We demonstrated Arrhenius-like rate behavior for sublimation of an Hf NP, with evidence of the effects of a solid-solid phase transition in the temperature range in which bulk Hf is known to undergo a bcc-to-hcp transition, and showed how it is possible obtain information regarding fragmentation processes of individual highly charged NPs at high reaction rates. Additional multi-ramp sublimation experiments will be needed to follow the changes in sublimation rates as the NP surface evolves under sublimation conditions.