Radiation Resistant Gear Oils

Some oils, both natural and synthetic, are more resistant to the effects of ionizing radiation than others. However, according to  Gordon and  Weir^22  resistance  to  such  action  is  increased  by  the  addition of 0.1 to 10  per cent  of  asphalteness . For best results the base oil should contain less than 0.1 per cent of asphalt. Thus, a bright  stock  containing  0.75 per cent  of  asphaltenes was  exposed to  radiation until  it  had  adsorbed  2 *10^8   rads  causing  a viscosity  increase of 31 per cent. The unmodified oil under   the same conditions increased in viscosity 48 per cent. An  oxidation  inhibitor  such  as 5  per cent  dialkyl  selenide is also  effective  in such  lubricants as  is a metal  deactivator consisting of 0.05 per cent  of  quinizarin.