Are Apiezon greases resistant to radiation?
Apiezon L and M greases show a degree of radiation resistance with only a comparatively small increase in stiffness after irradiation with 4 MeV electrons to a level of about 100 Mrads. After this exposure the lubrication properties of the grease are still satisfactory and this is true at even higher levels of irradiation, although the stiffness increases more rapidly. At high levels of irradiation small quantities of gases, (mainly methane and ethylene) are evolved so that the grease loses its very low vapour pressure characteristics. Nevertheless Apiezon greases L and M are markedly better lubricants at high irradiation levels than other high vacuum lubricants such as silicones, esters and halogenated products.
