摘要
由於Nb_2O_5与Ta_2O_5物理、化学性质相似,主体Nb_2O_5对Ta分析线强度干扰很大。因此,Nb_2O_5中光谱测定Ta_2O_5的灵敏度很差,为了提高Ta分析线强度,通常的光谱条件选择是无效的。实验表明在旋流气室中,采用高含量Ar的(Ar、O_2)控制气氛电弧激发,提高了Nb_2O_5中Ta_2O_5的光谱分析灵敏度。然而,由於Nb_2O_5在高温下易补被碳还原,虽然用Stallwood喷咀可以改善蒸发,减慢样品还原为碳化物,但是,为了进一步提高蒸发速率,使样品蒸发速度快补蒸发过程中样品在电极穴中的还原速率,最后采用N_2气控制电弧。采用本文提出的N_2-旋流室-直流电弧激发方法,使Nb_2O_5中Ta_2O_5的光谱分析灵敏度比(Ar、O_2)控制法提高5倍,比空气电弧法提高100倍。
Since Nb_2O_5 and Ta_2O_5 have very similar chemicaland pysical characteritics,the influence of matrixNb_2O_3 on Ta_2O_5 results in low sensitivity for tantalum.To increase the intensity of Ta spectral lines,it isineffective by changing operation conditions in normalway.It is experimentally shown that the analyticalsensitivity of Ta_2O_5 in Nb_2O_5 can be increased by useof a controlled atmosphere which includes a largeamount of Ar and small amount of O_2 and flowsthrough cyclone chamber. However,in this case theevaporation of sample is depressed due to reduction ofNb_2O_5 into involatile carbide. Although the evaporationcan be improved by Stallwood jet,it is preferred to use controlled N_2 atmoosphere -D.C. are excitationsystem to facilitate the evaporation. With thisexcitation system,the evaporation rate of the sampleis faster than the reduction rate of samole in theelectrode cave. In this way the analytica sensitivity ofTa_2O_5 in Nb_2O_5 is 5 times higher than that in themixed atmosphere of Ar and O_2,and 100 times higherthan that in air.
出处
《分析试验室》
CAS
CSCD
北大核心
1994年第6期72-75,共4页
Chinese Journal of Analysis Laboratory
关键词
氧化铌
氧化钽
光谱分析
灵敏度
Spectrogaphic analysis
contro-lled atmosphere
cyclone chamber
Ta_2O_5
Nb_2O_5 determination