Curable fluoroelastomer composition

Compositions comprising fluoroelastomers having copolymerized units of a cyano-containing cure site monomer are cured (i.e. crosslinked) with a fluoropolymer having pendant sulfonyl azide groups. The latter fluoropolymer comprises copolymerized units of a fluoroalkanesulfonyl azide of formula CF 2 ═CF—(O) p —R f —(CH 2 ) n —SO 2 N 3 , wherein p=0 or 1; n=0-4; and R f is a C 1 -C 16 perfluoroalkyl or perfluoroalkoxy group. The crosslinks are tetrazole rings formed by the reaction of the pendant sulfonyl azide groups on the fluoropolymer with pendant cyano groups on the fluoroelastomer.