van Ogtrop Ilse, Navarathna Amy, Schreuders Herman, Dam Bernard, Bannenberg Lars J
Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft, The Netherlands.
ACS Appl Mater Interfaces. 2025 Jul 30;17(30):43122-43134. doi: 10.1021/acsami.5c09600. Epub 2025 Jul 18.
Thin film metal hydride optical sensors, especially those made from tantalum, offer a large, hysteresis-free hydrogen sensing range, fast response times and great stability. However, due to the shift in tantalum's hydrogen sensing ranges with rising temperatures, tantalum becomes inadequate for the detection of low hydrogen concentrations (<10 ppm) above 200 °C, making it unsuitable for high-temperature applications. We show that the properties of tantalum can be tailored by alloying tantalum with hafnium. Optical transmission measurements, ex situ and in situ X-ray diffraction and X-ray and neutron reflectometry are used to show that the introduction of Hf in Ta results in a solid solution with a stable structure with up to 21% Hf. Alloying Ta with Hf expands the unit cell, which alters the enthalpy of hydrogenation and shifts the sensing range to lower concentrations. Moreover, alloying Ta with Hf improves the sensitivity at low hydrogen concentrations (<10 ppm) and for temperatures exceeding 200 °C by about two times compared to pure Ta while preserving its large, hysteresis-free sensing range and excellent stability.
薄膜金属氢化物光学传感器，尤其是由钽制成的传感器，具有较大的、无滞后的氢传感范围、快速响应时间和高稳定性。然而，由于钽的氢传感范围随温度升高而发生变化，钽在200°C以上检测低氢浓度（<10 ppm）时变得不适用，使其不适用于高温应用。我们表明，通过将钽与铪合金化可以调整钽的性能。利用光学透射测量、非原位和原位X射线衍射以及X射线和中子反射测量表明，在钽中引入铪会形成一种结构稳定的固溶体，铪含量高达21%。钽与铪合金化会扩大晶胞，这会改变氢化焓并将传感范围转移到更低浓度。此外，钽与铪合金化提高了在低氢浓度（<10 ppm）以及温度超过200°C时的灵敏度，与纯钽相比提高了约两倍，同时保留了其较大的、无滞后的传感范围和出色的稳定性。
