Phase diagrams and X-ray powder diffraction patterns provide critical information for thermoelectric research. We have conducted a survey of phase diagrams and powder diffraction patterns of thermoelectric systems in the ASM Metal/Alloy database and ICDD Powder Diffraction File (PDF), respectively, for their availability and crystal systems. In this report, we focus on thermoelectric materials that have the half-Heusler XYZ structure, and related compounds, based on a set of materials selection rules. We found that among 306 potential XYZ compounds that we have surveyed, 234 have powder diffraction patterns in the PDF, but only 28 have phase diagram information. Among the 234 phases with powder patterns, 84 were reported to have Cubic F-43m half-Heusler type structure, the remainder have hexagonal, orthorhombic or other structure types. Some XYZ compounds have both cubic and hexagonal phases. This information will provide the basis for future activities for improvement of the databases. These activities include filling the missing gaps in both phase equilibria database and the PDF, as well as adding thermoelectric and pertinent physical properties to the PDF.
Thermoelectric half-Heusler compounds, ASM Phase Diagram Database, ICDD PDF, survey