材料期刊网

碳化钨是一种由钨和碳组成的深灰色化合物粉末，常应用于生产各类硬质合金。为了消除颗粒效应，实验采用熔融方法制样，因碳化钨不能直接熔融，故先将碳化钨氧化成三氧化钨，按稀释比1∶10加入混合熔剂[m（Li2B4O7）∶ m（LiBO2）＝67∶33]，加0.25 mL 500 g／L溴化锂溶液为脱膜剂，高频熔样机1050℃熔融14 min ，制备三氧化钨的熔融玻璃片。建立了X射线荧光光谱仪（XRF）测定碳化钨粉中铁含量的分析方法。在无合适含铁的碳化钨及三氧化钨标样的情况下，采用在三氧化钨基体中加入铁标准溶液（硝酸介质）的方式配制标样，采用变动的理论α影响系数法校正基体效应，校准曲线在铁质量分数0.01％～0.30％范围内相关系数为0.999。对三氧化钨标准样品进行分析，测定值与认定值一致；对碳化钨实际样品进行分析，铁的测定结果同国家标准的分光光度法一致，相对标准偏差（RSD ，n＝7）小于4.0％。

Tungsten carbide is a kind of deep grey compound powder composed of tungsten and carbon .It is usually used in the production of various kinds of hard alloys .The sample was prepared by fusion method to eliminate the granular effect .Since tungsten carbide could not be directly fused ,it was firstly oxidized to tungsten trioxide .For the preparation of tungsten trioxide fused bead ,the mixed flux [m(Li2 B4 O7 )∶m(LiBO2 )=67∶33] was added with dilution ratio of 1∶10 ,0.25 mL of 500 g/L lithium bromide solution was added as the remover ,and fusion by high frequency fusion machine at 1 050 ℃ for 14 min .The analy‐sis method of iron in tungsten carbide powder by X‐ray fluorescence spectrometry (XRF) was established . In case of lacking appropriate certified reference materials of tungsten trioxide or carbide tungsten contai‐ning iron ,the calibration sample was prepared by adding iron standard solution (in nitric acid medium) in‐to tungsten trioxide substrate .The matrix effect was corrected by variable theoretical α influence coeffi‐cient method .The correlation coefficient of calibration curve was 0.999 when the mass fraction of iron was in range of 0.01%‐0.30% .The certified reference material of tungsten trioxide was analyzed ,and the found results were consistent with the certified values .The actual tungsten carbide sample was also ana‐lyzed ,and the found results of iron were consistent with those obtained by spectrophotometry in national standard method .The relative standard deviation (RSD ,n=7) was less than 4.0% .