过氧化氢分光光度法测定镍钛铌合金中钛

镍钛铌合金是一种重要的功能材料,其中的钛含量对合金性能影响显著。实验以过氧化氢为显色剂,采用分光光度法测定镍钛铌合金中高含量钛。样品用稀硫酸溶解,加入过氧化氢在室温下形成黄色络合物,于410nm处测定吸光度。试验优化了酸度、过氧化氢用量、显色时间等影响体系显色的因素。在优化的试验条件下,钛质量浓量在70.0~80.0μg/mL范围内符合朗伯比尔定律,显色体系的表观摩尔吸光系数为1.5×10² L·mol^-1·cm^-1。样品溶液无需分取而直接测定,避免了稀释带来的误差。镍的本色干扰采用基体匹配法消除。按照实验方法测定两个镍钛铌合金样品中钛,测定结果的相对标准偏差(RSD,n=6)分别0.40%和0.30%,并与滴定法测定结果相一致。方法实现了镍钛铌合金中高含量钛的准确测定。

Determination of titanium in nickel-titanium-niobium alloy with hydrogen peroxide spectrophotometry

Nickel-titanium-niobium alloy is an important functional material, and the content of titanium significantlyaffects the properties of alloy. The high content titanium in nickel-titanium-niobium alloy was determined by spectrophotometry using hydrogen peroxide as coloring agent. The sample was dissolved with diluted sulfuric acid. Hydrogen peroxide was added at room temperature to react with titanium to form a yellow complex. The absorbance was measured at 410nm. The factors influencing the coloring of system were optimized including the acidity, the dosage of hydrogen peroxide and coloring time. Under the optimized testing conditions, the Beer's law was obeyed for the mass concentration of titanium in range of 70.0-80.0μg/mL, and the apparent molar absorptivity was 1.5×10² L·mol^-1·cm^-1. The sample solution could be directly determined, which avoided the error caused by dilution. The interference of nickel could be eliminated by matrix matching method. The contents of titanium in two Ni-Ti-Nb alloy samples were determined according to the experimental method. The relative standard deviation (RSD, n=6) of determination results was 0.40% and 0.30%, respectively. The determination results were consistent with those obtained by titration method. The proposed method was applied for the accurate determination of high content titanium in nickel-titanium-niobium alloy.