108mAg tracer diffusion in HgI2–Ag2S–As2S3 glass system

Mercury iodide additions to the Ag2S–As2S3 glass system increase the electrical conductivity even though the silver content decreases, in particular, for the (HgI2)x(Ag2S)50 − x/2(As2S3)50 − x/2 series. 108mAg tracer diffusion and Wagner dc polarization measurements confirm that the conductivity is ionic thus excluding a possible change from ionic to electronic conductivity with increasing x. Conductivity simulations have been carried out to verify whether an exchange reaction between silver sulfide and mercury iodide could explain the ion transport evolution. The results are only partly consistent with the experiment and suggest the appearance of extrinsic conduction pathways which need to be verified unambiguously.