向氧化铝陶瓷中添加总量固定、但m(CuO)/m(TiO_2)不同的CuO-TiO_2复合助剂,研究其对氧化铝陶瓷烧结性能、微观结构以及物相组成的影响,揭示复合助剂的低温烧结机理.结果表明,CuO与TiO_2不易发生化合反应,分别以液相烧结和固相反应烧结...向氧化铝陶瓷中添加总量固定、但m(CuO)/m(TiO_2)不同的CuO-TiO_2复合助剂,研究其对氧化铝陶瓷烧结性能、微观结构以及物相组成的影响,揭示复合助剂的低温烧结机理.结果表明,CuO与TiO_2不易发生化合反应,分别以液相烧结和固相反应烧结来促进氧化铝陶瓷的致密化进程;TiO_2与Al_2O_3反应生成Al_2Ti_7O_(15)的固相烧结,比CuO的液相烧结更能有效地促进陶瓷的晶粒生长与致密化.在TiO_2固相烧结的基础上适当引入CuO液相,能够最大程度地降低氧化铝陶瓷的烧结温度;当在50 g Al_2O_3粉体中添加总量为0.025 mol的CuO-TiO_2复合助剂,并使m(TiO_2)/m(CuO+TiO_2)为0.80时,氧化铝陶瓷在1250℃烧结后其密度达到理论密度的98%以上.展开更多
Ce3＋-activated yttrium aluminum garnet （YAG） was prepared by the solid-state reaction, in which H3BO3, LiF, NaF, KF and BaF2 were used as the fluxes. The effect of fluxes on optical properties of phosphors was stud...Ce3＋-activated yttrium aluminum garnet （YAG） was prepared by the solid-state reaction, in which H3BO3, LiF, NaF, KF and BaF2 were used as the fluxes. The effect of fluxes on optical properties of phosphors was studied in detail, especially the fluxes of alkali fluorides, which could enhance the emission intensity and change the wavelength of emission peaks. Among these YAG：Ce phosphors, the phosphor sintered with H3BO3 and NaF exhibited the strongest emission. The emission peaks of phosphors prepared with fluxes from LiF to KF were shifted to long wavelength. The effect of NaF concentration on the emission intensity of YAG：Ce was also investigated. The value of emission intensity reached the maximum when the concentration of NaF was 0.5%.展开更多
采用熔融冷却法制备ZrO_2掺杂的CaO–Al_2O_3–SiO_2(CAS)系玻璃,通过差热分析仪、紫外可见光分光光度计以及电子万能试验机探讨了ZrO_2掺杂量对玻璃热稳定性、网络结构以及机械性能的影响规律。结果发现:当ZrO_2摩尔分数小于4%时,CAS...采用熔融冷却法制备ZrO_2掺杂的CaO–Al_2O_3–SiO_2(CAS)系玻璃,通过差热分析仪、紫外可见光分光光度计以及电子万能试验机探讨了ZrO_2掺杂量对玻璃热稳定性、网络结构以及机械性能的影响规律。结果发现:当ZrO_2摩尔分数小于4%时,CAS系玻璃的热学性能更加稳定,光学带隙随着ZrO_2掺杂量的增加而减小,结构更加致密完整,其体积密度、氧原子堆积密度以及弯曲强度均随着ZrO_2含量的增加而上升;当ZrO_2掺杂量超过4%后,该玻璃体系的热学性能、结构稳定性和力学性能均随着ZrO_2含量的增加而出现下降;当ZrO_2掺杂量为4%时,玻璃的光学带隙值达到3.28 e V,析晶温度Tx与玻璃转变温度Tg差值达到230.12℃,同时弯曲强度达到83.67 MPa。适量的掺杂ZrO_2,能够提高氧原子堆积密度、增强其网络结构,从而显著提高玻璃的结构稳定性和机械性能。展开更多
文摘向氧化铝陶瓷中添加总量固定、但m(CuO)/m(TiO_2)不同的CuO-TiO_2复合助剂,研究其对氧化铝陶瓷烧结性能、微观结构以及物相组成的影响,揭示复合助剂的低温烧结机理.结果表明,CuO与TiO_2不易发生化合反应,分别以液相烧结和固相反应烧结来促进氧化铝陶瓷的致密化进程;TiO_2与Al_2O_3反应生成Al_2Ti_7O_(15)的固相烧结,比CuO的液相烧结更能有效地促进陶瓷的晶粒生长与致密化.在TiO_2固相烧结的基础上适当引入CuO液相,能够最大程度地降低氧化铝陶瓷的烧结温度;当在50 g Al_2O_3粉体中添加总量为0.025 mol的CuO-TiO_2复合助剂,并使m(TiO_2)/m(CuO+TiO_2)为0.80时,氧化铝陶瓷在1250℃烧结后其密度达到理论密度的98%以上.
基金supported by the Science Technology Project of Zhejiang Province (2008C21153)the National Natural Science Foundation of China (60508014 and 50772102)+1 种基金Program for New Century Excellent Talents in University (NCET-07-0786)the Nature Science Foundation of Zhejiang Province (R406007)
文摘Ce3＋-activated yttrium aluminum garnet （YAG） was prepared by the solid-state reaction, in which H3BO3, LiF, NaF, KF and BaF2 were used as the fluxes. The effect of fluxes on optical properties of phosphors was studied in detail, especially the fluxes of alkali fluorides, which could enhance the emission intensity and change the wavelength of emission peaks. Among these YAG：Ce phosphors, the phosphor sintered with H3BO3 and NaF exhibited the strongest emission. The emission peaks of phosphors prepared with fluxes from LiF to KF were shifted to long wavelength. The effect of NaF concentration on the emission intensity of YAG：Ce was also investigated. The value of emission intensity reached the maximum when the concentration of NaF was 0.5%.
文摘采用熔融冷却法制备ZrO_2掺杂的CaO–Al_2O_3–SiO_2(CAS)系玻璃,通过差热分析仪、紫外可见光分光光度计以及电子万能试验机探讨了ZrO_2掺杂量对玻璃热稳定性、网络结构以及机械性能的影响规律。结果发现:当ZrO_2摩尔分数小于4%时,CAS系玻璃的热学性能更加稳定,光学带隙随着ZrO_2掺杂量的增加而减小,结构更加致密完整,其体积密度、氧原子堆积密度以及弯曲强度均随着ZrO_2含量的增加而上升;当ZrO_2掺杂量超过4%后,该玻璃体系的热学性能、结构稳定性和力学性能均随着ZrO_2含量的增加而出现下降;当ZrO_2掺杂量为4%时,玻璃的光学带隙值达到3.28 e V,析晶温度Tx与玻璃转变温度Tg差值达到230.12℃,同时弯曲强度达到83.67 MPa。适量的掺杂ZrO_2,能够提高氧原子堆积密度、增强其网络结构,从而显著提高玻璃的结构稳定性和机械性能。
