模拟高放废液硼硅酸盐玻璃固化体钼分相与化学稳定性的结构基因模拟

碱金属钼酸盐黄相在高放废液玻璃固化过程中难以处理,严重影响玻璃的化学稳定性。为了对高钼废液固化玻璃的化学稳定性进行较为准确的预判,从而加速配方研发进程,利用玻璃结构基因模拟法(GSg M)研究了高Mo (2.6%~3.3%,质量分数)模拟高放废液硼硅酸盐玻璃的化稳性和钼分相累积情况,建立了B、Li、Na、Mo浸出率、玻璃转变温度和钼分相累积程度的结构预测模型,并进行了模型验证。研究显示,在本工作的成分研究范围内,钼分相成分主要为CsLiMoO_(4)(水溶性黄相)及CaMoO_(4)(耐水性晶相)。成分–结构–性质关系表明,提高Li_(2)O和CaO会显著促进钼分相的形成。518~528 cm^(-1)Si—O—Si振动增强,则钼分相加剧,但[BO_(3)]基团中B—O—B振动增强,可有效减少钼分相的析出。模型验证结果表明,各性质的结构预测模型可对设计玻璃的化稳性及钼分相累积程度进行快速预测,以筛选设计玻璃配方是否有进一步研究的必要。

Comparative Investigation of Mo（CO）6 Adsorption on Clean and OxidiZed Si（111） Surfaces

Mo（CO）6 adsorption on the clean, oxygen-precovered and deeply oxidized Si（lll） surfaces was comparatively investigated by high-resolution electron energy loss spectroscopy. The downward vibrational frequency shift of the C-O stretching mode in adsorbed Mo（CO）6 illustrates that different interactions of adsorbed Mo（CO）6 occur on clean Si（111） and SiO2/Si（111） surfaces, weak on the former and strong on the latter. The strong interaction on SiO2/Si（111） might lead to the partial dissociation of Mo（CO）6, consequently the formation of molybdenum subcarbonyls. Therefore, employing Mo（CO）6 as the precursor, metallic molybdenum could be successfully deposited on the SiO2/Si（111） surface but not on the clean Si（111） surface. A portion of the deposited metallic molybdenum is transformed into the MoOa on the SiO2/Si（111） surface upon heating, and the evolved MoO3 finally desorbs from the substrate upon annealing at elevated temperatures.