another thing black panther is a far superior fighter, iron relies to much on his suit which BP can take advantage of. Also, T'Challa's Vibranium-weave uniform absorbs the kinetic force of impacts, rendering him bulletproof. His costume's gloves can generate energy daggers and house anti-metal claws that dissolve other metals on contact. His Kimoyo Card enables global communication, picks up satellite signals, and can block most radio transmissions. In other words I don't think particle beams might hurt him.