Sofia,
Sugestões:
1. Flat iron
2.
Hair straightener3. Straightening iron
"A ceramic
hair straightener is any tool designed to
straighten the hair using specialized ceramic plates." (
http://www.wisegeek.com)
Da wikipedia:
A hair iron or hair tong is something people use to change the shape of the hair by heating it. There are three types of hair iron:
Straightening irons (sometimes called Hair Irons or
Hair Straighteners, or just
Straighteners), which straighten the hair
Curling tongs (sometimes called Hair Tongs or Hair Curlers or just Curlers, or less often Curling irons), which make hair curly.
Styling irons (sometimes called Hair Stylers or just Stylers), that can straighten and curl the hair.

Boa sorte!