[summerfish]

I have a DSC curve for sapphire (ramp 20*C/min from 40*C to 200*C).

I'm having trouble understanding why the heat flow increases linearly as the temperature increases before it has even reached its melting point... I would have expected the heat flow to remain constant until reaching its melting point, at which time the curve would peak endothermically.

Any insights are much appreciated.

Thanks!

[Borek]

I would have expected the heat flow to remain constant until reaching its melting point

Just a guess: that happens when heat capacity is temperature indepenedent.