Source : Webster's Revised Unabridged Dictionary (1913)

Decrepitation \De*crep`i*ta"tion\, n. [Cf. F.
   d['e]cr['e]pitation.]
   The act of decrepitating; a crackling noise, such as salt
   makes when roasting.

Source : WordNet®

decrepitation
     n : the crackling or breaking up of certain crystals when they
         are heated