Lubricating oils and greases

Lubricating oil compositions comprising:

• (A) from 0.5 to 100% by weight of a perfluoropolyether compound selected from the group consisting of:
• (1) AORY--SH (I)
• wherein
• R is a perfluoropolyether or fluoropolyether chain having a number average molecular weight comprised within the range of from 500 to 10,000;
• A is a perhaloalkyl end group, whose halogen atoms are constituted by either fluorine or fluorine and chlorine atoms;
• AOR represents:
• ##STR24## wherein A.sup.1 contains from 1 to 3 carbon atoms, and the units with formulae ##STR25## are randomly distributed along the chain;
• a, b and c are integers, wherein one from indices b and c may be 0, and the ratio of a/(b+c) is comprised within the range of from 5 to 40 ##STR26## wherein A.sup.2 contains from 1 to 3 carbon atoms and k is an integer;
• ##STR27## wherein A.sup.3 contains from 1 to 3 carbon atoms;
• the units with formulae ##STR28## are randomly distributed along the chain;
• f, g and h are integers;
• the ratio of f/(g+h) is comprised within the range of from 1 to 10, and the ratio of g/h is comprised within the range of from 1 to 10;
• ##STR29## wherein A.sup.4 contains from 1 to 3 carbon atoms;
• l is an integer and R.sup.10 and R.sup.11, which can be either the same, or different from each other, are selected from H, Cl and F;
• one fluorine atom in the --CF.sub.2 -- radicals can be replaced by H, Cl, a perfluoroalkoxy group or a perfluoroalkyl group;
• when said compound contains different ##STR30## units, these units are ramdonly distributed along the chain;
• Y is a bridging radical selected from the group consisting of ##STR31##
• (2 ) (AORY).sub.2 S (II)
• wherein AOR and Y have the same meaning as disclosed above for compounds of formula (I)
• (3) (AORY).sub.2 S.sub.2 (III)
• wherein AOR and Y have the same meaning as disclosed for compounds of formula (I)
• (4) (AORYZ).sub.3 P.dbd.Z (IV)
• wherein Z is either O or S and AOR and Y have the same meaning as disclosed for compounds of formula (I) ##STR32## in which Z is either O or S and AOR and Y have the same meaning as disclosed for compounds of formula (I);
• R' is a perfluoropolyether chain having a number average molecular weight comprised within the range of from 500 to 10,000, selected from the group consisting of:
• (a') (C.sub.2 F.sub.4 O).sub.d (CF.sub.2 O).sub.e
• wherein the units with formulae C.sub.2 F.sub.4 O and CF.sub.2 O are randomly distributed along the chain, and d and e are integers, whose ratio, d/e, is comprised within the range of from 0.3 to 5 ##STR33## as described under above (c) point ##STR34## as described under above (d) point, (B) from 99.5% to 0% by weight of one or more perfluoropolyethers with perfluoroalkyl end groups.