高性能Nd：YAG激光透明陶瓷的制备及激光实验

发布时间：2018-03-29 07:56

本文选题：Nd:YAG　切入点：热处理　出处：《西安电子科技大学》2015年硕士论文

【摘要】：掺钕钇铝石榴石(Nd:YAG)多晶陶瓷可避其单晶和玻璃之劣势而集两者之优势于一身,具有良好的光学性能和机械强度以及稳定的物理化学性质,被广泛应用于激光增益介质及透明窗口材料。本论文选用高纯商业氧化钇、氧化铝、氧化钕为原料,以正硅酸乙酯和氧化镁为烧结助剂,采用固相反应法,利用真空烧结技术,在高温下制备1at%Nd:YAG激光透明陶瓷。实验中,我们深入研究和讨论了原料Y_2O_3不同温度热处理对样品透过率的影响及其机理;运用高能球磨机制备了粒度较小、尺寸均一的Y_2O_3粉体,并使用其制备了实验样品且展开了相关分析;运用冷等静压技术制备样品素坯,并与传统手动压片对比中体现其优势;将真空烧结过程的升温阶段和保温阶段分而研究,在详细对比分析其现象和探讨机理中,确定最佳升温速率和保温时间;探究了退火处理影响样品透过率的内因;最终进一步改进实验方案,制得高质量实验样品,并搭建出光系统,对样品进行出光试验。最终我们得到如下结论:1)基于电镜扫描图(SEM)的观察,氧化钇原料颗粒为有断层的块状结构,且有大量空隙存在于断层之中,这些空隙在一定程度上会形成样品内部影响透过率的气孔。对氧化钇进行热处理,能有效消除这些空隙,进而减少样品内气孔的形成而提高样品透明度。2)通过高能球磨机球磨处理,可得到粒度较小、尺寸均一的Y_2O_3原料粉体,理论上讲,粒度减小则比表面积增大,活性增强,可促进烧结过程的进行并提高其致密化程度。3)运用冷等静压机压片,可使得样品素坯具有良好的致密性和均匀性,一方面可在烧结前最大程度减少样品内部的气孔,另一方面良好的均匀性有利于样品在烧结过程中形成尺寸均匀的晶粒,而减少光在样品内部的损耗,从而提高样品透过率。4)烧结过程升温速率为1℃/1.5min,既可为样品内气孔排出提供足够时间,又不至于晶粒生长过大晶界数量减少而减少气孔排出通道,此升温速率下制备的样品透过率高。5)烧结过程中保温时间的延长,有利于气孔的最大化排出和增加样品的致密性,进而提高样品透过率。在实验对比中发现,保温时间超过30h后,样品透过率增加极其微小,综合考虑实验成本和要求,将30h确定为实验的最佳保温时间。6)退火处理可有效消除样品内的氧空位和应力,提高样品在可见光范围内的透过率。7)最后的出光实验不理想,分析其原因一方面可能是陶瓷样品阈值问题,微小气孔和杂质构成的第二相形成光的散射和吸收中心,降低样品对808nm波长入射光的吸收利用;另一方面可能是样品的实际厚度较薄,小于波长为808nm光进入样品体内强度将为原强度1/e时的吸收长度,以致不能产生足够能量来稳定发射波长为1064nm激光。
[Abstract]:Neodymium doped yttrium aluminum garnet (Nd:YAG) polycrystalline ceramics can avoid the disadvantages of the single crystal and glass and set their advantages in one, with physical and chemical properties, optical properties and good mechanical strength and stability, is widely used in laser gain medium and a transparent window material. The use of high pure commercial yttrium oxide, aluminum oxide, neodymium oxide as raw materials, using TEOS and Magnesium Oxide as sintering additive by solid phase reaction method by vacuum sintering technology, the preparation of 1at%Nd:YAG transparent laser ceramic at high temperature. In the experiment, we studied and discussed the raw materials of Y_2O_3 with different heat treatment temperature on the sample transmittance of the effect and mechanism of small size; by using high energy ball mill, Y_2O_3 powder with uniform size, and using the same experimental samples were prepared and analyzed; samples blank by cold isostatic pressing technology, and with the traditional manual The advantages of tablet contrast; temperature stage vacuum sintering process and heat preservation and research, in the detailed comparative analysis of the phenomenon and to explore the mechanism, determine the optimal heating rate and holding time; to explore the effect of annealing the sample through the rate of internal cause; finally further improve the experiment, make high quality experiment the sample, and build a system of light, light of test samples. Finally we get the following conclusions: 1) scanning electron microscope (SEM) based on the observation of yttrium oxide particles as raw materials, fault block structure, and there is a large gap exists in the fault, the gap formed inside the sample through the effect rate porosity to some extent. Heat treatment of yttrium oxide, can effectively eliminate these gaps and reduce the formation of pores in the samples and improve the sample.2) by high energy ball milling transparency, particle can be obtained Small, Y_2O_3 powder with uniform size, in theory, particle size reduces the surface area increase, enhanced activity, can promote the sintering process and improve the densification of.3) by cold isostatic press press, can make the sample blank with good compactness and uniformity, on the one hand before sintering to minimize pores inside the sample, even on the other hand is beneficial to the formation of uniform grain size of samples during sintering process, and reduce the loss of light inside the sample, thereby improving the sample transmittance.4) sintering process heating rate is 1 DEG /1.5min, can provide enough time for the sample air discharge, without excessive grain growth and reduce the grain boundary to reduce the number of air outlet channel, the heating rate of the sample prepared by high rate.5) prolongation of the sintering process, the maximum benefit of stomata Discharge and increase the density of the sample, and then improve the sample transmittance. Found in the experiment, the holding time is over 30h, the sample transmittance increase is extremely small, considering the experimental cost and requirements, identify 30h as the best heat preservation time.6 experiment) annealing treatment can effectively eliminate the oxygen vacancies within the sample and force, improve the transmittance of the.7 samples in the visible range) the last light experiment is not ideal, analyzed the reason on the one hand may be ceramic sample thresholds, made of tiny pores and impurity of the second phase into light scattering and absorption in the heart, reduce the sample to 808nm the wavelength of incident light absorbed by another; may be the actual thickness of the sample is thinner, smaller than the wavelength of 808nm light intensity will enter the sample body absorption strength of 1/e, the length of the original, so that cannot produce enough energy to stabilize the emission wavelength of 1064nm laser.

【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ174.1

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