Blue-to-Orange Tunable Luminescence from Europium Doped Yttrium--Silicon--Oxide--Nitride Phosphors

Europium-doped yttrium-silicon-oxide-nitride phosphors are synthesized by carbothermal reduction and nitridation method. The crystal structure of the phosphors changed gradually from oxide Y2Si2O7 to nitride YSi3N5 state with increasing dosage of Si3N4 and carbon powder. The Y2Si2O7：Eu phosphor shows a blue emission at 465 nm with 300 nm excitation and a characteristic red emission of Eu^3＋ at 612 nm with 230 nm excitation. The YSi3N5：EU phosphor shows a broad emission band centred at 595nm with some sharp peaks of Eu^3＋ with 325nm excitation. The absorption of the studied phosphors increases from 450 to 700hm with an increment in nitrogen content. Blue-to-orange tunable luminescence is observed with 390 nm excitation.     

高温合成锰酸锶镧的缺陷

严格按照化学式拟定配方,采用固相合成方法合成的锰酸锶镧材料中含有杂相La2O3.借助XRD,DSC,TG等分析手段分析了高温合成锰酸锶镧的缺陷,尝试对锰酸锶镧进行高温再处理,结果获得的纯锰酸锶镧不含La2O3杂相.     

掺杂CaCO3及B4C对铬酸镧陶瓷连接体的影响

铬酸镧(LaCrO3)材料具有良好的高温化学稳定性与物理稳定性,被认为是理想的高温电解制氢的连接体隔板材料,然而其高温下电导性能的主要影响因素仍有待研究。采用固相法合成掺杂CaCO3和B4C铬酸镧粉体,并研究了掺杂量对铬酸镧陶瓷的烧结性能、电阻率的影响。应用X射线衍射(XRD)、扫描电子显微镜(SEM)、四探针法和排水法分析了铬酸镧连接体的结构、微观形貌、晶相组成、电阻率以及密度。研究表明:加入CaCO3,B4C能够促进晶粒细化,但B4C的加入不利于铬酸镧陶瓷致密化烧结。加入CaCO3能降低材料电阻率,B4C的加入可能改变晶界电阻,从而对陶瓷的电阻率形成影响。CaCO3=20%,B4C=0.1%(摩尔分数)配比的铬酸镧作为连接体材料,高温下具有较低且稳定的电阻率。