Should I be afraid of change in compositional variation, if the nanocomposite coating I'm concentration on with low m.p material constituents is subjected to high temperature?
Yes, nanocomposite and coating properties are dependent on processing history and therefore could change if the processing changes. For example your low MP component could surface-segragate or sublime out from the composite coating.
Any material including nanocompasosite undergoes changing under the temperature higher than its melting point. In your case as a coated material it may defuse or interacts the coated material. In all cases the nanocompasosite form will no longer remain with the the same structure form. I suggest to read the power point presentation given by M. S. Omar and available in his reseachgate
"Surface and Nanoscale materials Structure"
July 2016
DOI10.13140/RG.2.2.31947.59684
Conference: CharmoAt: University of CharmoAffiliation: University of Salahaddin