“Heavy atom substitution” was utilized to improve the thermal behaviors of Ce:LuAG transparent ceramics via Sr2+/Si4+ doping, exhibiting high luminous efficiency of radiation (261.98 lm W−1) and high luminance saturation threshold (∼65 W mm−2).

Composite ceramic phosphor (CCP) is a candidate light-conversion material to obtain the high-quality laser lighting source. Phosphors based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal stability. In this study, a novel composite structure ceramic was designed, including Al2O3–YAG:Ce/YAG layered ceramic with a size of 1 mm × 1 mm for lighting, and Al2O3 ceramic (φ = 16.0 mm) was used as the wrapping material due to its outstanding thermal stability. The prepared ceramics exhibited excellent thermal performance and no yellow ring phenomenon. Through this design, we achieved the match of the intensity distribution of the blue and yellow lights, resulting in a high angular color uniformity of 0.9 with a view angle of ±80°. All ceramics showed no luminous saturation phenomenon, even the laser power density was increased up to 47.51 W/mm2. A high-brightness white-light source with a luminous flux of 618 lm, a luminous efficiency of 126 lm/W, a CCT of 6615 K, and a CRI of 69.9 was obtained in the transmissive configuration. In particular, the surface temperature of the ceramic was as low as 74.1 ℃ under a high laser radiation (47.51 W/mm2). These results indicate that Al2O3/Al2O3–YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.

Optical scattering centers in transparent magnesium aluminate spinel (MgAl2O4) ceramics substantially limit their applications in infrared domes or transparent windows. In this study, hot isostatic pressing (HIP) sintering was employed to fabricate high-quality transparent MgAl2O4 ceramics without the addition of sintering additive, and revealed that dispersion behavior of starting powders was crucial to the quality of MgAl2O4 ceramics. Microstructural evolution and optical quality of MgAl2O4 ceramics as the function of ball milling speed and pre-sintering temperature were systematically investigated. Despite increasing ball milling speed moderated powder agglomeration, large voids were still observed from the depth direction of the sintered ceramics. These voids could be further eliminated by employing PEI as the dispersant, and the in-line transmittance of the resulting ceramic was 86.5% at 800 nm, which was almost identical to the theoretical limit of MgAl2O4.

Zr4+ ion doping is an effective method to enhance the optical and mechanical qualities of Y2O3 transparent ceramics. In most previous studies, slowing down densification and inhibiting grain growth of Y2O3 ceramic are generally recognized as the primary function of Zr4+ additive during sintering. In this work, an interesting simultaneous precipitation phenomenon of Zr4+ and Y3+ ions was discovered and it directly led to the refinement of precursors and Y2O3 powders. Consequently, the acting mechanisms of Zr additive should be demonstrated as the synergistic effect of refining precursor, producing oxygen interstitial and promoting solute-drag. Microstructure evolution and optical quality of Zr doped Y2O3 ceramics were further investigated in detail. By doping 3.0 at.% Zr4+ ions, Y2O3 transparent ceramics with a transmittance as high as 82.3% at 1064 nm could be realized, after sintering at 1775 degrees C for 8h in vacuum. In general, this essential synergistic effect should be adequately considered in the preparation of heterogeneous ion doped transparent ceramics using the coprecipitation method.

透明陶瓷是一种具有广阔应用前景的无机非金属材料,但以粉末烧结为主的传统制备策略存在依赖高质量原料粉体、需要长时间高温处理、设备和工艺复杂、生产成本高等技术限制.玻璃晶化法是通过调控晶化过程实现玻璃全部结晶并且获得透明陶瓷的新方法,因其可以克服与传统透明陶瓷加工相关的技术困难,并在合成高致密度、无气孔、非立方相、纳米结构透明陶瓷等方面具有独特的优势,而受到人们的广泛关注.本文首先从玻璃晶化法制备氧化物透明陶瓷的工艺方法和组分体系两方面入手,详细概述了该方法的发展历程和研究现状.接着,指出了目前研究中存在的问题,并对其未来发展前景进行了展望,以期该方法能够广泛应用于制备下一代高性能透明陶瓷材料.

Ceramic phosphors are widely considered the next-generation phosphor material for white LED/LD lighting, and a wide spectrum is a key factor in improving the CRI of lighting sources. In this paper, a novel, to our knowledge, barcode-structured YAG:Ce/YAG:Ce,Mn ceramic phosphor was designed and fabricated. The lighting sources with the CRI value of 73.5 and 68.9 were obtained under the excitation of blue LEDs and blue LDs, respectively. Simultaneously, thanks to the effective supplementary emission from a red LD, the CRI of the ceramic-based lighting source reached 81.8 under blue LD excitation. Specifically, the microstructure and luminescent property of ceramic phosphors with different thicknesses and ion doping concentrations were systematically studied. Besides, by changing the blue power from 0.52 W to 2.60 W, the CCT of the laser lighting source with the encapsulation of optimized YAG:Ce/YAG:Ce,Mn ceramic phosphors ranged from 3928 K to 5895 K, while the CRI always maintained above 80. The above results indicate that barcode-structured Ce:YAG/Ce,MnYAG ceramic phosphor is a candidate to achieve a high CRI and ican be applied to various lighting occasions.