Study on thermophysical properties and phase evolution in Nd doped Li2O-Al2O3-SiO2 glass nucleated by multiple nucleating agents
Study on thermophysical properties and phase evolution in Nd doped Li2O-Al2O3-SiO2 glass nucleated by multiple nucleating agents
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DOI：
10.1016/j.jnoncrysol.2016.05.035
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发表时间：
2016-09
影响因子：
3.5
通讯作者：
Richa Mishra;M. Goswami;A. Dixit;M. Krishnan
中科院分区：
文献类型：
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作者：
Richa Mishra;M. Goswami;A. Dixit;M. Krishnan
采用熔融淬火法制备了(1)LASa: 59sio2 - 19al2o3 -3.5 li2o - 5b2o3 -1.5 zno - 1mgo - 2tio2 - 2zro2 - 7p2o5和(2)LASb: 58sio2 - 19al2o3 -3.5 li2o - 5b2o3 -1.5 zno - 1mgo - 2tio2 - 2zro2 - 7p2o5 - 1nd2o3玻璃，并将其转化为微晶玻璃。在玻璃样品中，nd2o3的加入提高了玻璃化转变温度（Tg）和结晶温度。热力学分析（TMA）表明，结晶样品具有非常低的热膨胀系数（α），约为2.5 × 10−6/°C（30-300）。晶化样品的显微硬度和密度值均高于基体玻璃。采用x射线衍射（XRD）和扫描电镜（SEM）分析了玻璃/玻璃陶瓷样品中相的性质及其微观结构。850℃热处理后的XRD结果表明，β-锂辉石（LiAlSi2O6）为主要晶相，而Berlinite （AlPO4）和Srilankite （TiZrO4）为次要晶相。675℃热处理后的LASa和LASb样品的显微结构显示，在玻璃基体内形成了TiZrO4纳米晶（尺寸< 50 nm）。而在最高850℃下热处理的样品显示出壳型/球形颗粒结构的形成，支持这些样品的三维或块状结晶。在675℃热处理后，用微激光拉曼光谱证实了tizro4相的存在。通过记录不同扫描速率下的DTA痕迹，进行了结晶动力学研究。采用Kissinger和Marotta方法及Augis-Bennett方程计算活化能E和Avrami参数n。LASa和LASb玻璃的结晶活化能分别为263 kJ/mol和270 kJ/mol，而LASa和LASb玻璃的Avrami参数(n)分别大于2和4。Avrami参数大于2表明锂辉石相接近三维生长，显微结构分析也证实了这一点，参数大于4表明界面控制生长。
Lithium aluminium silicate (LAS) glasses of compositions (wt%) (1) LASa: 59SiO2-19Al2O3-3.5Li2O-5B2O3-1.5ZnO-1MgO-2TiO2-2ZrO2-7P2O5and (2) LASb: 58SiO2-19Al2O3-3.5Li2O-5B2O3-1.5ZnO-1MgO-2TiO2-2ZrO2-7P2O5-1Nd2O3were prepared by melt-quench technique and converted to glass-ceramics. In glass samples, addition of Nd2O3showed an increase in the glass transition temperature (Tg) and crystallization temperature. Thermo-mechanical analysis (TMA) showed that crystallized samples have very low thermal expansion coefficient (α) of value around 2.5 × 10− 6/°C (30–300). The microhardness and density values of crystallized samples were found to be higher than the base glasses. XRD and SEM techniques were employed to see nature of phases and their microstructures in glass/glass ceramic samples. From XRD formation ofβ-spodumene (LiAlSi2O6) as major crystalline phase while Berlinite (AlPO4)and Srilankite (TiZrO4) were identified as minor crystalline phases after heat treatment at 850 °C.·The microstructure of LASa and LASb samples heat treated at 675 °C showed formation of nanocrystals (size < 50 nm) of TiZrO4within the glass matrix, whereas samples heat treated at maximum 850 °C showed formation of shell type/spherical particles structure which support the three dimensional or bulk crystallization in these samples. Micro-laser Raman spectroscopy was carried out to confirm presence of TiZrO4phase after heat treatment at 675 °C. Crystallization kinetics study was carried out by recording DTA traces at different scanning rate. Activation energy (E) and Avrami parameter (n) were calculated by using Kissinger and Marotta methods and Augis-Bennett equation. Activation energy of crystallization for LASa and LASb were found to be 263 kJ/mol and 270 kJ/mol, respectively whereas the Avrami parameter (n) for LASa and LASb glass was found to be greater than 2 and greater than 4, respectively. Avrami parameter greater than 2 indicates near three dimensional growth of spodumene phase, which is also confirmed by microstructural analysis and parameter greater than 4 indicated interfacial controlled growth.