SPS烧结对磷酸镧晶体取向及热导率的影响

Effect of SPS on Crystal Orientation and Thermal Conductivity of LaPO_4

以放电等离子体烧结(SparkPlasmaSintering:SPS)技术制备了相对密度较高的磷酸镧(LaPO4)陶瓷,利用X射线衍射(XRD)分析了不同压力对LaPO4陶瓷晶体取向的影响,并测得在1350℃,40MPa下保温3min样品从室温到1473K的热导率,结果表明:利用SPS制备的LaPO4陶瓷出现了较为明显的织构,其(200)晶面与(120)晶面XRD衍射峰积分面积的比值由无压烧结时的0.5989增加到SPS烧结压力为50MPa时的2.2409,所测热导率随温度升高迅速降低,在高温又有所回升,其中室温热导率较无压烧结时低。

LaPO4 ceramics with high relative density was prepared by spark plasma sintering （SPS） methods. X-ray diffraction （XRD） was used to characterize the effect of pressure on crystal orientation of LaPO4, The temperature dependence of thermal conductivity of LaPO4 at 1350 ℃ under 40 MPa for 3 min was also obtained. Results reveal that the evident crystal orientation of LaPO4 can be found by SPS technique, and the integral arearatios of （200） and （120） diffraction peak increase from 0.5989 of pressureless sintering to 2.2409 of SPS under 50 MPa. The thermal conductivity of the ceramics decreases extremely with increasing the temperature, having a little enhancement at high temperature, and it is lower than that of pressureless sintering at room temperature.