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Densified SiC ceramics were prepared by using gel-casting method combined with liquid-phase sintering (LPS). In this study, a low-toxicity gel-casting system based on 2-hydroxyethyl methacrylate (HEMA) and N, N′-methylene acrylamide (MBAM) as monomer and crosslinker respectively, was first applied to SiC fabrication. The effects of the processing parameters on gel-casting were investigated in detail to achieve optimized rheological behavior and green body strength. The best result was obtained in the slurry with solid content of 50 vol%, dispersant of 0.4 wt% and monomer/crosslinker ratio of 20 at pH10. With the modified ternary sintering aids (Al 2 O 3 –Y 2 O 3 –CeO 2) added, the densification can be realized at low temperature. After pressureless sintering at 1850 °C for 2 h, the sample with best mechanical properties was obtained. The highest relative density, hardness, flexural strength and fracture toughness were 96.23%, 24.94 GPa, 423.95 MPa and 4.78 MPa/m1/2, respectively. Present work provides an environmentally friendly and energy-saving process for preparing SiC ceramics with excellent properties. [ABSTRACT FROM AUTHOR]

High-brightness laser lighting requires high luminous efficacy and high thermal performance of luminescent materials. In this study, we designed and fabricated single-phase YAG:Ce ceramics with differential grain sizes by combining the coarse commercial phosphor and fine powder of precusor. The large YAG:Ce grains mainly contribute to excellent luminescence properties. The small YAG:Ce grains not only change the direction of light propagation to improve the luminous efficiency but also effectively increase the Ce3+ content to improve the absorption of blue light, which significantly further enhance the luminescence properties compared with the second phase in the YAG:Ce-base composite ceramics. The luminescent ceramic with 40 wt% large grains sintered under 1550 °C has the highest luminous efficacy of 398.5 lm/W. Compared with the Al 2 O 3 –YAG:Ce composite ceramic, the single-phase YAG:Ce ceramic effectively increased the absorption of blue light to enhance the luminescence properties without the adverse effects caused by the transverse scattering of light in the Al 2 O 3 phase. After encapsulating the ceramic onto a radiator, a high luminous flux of 7697.6 lm under the blue-laser excitation of 3.0 A (54.6 W) was obtained. These indicated its broad application prospects in high-power solid-state laser lighting. [ABSTRACT FROM AUTHOR]