固相法合成La_2Ni_(0.5)M_(0.5)O_(4+δ)(M=Co,Cu)材料及电性能(英文)

Electrical performances of La_2Ni_(0.5)M_(0.5)O_(4 +δ)( M=Co ,Cu)with K_2NiF_4-type structure synthesized by conventional solid state route

使用金属氧化物La2O3,NiO,CuO和Co2O3作为原料，固相反应法能够合成出具有K2NiF4型结构单一相的、且晶粒尺寸在35-50nm范围的La2Ni0.5M0.5O4＋δ（M=Co，Cu）粉料，用XRD、SEM和直流四极探针电导测试法研究了合成La2Ni0.5M0.5O4＋δ（M=Co，Cu）粉料的煅烧工艺条件和掺杂元素对电性能的影响以及粉料的颗粒形貌。随着煅烧温度的升高和保温时间的延长，晶粒尺寸在不断长大；合成的粉料在1300℃烧结5h后所有样品的电导率在空气条件下于100-800℃范围内都在增加。掺杂Co或Cu后的材料LaNiO4＋δ的电导率均有增加，但掺杂Co后材料电导率要大于掺杂Cu的电导率。为此确定La2Ni0.5M0.5O4＋δ（M=Co，Cu）类粉料固相法合成的适宜煅烧条件为1400℃下保温时间14h。

The powders of single phase perovskite-like La2Ni0.5M0.5O4＋δ（M=Co, Cu） with K2 NiF4-type structure and the crystalline grain sizes in the range of 35-50nm, have been synthesized by conventional solid state reaction methods using La2O3 ,NiO, CuO and Co2O3 as starting materials. The effects of the calcinations process and doped elements on the electrical performances and the particle morphology of La2Ni0.5M0.5O4＋δ（M=Co,Cu） were investigated with XRD, SEM and conventional DC four-probe measurement technologies. The crystalline grain sizes in La2Ni0.5M0.5O4＋δ（M=Co,Cu）, and the electrical conductivity of all samples sintered 1300℃ for 5h from 100-800℃ in air gradually increase with the increasing of calcined temperature and the extending of holding time. The electrical conductivity even increase after dopping element Co or Cu for M in La2Ni0.5M0.5O4＋δ but the electrical conductivity of Co-doped materials is higher than that of the Cu-doped. Therefore it is ascertained that the optimal fabricating process for the series of La2Ni0.5M0.5O4＋δ（M=Co,Cu） powders is at 1400℃ for 14 h.