A thermal-gradient approach to variable-temperature measurements resolved in space
A thermal-gradient approach to variable-temperature measurements resolved in space
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DOI：
10.1107/s160057672000415x
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发表时间：
2020-06-01
影响因子：
6.1
通讯作者：
Chapman, Karena W.
中科院分区：
文献类型：
--
作者：
O'Nolan, Daniel;Huang, Guanglong;Chapman, Karena W.
温度是一个无处不在的环境变量，用于探索材料的结构、性能和反应性。本文报道了一种新的变温测量范例，该范例在样品上连续改变温度，使得温度被测量为样品位置而不是时间的函数。梯度方法提供了优于传统的变温研究，其中温度在一系列测量过程中进行扫描，因为它提高了一系列温度可以探测的效率，它允许在多个温度下平行测量样品演变，以解决动力学和热力学效应。梯度法用于在环境温度下测量之前在连续温度下处理样品，使回收系统的参数研究成为可能，消除了与温度相关的结构和化学变化，简化了数据的解释。这里提出的空间分辨可变温度测量的实现基于梯度加热器设计，该设计使用3D打印陶瓷模板来引导连续加热的绕线加热器元件中的线的可变间距。梯度加热器的配置的基础上改进的热建模。梯度加热器的应用，以量化的热膨胀行为，映射亚稳多晶型恢复到环境温度，并监测的时间和温度依赖的相演变在一个复杂的固态反应证明。
Temperature is a ubiquitous environmental variable used to explore materials structure, properties and reactivity. This article reports a new paradigm for variable-temperature measurements that varies the temperature continuously across a sample such that temperature is measured as a function of sample position and not time. The gradient approach offers advantages over conventional variable-temperature studies, in which temperature is scanned during a series measurement, in that it improves the efficiency with which a series of temperatures can be probed and it allows the sample evolution at multiple temperatures to be measured in parallel to resolve kinetic and thermodynamic effects. Applied to treat samples at a continuum of temperatures prior to measurements at ambient temperature, the gradient approach enables parametric studies of recovered systems, eliminating temperature-dependent structural and chemical variations to simplify interpretation of the data. The implementation of spatially resolved variable-temperature measurements presented here is based on a gradient-heater design that uses a 3D-printed ceramic template to guide the variable pitch of the wire in a resistively heated wire-wound heater element. The configuration of the gradient heater was refined on the basis of thermal modelling. Applications of the gradient heater to quantify thermal-expansion behaviour, to map metastable polymorphs recovered to ambient temperature, and to monitor the time- and temperature-dependent phase evolution in a complex solid-state reaction are demonstrated.