X-ray diffraction on – and – composites

We have identified the crystallographic phases of the melt-quenched superionic composites – and – by X-ray diffraction. Measurements were made in a temperature range from 300 to 630 K. The materials have a glass phase and one or more crystalline phases. At 300 K and at 350 K, the crystalline phase contains a 30:70 mixture of AgI and AgI. Above 350 K, the fraction of AgI increases and at 403 K it is the dominant phase with a – ratio of about 70:30 (slightly less in – ). At 453, 523 and 623 K the crystalline material is mainly AgI. Crystalline 16-silver dodecaiodide diphosphate () is also present between 373 and 523 K at a 5–10% level. It disappears at 623 K because the crystal melts.