I'm currently developing a DC-DC buck converter that has a rated output of 10A/60V. When the average output current is 7.5 amps, my main inductor heats up to about 40°C (room temp's about 25°C). I made the inductor myself, with a T300 red ferrite core (OD = 7.2 cm, ID = 4.9 cm, t = 1.27 cm), and a permeability factor of 10. For the wire, I'm using a 2 mm enameled copper wire. I did around 220 turns to get 600 µH. You can see the inductor in the picture below.
My question would be, how hot can the inductor get before it causes problems in my circuit? Does operating the inductor in 40°C safe? If not, how would you recommend me lowering the wire temperature?