微波法制备YAG粉体微观结构的调控及其烧结性的研究

发布时间：2018-05-19 06:09

本文选题：YAG + 微波辅助均相沉淀法　；参考：《山东大学》2011年博士论文

【摘要】：YAG透明陶瓷因其具有热导率高、热膨胀系数小、硬度大、光学特性优异等众多特点,而成为开发光学器件首选的基质材料。本文以廉价的无机盐为原料,分别采用碳酸氢铵共沉淀法和微波辅助均相沉淀法制备YAG纳米粉体,通过真空烧结,成功地制备了YAG透明陶瓷。首次利用微波辅助均相沉淀法制备的Nd:YAG透明陶瓷实现了激光输出,证明此方法在制备Nd:YAG透明陶瓷方面有一定的潜力。论文首次重点研究了在微波辅助均相沉淀法制备Nd:YAG纳米粉体过程中陈化作用(陈化过程中状态、时间、温度和湿度)对Nd:YAG纳米粉体的影响,进而找出了制备分散性均良好和可烧结性优良的Nd:YAG纳米粉体的最佳工艺,并对真空烧结YAG陶瓷透明机理进行了初步地探讨。论文主要研究内容及结论包括： 1)在碳酸氢铵沉淀法制备YAG纳米粉体过程中重点研究了母盐溶液的浓度、母盐溶液的滴加速度及有机溶剂对制备YAG纳米粉体的影响： (1)母盐溶液的浓度对生成YAG前驱体及煅烧粉体的形貌产生了显著的影响。只有低浓度的母盐溶液([Y3+]=0.08M,[Al3+]=0.13M)生成的前驱体具有较好的分散性,更有利于获得颗粒分散均匀,形状近似球形的YAG纳米粉体。母盐溶液的浓度对合成的YAG纳米粉体的物相的影响并不是太明显,但相对来讲低溶度的母盐溶液能够获得具有更好的YAG物相的纳米粉体； (2)母盐溶液的滴加速度的影响比较显著。当母盐溶液和NH4HC03沉淀剂溶液混合速度比较快时更容易获得具有较好的YAG物相的纳米粉体,且低浓度的母盐溶液和NH4HC03溶液混合速度比较快时,更容易获得具有较好物相的YAG纳米粉体,同时生成YAG纳米粉体具有良好的烧结性； (3)少量有机溶剂(有机溶剂与母盐溶液体积比为1：5)对YAG纳米粉体的物相和形貌有一定影响。加入少量乙醇作为溶剂对获得纯相YAG纳米粉体具有较好效果,低浓度母盐溶液中加入少量乙醇和NH4HC03沉淀剂溶液快速混合可以获得纯物相和颗粒形貌很好的YAG纳米粉体,因此母盐溶液中加入少量的乙醇对制备性能稳定的YAG纳米粉体有一定作用。实验中所制备的YAG粉体能够烧结出透明陶瓷,证明通过系统地控制上述三个因素可以得到具有良好烧结性的YAG纳米粉体。 2)在微波辅助均相沉淀法制备Nd:YAG纳米粉体过程中研究了母盐溶液的浓度、尿素用量、分散剂(NH4)2S04的用量和陈化作用对制备Nd:YAG纳米粉体的影响： (1)反应物母盐溶液的浓度、尿素用量和分散剂(NH4)2S04的用量对制备Nd:YAG纳米粉体性质的影响是基本应该考虑的,在本实验中反应母盐溶液的浓度为[Nd3++Y3+]=0.06M,[A13+]=0.1M,尿素与金属离子的物质的量比25：1,分散剂(NH4)2S04的用量为母盐溶液中所有硝酸盐质量的8%,这些值为制备Nd:YAG纳米粉体最佳值； (2)陈化状态和陈化时间对Nd:YAG纳米粉体的物相和形貌的影响很明显。Nd:YAG前驱体在反应釜中陈化的效果比在空气中的陈化效果更好,更有利于获得颗粒尺寸均匀,形状近似椭圆的Nd:YAG纳米粉体,但陈化过程中仍旧需要一定的物质交换,表现出陈化作用对外界环境的敏感性。Nd:YAG前驱体在反应釜中随着陈化时间的变化,获得的Nd:YAG纳米粉体的颗粒尺寸先减小后增大,在本实验中是在反应釜中陈化6天后得到的Nd:YAG纳米粉体的粒径最小； (3)陈化环境的湿度和温度对Nd:YAG纳米粉体物相和形貌的影响比较明显。湿度和温度对Nd:YAG纳米粉体的影响有一定的依存关系,因此在制备Nd:YAG纳米粉体过程中必须控制陈化环境合适的湿度和温度,目前本实验的湿度控制在30%-50%,温度在25℃,能够得到的性质较好的Nd:YAG纳米粉体。 3)为了成功地制备Nd:YAG透明激光陶瓷,Nd:YAG纳米粉体必须要具有的性质： (1)为了获得Nd:YAG透明陶瓷,必须首先制备出具有纯YAG相的Nd:YAG纳米粉体； (2)为了获得高质量的Nd:YAG纳米粉体,必须严格控制影响Nd:YAG纳米粉体性质的各种因素。所制备的Nd:YAG纳米粉体必须在物理和化学性质上具有相对稳定性,同时也应该具有一定的烧结活性来保证Nd:YAG透明陶瓷的成功烧结,因此制备的Nd:YAG纳米粉体要具有较小尺寸的颗粒、较窄的颗粒尺寸分布和较低的缺陷密度,这样的Nd:YAG纳米粉体将有助于获得具有良好性能的Nd:YAG透明陶瓷； (3)最终所制备的Nd:YAG纳米粉体除了具有纯YAG相,较小尺寸的颗粒、较窄的颗粒尺寸分布和较低的缺陷密度外,还应具有均匀的微观组分和适当的化学计量比的偏移程度,这些性质最终保证能够获得具有良好性能的Nd:YAG透明陶瓷； (4)在温度在25℃,湿度在30-50%之间,反应釜中陈化6天的Nd:YAG纳米粉体真空1730℃烧结10h获得的经过精抛的Nd:YAG透明陶瓷片激光的激光输出能量可达305 mW,斜率为5.1%。
[Abstract]:YAG transparent ceramics have many characteristics, such as high thermal conductivity, small thermal expansion coefficient, large hardness and excellent optical properties, and become the first choice material for developing optical devices.
In this paper, YAG nano powders were prepared by the method of ammonium bicarbonate co precipitation and microwave assisted homogeneous precipitation, and the transparent YAG ceramics were prepared by vacuum sintering, and the Nd:YAG transparent ceramics prepared by microwave assisted homogeneous precipitation method were realized for the first time. It was proved that this method was used in the preparation of Nd:YAG penetration. The bright pottery has a certain potential.
In this paper, the effect of aging (state, time, temperature and humidity) on the Nd:YAG nano powders during the preparation of Nd:YAG nano powder by microwave assisted homogeneous precipitation method was emphatically studied. The best process of preparing Nd: YAG nano powder with good dispersibility and good sintering ability was found, and the vacuum sintering YAG was also studied. The mechanism of ceramic transparency was preliminarily discussed.
1) in the process of preparing YAG nano powder by ammonium bicarbonate precipitation method, the concentration of the mother salt solution, the drop acceleration of the mother salt solution and the effect of organic solvent on the preparation of YAG nano powder were studied.
(1) the concentration of the mother salt solution has a significant influence on the morphology of the YAG precursor and the calcined powder. Only the precursors generated by the low concentration of the mother salt solution ([Y3+]=0.08M, [Al3+]=0.13M) have good dispersion, and are more favorable for obtaining the homogeneous and nearly spherical YAG nanoparticles. The influence of the phase of YAG nanopowders is not too obvious, but relatively low solubility of the parent salt solution can obtain nano powders with better YAG phase.
(2) the drop acceleration of the mother salt solution is more significant. When the mixture rate of the mother salt solution and the NH4HC03 precipitant solution is faster, the nano powders with better YAG phase are easier to be obtained. And the low concentration of the mother salt solution and the NH4HC03 solution will be easier to obtain the YAG nano powder with better phase. The YAG nanoscale powders have good sintering properties.
(3) a small amount of organic solvent (the volume ratio of organic solvent and mother salt solution is 1:5) has a certain effect on the phase and morphology of YAG nano powders. Adding a small amount of ethanol as a solvent has a good effect on obtaining pure phase YAG nano powder. A small amount of ethanol and a fast mixture of NH4HC03 precipitant solution in the low concentration mother salt solution can obtain the pure phase. YAG nano powder with good particle morphology, so the addition of a small amount of ethanol in the mother salt solution has a certain effect on the preparation of stable YAG nano powders. The YAG powders prepared in the experiment can be sintered transparent ceramics. It is proved that the fine sintered YAG nano powders can be obtained by controlling the above three factors systematically.
2) in the preparation of Nd:YAG nano powders by microwave assisted homogeneous precipitation, the influence of the concentration of the mother salt solution, the amount of urea, the dosage of NH4 2S04 and the aging effect on the preparation of Nd:YAG nano powders were studied.
(1) the influence of the concentration of the reactant mother salt solution, the amount of urea and the dosage of the dispersant (NH4) 2S04 on the properties of the Nd:YAG nano powder should be considered basically. In this experiment, the concentration of the mother salt solution is [Nd3++Y3+]=0.06M, [A13+]=0.1M, the quantity of the substance of the urea and the metal ions is 25:1, the dosage of the dispersant (NH4) 2S04 is the mother salt. 8% of the total nitrate content in the solution is the best value for preparing Nd:YAG nanopowders.
(2) the effect of aging state and aging time on the phase and morphology of Nd:YAG nano powders shows that the aging effect of.Nd:YAG precursor in the reaction kettle is better than that in the air, and it is more beneficial to obtain Nd:YAG nanoparticles with uniform particle size and ellipse shape, but it still needs a certain material exchange during the aging process. The susceptibility of.Nd:YAG precursors to the external environment is shown to be reduced and then increased with the aging time of the precursor in the reaction kettle. In this experiment, the particle size of the Nd:YAG nano powders obtained after the reaction of the reaction of Fu Zhongchen 6 days is the smallest.
(3) the influence of humidity and temperature on the phase and morphology of Nd:YAG nano powder is obvious. Humidity and temperature have a certain dependence on the effect of Nd:YAG nano powder, so the appropriate humidity and temperature must be controlled in the process of preparing Nd:YAG nano powder. The humidity of this experiment is at 30%-50% and temperature at present. Nd:YAG nanoparticles with better properties can be obtained at 25 degrees centigrade.
3) in order to prepare Nd:YAG transparent laser ceramics successfully, the Nd:YAG nanopowders must possess the following properties:
(1) in order to obtain Nd:YAG transparent ceramics, Nd:YAG nanopowders with pure YAG phase must first be prepared.
(2) in order to obtain high quality Nd:YAG nano powders, various factors affecting the properties of Nd:YAG nano powders must be strictly controlled. The prepared Nd:YAG nano powders must have relative stability in physical and chemical properties, and also have certain sintering activity to ensure the successful sintering of Nd:YAG transparent ceramics, so the prepared Nd:Y AG nano powders have smaller size particles, narrower particle size distribution and lower defect density. Such Nd:YAG nano powders will help to obtain good properties of Nd:YAG transparent ceramics.
(3) in addition to the pure YAG phase, the smaller size particles, the narrow particle size distribution and the lower defect density, the Nd:YAG nano powders should also have the uniform microscopic composition and the appropriate offset degree of the stoichiometry. These properties ultimately guarantee the good performance of the Nd:YAG transparent ceramics.
(4) when the temperature is at 25, the humidity is between 30-50%, and the Nd:YAG nanometer powder of 6 days in the reaction kettle is sintered at 1730 C for 6 days. The laser output energy of the fine cast Nd:YAG transparent ceramic sheet is 305 mW and the slope is 5.1%..
【学位授予单位】：山东大学
【学位级别】：博士
【学位授予年份】：2011
【分类号】：TB383.1

【引证文献】