Nonconducting samples placed in an electron microscope will build up charge on the surface, thereby diminishing image quality. One way to reduce the effects of surface charging is to coat the sample with a conductive material to give the electrons used to image the sample a path to ground. Sputter coating with Au or Au:Pd is one method to achieve this. Sputter coating uses ionized argon to vaporize gold atoms from a target and deposit them in a thin layer onto a sample.
Films: Au and Au:Pd