金属氧化体积微膨胀法消除氧化镥透明陶瓷微气孔的机理研究

Lutetium oxide (Lu2O3) with high thermal conductivity is a promising host material for high-power solid-state lasers. Due to its high melting point, high optical quality large-sized transparent lutetium oxide bodies are difficult to be obtained by traditional crystal growth methods, while could be achieved by the ceramic technology involving powder densification processes at a reduced cost. However, the residual pores remained in Lu2O3 transparent ceramics decrease their laser properties, which make them inferior than that of the Lu2O3 single crystal...In order to improve the efficiency and output power of Lu2O3 laser transparent ceramics while maintaining Lu2O3’s own excellent properties, a novel method is proposed to fabricate Lu2O3 transparent ceramics by metal lutetium as a sintering aid in this project. Lutetium oxidizes during sintering and results in volume expansion, which can fill and eliminate the pores, and promote sintering. Firstly, the sintering properties of Lu2O3 transparent ceramics with SiO2 or LuF3 additive are studied, which are used for the comparison. Next, the sintering properties and mechanisms of Lu2O3 transparent ceramics with lutetium and SiO2 or LuF3 co additives are investigated. Finally, fabrication of Lu2O3 transparent ceramics with lutetium additive and its mechanism will be explored. By adjusting the lutetium additive and the sintering process, the balance between “shrinkage” and “expansion” will be achieved and the residual pores will be removed, which leads to high quality of Lu2O3 transparent ceramics...The output of this project will offer a novel fabrication method for other laser transparent ceramics with high melting points.

高热导率氧化镥是应用于高功率固体激光器的潜在优选材料。由于其熔点高，采用传统的单晶生长方法难以制备大尺寸样品；通过陶瓷制备技术则能低成本获得。然而，现阶段烧结体中的残留气孔降低了氧化镥透明陶瓷的激光性能，使之难以与其单晶相媲美。.为提高氧化镥透明陶瓷的激光输出效率和功率，同时保持其本征优异性能，本项目提出注入同质金属烧结助剂的新型透明陶瓷制备方法——利用金属镥参与氧化反应、形成体积微膨胀来填充和缩减气孔，促进烧结。分析采用SiO2或LuF3掺杂的氧化镥透明陶瓷的烧结特性，建立基础对比平台；研究和探索采用金属镥粉与SiO2或LuF3共掺杂以及纯金属镥粉掺杂的氧化镥透明陶瓷烧结规律，调控金属镥粉掺杂方式和烧结工艺，实现陶瓷制备过程中的“总体体积收缩”与“局部体积膨胀”之间的均衡、缩减微气孔，从而制备出高性能氧化镥激光透明陶瓷。.本项目的成功实施能为高熔点激光透明陶瓷提供新的制备方法。

本项目针对高功率固体激光器所需求的高热导率激光介质材料——氧化镥,采用放电等离子烧结方法，通过添加烧结助剂来制备氧化镥透明陶瓷。通过阻抗谱联合透射电镜、XPS分析了放电等离子烧结样品中颜色来源，主要来自缺氧环境的氧空位和少量碳污染，可以通过退火来消除；通过Nd掺杂离子的优化，同时探明了烧结过程中制备工艺-微观结构-透明之间的关系，制备出了激光输出的1 at% Nd3+掺杂氧化镥透明陶瓷，为该技术开发新型透明陶瓷提供了技术支撑。同时，针对该类材料作为固体电解质在燃料电池、传感器等方面应用，研究了钛酸镥、铌掺杂钛酸镥和铪掺杂钛酸镥的相演变、透过率及电导性能，逐步理解材料的高密度高纯度对其电导性能、以及实际应用中的稳定性、耐用性之间的关系，为放电等离子技术制备的透明陶瓷开拓新的应用方向。