三价铈离子掺杂氯化钾的光致发光性能

采用水热蒸发法制备了KCl∶Ce3+荧光粉。测量并分析了材料在室温下的真空紫外激发光谱及相应的发射光谱。结果表明激发谱显示6个峰,峰位分别为149、194、206、219、233和251nm。其中149nm的激发峰是基质吸收引起的;194、206、219、233和251nm是Ce3+离子的4f→5d跃迁引起的。发射峰显示双峰结构,峰位分别是311和326nm。此峰对应于Ce3+离子的5d→4f(2F5/2,2F7/2)跃迁。

Study of microstructure and shear strength of Cu/AuSn20/Ni joints

The Cu/AuSn20/Ni(mass percent) joint was prepared by the reflow bonding process,and the microstructure and shear strength of the Cu/AuSn20/Ni joint were investigated.The results showed that,the solder formed a(Au5Sn+AuSn) eutectic microstructure after reflow at 300℃ for a short time,and the cellular-like(Au,Cu)5Sn intermetallic compound(IMC) was formed at the upper Cu/AuSn20 interface,while the flake-like(Ni,Au)3Sn2 IMC was formed at the lower AuSn20/Ni interface.Upon increasing the reflow time,more and more Cu(Ni) atoms from the subtrates diffused into the solder,resulting the shift of chemical composition of the solder.So that the(Au,Cu)5Sn phase at the upper Cu/AuSn20 interface transformed into the ζ(Cu) solid solution.The(Ni,Au)3Sn2 phase at the lower AuSn20/Ni interface grew gradually to form a continuous IMC layer.The eutectic microstructure in the solder vanished and the final microstructure of Cu/AuSn20/Ni joint was composed of the ζ(Cu) solid solution and(Ni,Au)3Sn2 IMC layer.The shear strength of the Cu/AuSn20/Ni joint increased slightly with the increasing of the reflow time.