氧化镍(绿镍矿)等温压缩及高压相变研究  

ISOTHERMAL COMPRESSION AND HIGH PRESSURE PHASE TRANSFORMATION OF NICKEL OXIDE (BUNSENITE)

作　　者：熊大和[1] 

机构地区：[1]中国科学院地质研究所

出　　处：《高压物理学报》1991年第3期169-176,共8页Chinese Journal of High Pressure Physics

摘　　要：本文采用DAC(金刚石压砧高压腔)装置,对氧化镍进行了静水压、非静水压、电导率测量等系统高压实验,获取了氧化镍等温压缩、高压相变及电导率压力效应的新结果,并在实验数据的基础上,对其高压相变与电性及磁性变化关系及体弹模量作了分析讨论。Nickel Oxide(NiO,Bunsenite)has been used as an analogue modeling composition in relation to other monoxide as MgO,FeO of earth interior. Crystal structure change of NiO from NaCl type fee to rhombohedral was discovered by Rooksby in 1943 at low temperature - 183℃. We recently carried out experiments under high pressure to 12. OGPa using diamond anvil cell with liquid pressure transmitting medium and direct compression to 29GPa. Our experimental results show the isothermal compression of NiO under pressures from 1. 22GPa to 8. 87GPa,lattice parameters and molal volume. At zero pressure:a0 = 0. 41824nm;Vm= 11. 0099×10-3nm3; density ,6. 7802g/cm3andat8. 87GPa;a = 0. 41139nm;Vm= 10. 4819×10-3nm3 (density ,7. 1254g/cm3. All data show a small deviation from Drickamer and S. K. AgrawaPs results. The diffraction lines(111), (220) of NiO suddenly splitting until pressure loading up to 12GPa at hydrostatic compression. Phase change of NiO from cubic to rhombohedral. The same results obtained by direct compression at pressure to 5. 8 GPa and up to 29GPa. Lattice parameter of rhomb. newphasea=0. 29670nm ;c= 0. 70000nm ,Vm = 1 0. 7084× 10-3nm3; density ,6. 9726g/cm3,this date agree with Rooksby' s a=0. 29660nm. The magnetic properties of NiO vary with pressure change Neel temperature of NiO 250℃(523K) ,decreases,when pressure increases, whereas below Neel temperature NiO changed in antiferromagnetic and rhombohedral crystal structure. Calculation bulk modulus of NiO by Birch-Manghnahan equation best fits to the p-V data and assuming K'o values of 4, give K'o = 166. 83GPa. Molal volume vs bulk modulus shows the compressibility of NiO is approching to MgO.

关 键 词：氧化镍 高压相变 等温压缩 电导率 

分 类 号：P578.4[天文地球—矿物学]