Fusibility

Fusibility is the ease with which a material will melt. Materials such as solder require a low melting point so that when heat is applied to a joint, the solder will melt before the materials being soldered melt, i.e. high fusibility. On the other hand, firebricks used for furnace linings only melt at very high temperatures and so have low fusibility. Materials that only melt at very high temperatures are called refractory materials.