Phase Equilibria in Thallium Based Superconducting Films

铊超导系统的相平衡将 被衡量。 我们的目标是了解复杂的固体-液体- 控制铊基晶体生长的蒸汽平衡 超导体家族 本研究将涉及暴露于 薄膜和已知成分的粉末混合物， 氧化亚铊和氧蒸气在高温下的超压 温度（600 - 950 ℃），然后淬火。 所述组合物 淬火试样的显微组织将被检查， 确定平衡高温相。 以这种方式 液相线和固相线温度，平衡超压， 在这些区域中将确定稳定相， 这对薄膜和晶体生长很重要。 关于相变的更多信息将通过以下方式获得： 差热分析（DTA）使用密封的金安瓿， 控制铊挥发性。

Phase equilibria in the thallium superconducting system will be measured. The goal is to understand the complex solid-liquid- vapor equilibria that govern crystal growth of the thallium based family of superconductors. This study will involve exposure of films and powder mixtures of known composition to controlled overpressures of thallous oxide and oxygen vapor at high temperature (600 - 950 C) followed by quenching. The composition and microstructure of quenched samples will be examined to identify the equilibrium high temperature phases. In this manner the liquidus and solidus temperatures, equilibrium overpressures, and stable phases will be determined in those regions of composition that are important for thin film and crystal growth. Additional information on phase changes will be gained by differential thermal analysis (DTA) using sealed gold ampoules to control thallium volatility.