Growth and morphology of neodymium or ytterbium doped calcium gadolinium yttrium oxoborate (Re∶Ca 4Gd x Y 1- x O(BO 3) 3(Re∶GdYCOB)Re =Nd,Yb; x =0-1)were systematically studied. Polycrystalline materials used for Re...Growth and morphology of neodymium or ytterbium doped calcium gadolinium yttrium oxoborate (Re∶Ca 4Gd x Y 1- x O(BO 3) 3(Re∶GdYCOB)Re =Nd,Yb; x =0-1)were systematically studied. Polycrystalline materials used for Re∶GdYCOB single crystals growth were synthesized by multistage solid phase reaction method.Re∶GdYCOB single crystals were grown by Czochralski technique.The pulling rates are 0.5-2mm/h and the rotation rates are 10-30r/min.Usually 65-75% polycrystalline materials can be transformed into good quality single crystals under our growth conditions. The structures of some as grown Re∶GdYCOB single crystals were measured by using a four circle diffractometer.The results measured show that the space group of the crystals is C 3 s Cm.The determined lattice constants of 8 at% Nd doped Ca 4YO(BO 3) 3 single crystal are a =0.8076nm, b =1.6020nm, c =0.3527nm , β =101.23°.展开更多
采用氧化物固相法制备(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列负温度系数(Negative Temperature Coefficient,NTC)热敏陶瓷材料。利用热重-差热(TG-DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDS)、阻温特性以及...采用氧化物固相法制备(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列负温度系数(Negative Temperature Coefficient,NTC)热敏陶瓷材料。利用热重-差热(TG-DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDS)、阻温特性以及老化性能测试等手段,确定了材料粉体最佳煅烧温度,表征了陶瓷体物相、形貌、元素含量、电学性能、稳定性与Al2O3含量的关系。结果表明:(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列热敏陶瓷材料电阻率随着Al2O3含量增加显著增大,但材料常数B值增加平缓。当x=0.15时,该陶瓷材料呈现出低B(2816.44 K)、高阻(11893.89?·cm)的优良电学特性。热敏电阻经125℃老化500 h,阻值漂移(ΔR/R)均小于0.94%。展开更多
文摘Growth and morphology of neodymium or ytterbium doped calcium gadolinium yttrium oxoborate (Re∶Ca 4Gd x Y 1- x O(BO 3) 3(Re∶GdYCOB)Re =Nd,Yb; x =0-1)were systematically studied. Polycrystalline materials used for Re∶GdYCOB single crystals growth were synthesized by multistage solid phase reaction method.Re∶GdYCOB single crystals were grown by Czochralski technique.The pulling rates are 0.5-2mm/h and the rotation rates are 10-30r/min.Usually 65-75% polycrystalline materials can be transformed into good quality single crystals under our growth conditions. The structures of some as grown Re∶GdYCOB single crystals were measured by using a four circle diffractometer.The results measured show that the space group of the crystals is C 3 s Cm.The determined lattice constants of 8 at% Nd doped Ca 4YO(BO 3) 3 single crystal are a =0.8076nm, b =1.6020nm, c =0.3527nm , β =101.23°.
文摘采用氧化物固相法制备(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列负温度系数(Negative Temperature Coefficient,NTC)热敏陶瓷材料。利用热重-差热(TG-DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDS)、阻温特性以及老化性能测试等手段,确定了材料粉体最佳煅烧温度,表征了陶瓷体物相、形貌、元素含量、电学性能、稳定性与Al2O3含量的关系。结果表明:(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列热敏陶瓷材料电阻率随着Al2O3含量增加显著增大,但材料常数B值增加平缓。当x=0.15时,该陶瓷材料呈现出低B(2816.44 K)、高阻(11893.89?·cm)的优良电学特性。热敏电阻经125℃老化500 h,阻值漂移(ΔR/R)均小于0.94%。
