An engineer must select a solid material for a heat-dissipation plate in high-temperature electronics that will operate continuously at 2500 K. Four candidate materials are under consideration:
• Diamond (a three-dimensional covalent network of carbon)
• Graphene sheet (a single two-dimensional layer of sp²-hybridized carbon atoms)
• A tungsten-based alloy (metallic solid)
• KBr (ionic solid)
In addition to withstanding the operating temperature without melting, the plate must conduct heat efficiently and possess moderate electrical conductivity.
(a) Rank the four candidate materials from lowest to highest melting point.
(b) For each material, evaluate whether it meets the minimum requirement of remaining solid at 2500 K. Support your answer with quantitative or qualitative data as appropriate.
(c) Discuss the relative thermal and electrical conductivities of the four materials, citing structural features that account for the observed properties.
(d) Based on all of the above considerations, identify the single best material for the engineer’s application and provide a comprehensive justification for your choice.