PREPARATION OF COPPER-RUBY GLASSES BY SPUTTERING - THE EFFECT OF ATMOSPHERE ON THE GROWTH OF COPPER PARTICLES

Copper-ruby glasses were prepared by the sputtering method and the eff ect of reducing treatment was examined, The reducing was carried out e ither during sputtering or heat treatment. Optical absorption was rela ted to the growth of copper particles. The results are summarized as f ollows: (i) the volume fraction of copper particles in the glasses whi ch are heat-treated in air increases with the addition of hydrogen in the sputtering gas, (ii) The copper particles do not grow larger than 8 nm by heat treatment in reducing atmosphere, whereas they grow as la rge as 12 nm in air, (iii) Reducing during heat treatment gives a pron ounced effect only when sputtering was not carried out under reducing conditions, The origin of these phenomena was also discussed, consider ing the mechanism of nucleation and growth of copper particles.