Chahal Shweta, Prabhudessai Akila G, Shekhawat Roopali, Vinoth S, Ramesh K
Department of Physics, Indian Institute of Science, Bangalore 560012, India.
Dalton Trans. 2022 Aug 16;51(32):12100-12113. doi: 10.1039/d2dt01969h.
Thermal, optical, mechanical and structural studies were carried out on glasses in the pseudo-binary joint GeTe-AsSe prepared by a melt quenching method. (GeTe)(AsSe) glasses in the entire composition range of 0 ≤ ≤ 100 have an average coordination number () = 2.4, where the glass forming ability is found to be maximum. In general, for ≤ 2.4, the glass transition is found to be dominated by the network connectivity and the chemical composition effects are minimal. Although of GeTe (GeTe) and AsSe (AsSe) is 2.4, GeTe is a poor glass former and AsSe is an excellent glass former. The glass-forming ability is expected to increase with the addition of AsSe. Surprisingly, the glass forming ability is found to decrease with the initial addition of AsSe and then shows an increasing trend. Glass transition () shows a large variation from 175 °C for = 0 to 108 °C for = 30. Based on the variation in the properties, the tie-line can be divided into three regions: region I (0 ≤ ≤ 20) where shows a decreasing trend, region II (25 ≤ ≤ 55) where remains almost constant and region III (60 ≤ ≤ 100) where shows an increasing trend. Hardness measurement also shows a similar trend in the three regions. Thermal stability shows a continuous increase with the increase of AsSe. The fragility index varies between 15 and 30 for all these glasses except for = 0 (GeTe) indicating the strong nature of the melts containing AsSe. Raman studies indicate that the glassy network is dominated mainly by GeTe in region I and in region III the network is dominated by AsSe based structures. Glasses in region II are found to be dominated by AsTe based structures. This study brings out the dominance of chemical composition effects over the network connectivity in a critically coordinated network. These glasses are also found to transmit IR light up to 18 μm and offer a wide composition range to prepare bulk glasses to be useful for infrared applications.
采用熔体淬火法对伪二元体系GeTe-AsSe玻璃进行了热学、光学、力学和结构研究。在0≤≤100的整个成分范围内，(GeTe)(AsSe)玻璃的平均配位数() = 2.4，此时玻璃形成能力达到最大值。一般来说，当≤2.4时，玻璃转变主要受网络连通性控制，化学成分的影响最小。虽然GeTe(GeTe)和AsSe(AsSe)的为2.4，但GeTe是一种较差的玻璃形成体，而AsSe是一种优异的玻璃形成体。预计随着AsSe的加入，玻璃形成能力会增强。令人惊讶的是，发现随着AsSe的初始加入，玻璃形成能力会降低，然后呈现出上升趋势。玻璃转变()变化很大，从 = 0时的175℃到 = 30时的108℃。基于性能的变化，连接线可分为三个区域：区域I(0≤≤20)，其中呈下降趋势；区域II(25≤≤55)，其中几乎保持不变；区域III(60≤≤100)，其中呈上升趋势。硬度测量在这三个区域也呈现出类似的趋势。热稳定性随着AsSe的增加而持续提高。除了 = 0(GeTe)外，所有这些玻璃的脆性指数在15到30之间变化，这表明含AsSe熔体的性质较强。拉曼研究表明，在区域I中玻璃网络主要由GeTe主导，而在区域III中网络由基于AsSe的结构主导。发现区域II中的玻璃由基于AsTe的结构主导。这项研究揭示了在临界配位网络中化学成分效应相对于网络连通性的主导地位。还发现这些玻璃能够传输高达18μm的红外光，并提供了广泛的成分范围来制备用于红外应用的块状玻璃。
