高质量YAG基透明陶瓷的制备技术与性能分析
文献类型：学位论文
| 作者 | 易学专 |
| 学位类别 | 硕士 |
| 答辩日期 | 2014 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 周圣明 |
| 关键词 | Ce:YAG透明陶瓷 Ce: YAG/ MgAl2O4复合透明陶瓷 白光LED 荧光 |
| 其他题名 | Fabrication and performance analysis of high quality YAG-based transparent ceramic |
| 中文摘要 | 钇铝石榴石YAG具有优异的热学、光学和机械性能，是一种应用广泛的稀土离子掺杂基质材料。在高温窗口、激光材料、荧光材料等领域都有着非常重要的应用。尤其是纯YAG在高温窗口领域的的应用近年来备受关注，YAG透明陶瓷在高温窗口领域性能不亚于蓝宝石，同时要明显优于局限于1100℃以下工作的石英。然后蓝宝石也受限于成本高，生长周期长的问题，这使得YAG透明陶瓷在高温窗口领域有一定的市场前景。 白光LED由于其本身使用寿命长，高效的等优势被广泛研究。当前使用最广泛的LED封装方式就是在商用蓝光LED芯片上面涂覆一层Ce:YAG荧光粉硅胶，一部分蓝光经荧光粉转换为中心波长在530nm的黄光，剩余部分的蓝光透射出来与黄光通过混色原理得到白光。然而有机硅胶热导率差，在高温下容易老化变形，这将会使得LED灯具的光效和色坐标都恶化。另一方面随着社会对大功率LED的需求，LED芯片的发热进一步明显。这种情况下将逐步暴露出传统封装方式的缺点，这在一定程度上局限了荧光粉在高功率灯具上的应用。Ce：YAG荧光陶瓷可以充分克服以上限制因为它的荧光离子分布均匀，同时热导率高、机械强度好。故而在LED领域倍受关注。本论文以商业氧化物粉体为原料，采用固相反应和真空烧结技术制备高透明性纯YAG和Ce:Cr:YAG, Ce:Pr:YAG荧光陶瓷,以及Ce:Cr:YAG, Ce:Pr:YAG与MgAl2O4复相体系的透明陶瓷，并对材料性能表征测试。工作内容主要包括以下几点： 1、制备了164*55*15mm的大尺寸纯YAG透明陶瓷，并且通过纯YAG的制备来逐步改善工艺：对烧结温度，保温时间，球磨过程等工艺的优化，提高透明陶瓷质量。 2、制备了不同Ce浓度掺杂的YAG透明陶瓷，对其物相、显微结构进行了表征分析，并研究了其光谱性能，重点是考察Ce4+离子的抑制方法和相应的机理。 3、Ce:Cr:YAG, Ce:Pr:YAG荧光陶瓷制备工艺的优化，通过激发、发射光谱等光谱测试验证了Ce3+—Cr3+/Pr3+直接能量转移的存在，并深入研究Ce:Cr:YAG, Ce:Pr:YAG荧光陶瓷的红光补偿效应对改善色温和显色指数的意义。重点通过LED封装中的测试分析考察该体系荧光陶瓷在LED中的应用，与商业LED蓝光芯片封装实现了高品质的白光输出，最大光效达到了83lm/W,色温4905K,显色指数72. 4、制备了Ce: Pr: YAG/ MgAl2O4复合透明陶瓷，对比了两种不同工艺制备下的陶瓷物相、光学照度。其光学照度要优于单相的Ce:YAG荧光陶瓷，是一种有市场前景的荧光陶瓷。 |
| 英文摘要 | Yttrium aluminum garnet (YAG) is an outstanding matrix for rare earth ions due to its excellent mechanical, optical and thermal properties, and it has been widely used in the field of high-temperature window, laser materials and fluorescent materials. Especially in the field of high-temperature window, the performance of YAG transparent ceramics has the similar performance with sapphire, and is much better than quartz which can be only used in a temperature below 1100℃. However, the use of sapphire has been limited because of its high cost and long production cycle. YAG transparent ceramic high-temperature window may have a large market in the future. White LEDs have been deeply investigated due to their advantages of long lifetime and high efficiency. The current leading commercial white LED is a combination of blue LED and yellow phosphor packed with organic resins. A portion of the blue light from the blue chip is converted to a broad spectrum centered at about 530nm by the Ce:YAG phosphor. Then the remainder blue light combined with yellow light gives the white light. As we all know, organic resins have poor thermal conductivity and easily get deteriorated at high temperature, which will cause the degradation of luminous efficacy (LE) and the alteration of emission color. The temperature of LED-chip is increasing as the increase of its output power. So the use of traditional encapsulation may be limited in high power applications. Y3Al5O12 transparent ceramic doped with Ce3+ exhibits the advantages of excellent mechanical, optical and thermal properties.And soon become widely used in White LED. In this paper Ce:YAG, Ce,Cr/Pr:YAG:YAG transparent ceramics were fabricated by solid-state reaction and vacuum sintering method using commercial Al2O3, Y2O3 ,Cr2O3 ,Pr6O11 and CeO2 as raw materials. The main contents of this paper are as follows, 1. Large-size of 164*55*15mm YAG transparent ceramic samples were prepared. The fabrication process has been improved through the preparation of YAG. Such as the holding temperatures, temperature ramping rates, ball milling etc. 2. YAG transparent ceramics doped with different concentrations of Ce were synthesized. The phase purity, spectral properties and microscopic structure were characterized. This chaper focuses on how to suppress the Ce4+ ions, as well as investigate the mechanism. 3. The Ce,Cr/Pr:YAG:YAG transparent ceramics were fabricated. The energy transfer process was proved by the excitation, emission spectra. And in-depth studied the red light compensation effect, which has positive significance to improve the color temperature and color rendering index. High quality white light was obtained when the Ce,Cr/Pr:YAG ceramic was directly combined with commercial blue LED chip. A maximum luminous efficacy exceeding 83lm/W, color rendering index of 72, at a low correlated color temperature of 4905K was obtained. 4. The Ce:YAG/MgAl2O4 transparent ceramics were fabricated. The ceramic phase and optical illumination were compared under two different fabrication methods. The Optical illumination of Ce:YAG/MgAl2O4 is superior to Ce: YAG phosphor ceramics, which may has great market prospects. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16840]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 易学专. 高质量YAG基透明陶瓷的制备技术与性能分析[D]. 中国科学院上海光学精密机械研究所. 2014. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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