Synthesis Of Sialon Phosphors Prepared By Combustion Synthesis

SiAlON phosphors have attracted significant attention recently in both theresearch community and industrial field for the reason of unique emission properties(excitation band ranges from UV towards blue and emission band is controllable),outstanding chemical and thermal stabilities so that are highly applicable inhigh-power white LEDs.Combustion synthesis method is a low-cost and easily-used approach preparingSi-based nitride phosphors. Compared to the conventional solid-state reaction (SSR)method, it has advantages of low energy consumption,being friendly to environment,time-saving, low cost, simplefacilitiesandand loose productseasier for pulverization.In this thesis, Eu2+doped SiAlONphosphor was synthesized bycombustionsynthesis method. Post-annealing processes and characterization analysis were carriedon at the same time. Main research was on the combustion synthesized Eu2+dopedCa-α-SiAlON system. The optimal reaction conditions for the synthesis under specificsolid phase design and the effects of different solid phase design on the products wereexplored. Meanwhile, the optimal manufacturing process of Eu2+dopedβ-SiAlONphosphor was initially studied.First, specific solid phase design (stable point in phase diagram of Ca-α-SiAlON:m=1.6and n=0.84) was carried on for the optimal manufacturing parameters andreaction conditions. The results are as follows: different kinds of sources (Al, Si, Ca),proportion of combustible substances in the sources, porosity factor of rawmaterials,pressure of N2(g) and additives matters a lot to the phase-pure, morphologyand photoluminescence properties. By regulating the manufacturing parameters,Eu-doped Ca-α-SiAlON yellow phosphors with satisfactory phase-pure, crystallinity,morphology and photoluminescence properties (with an intense emission bandthatpeaks around585nm) were successfully synthesized. The manufacturing process issimple, cheap, and with promising industrial prospects.The influences of solid phase design parameters m, n and x to Ca-α-SiAlONyellow phosphors were then deeply studied. The optimal post-annealing conditions ofthe productions were investigated, including temperature, time and gas atmosphere.Through the comparisons between combustion synthesis method, solid-state reactionand direct nitridation with silicon powder under the same solid phase design,and the characterizations of the corresponding productions, we conclude that underthis solid phase design, the productions from combustion synthesis method show thebest phase purity, crystallinity and photoluminescence properties, especially with apost-annealing treatment.Finally, we choose a specific solid phase design (z=0.5), with different sourceproportions, N2(g) pressures and concentrations of the doped Eu2+, to initially explorethe optimal manufacturing conditions and the production’s properties of combustionsynthesized β-SiAlONphosphors. β-SiAlON green phosphorswith an intense emissionband thatpeaks at545nmwere successfully synthesized afterwards.