电感耦合等离子体质谱法测定镍基单晶高温合金中痕量稀土元素

镍基单晶高温合金中稀土元素的含量会对其热学性能和稳定性能产生重要影响,因此需要对其中稀土元素进行准确监控和严格测定。采用3 mL盐硝混酸(盐酸与硝酸体积比为5∶1)-1.5 mL过氧化氢溶解镍基单晶高温合金样品,以Sr为内标对Sc进行校正,以Rh为内标对La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu、Y进行校正,用基体匹配法绘制校准曲线克服基体效应,以氦气作为碰撞气采用碰撞池反应模式消除轻质稀土元素所形成氧化物、氢氧化物离子对重质稀土元素¹⁵³Eu、¹⁵⁷Gd、¹³⁶Dy、¹⁶⁶Er的干扰,实现了电感耦合等离子体质谱法(ICP-MS)对镍基单晶高温合金中痕量稀土元素的测定。在优化的实验条件下,校准曲线线性相关系数均达到了0.999以上,线性范围为4~100 ng/mL,方法检出限为0.013~0.027 μg/g,定量限为0.04~0.09 μg/g。将实验方法应用于镍基单晶高温合金实际样品中稀土元素的测定并进行加标回收试验,测定结果的相对标准偏差(RSD,n=7)不大于5.6%,回收率为94%~106%。

Determination of trace rare earth elements in nickel-based single crystal superalloy by inductively coupled plasma mass spectrometry

The contents of rare earth elements in nickel-based single crystal superalloy have an important influence on its thermal properties and stability. Therefore, it is necessary to monitor and determine the rare earth elements accurately. The nickel-based single crystal superalloy sample was dissolved with 3 mL of hydrochloric acid-nitric acid mixture (the volume ratio of hydrochloric acid and nitric acid was 5∶1) and 1.5 mL of hydrogen peroxide in experiments. Sr was selected as internal standard to correct Sc. Rh was selected as internal standard to correct La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y. The standard curve was prepared by matrix matching method to overcome the matrix effect. Helium was used as collision gas, and the interference of oxides and hydroxide ions formed by light rare earth elements on heavy rare earth elements (including ¹⁵³Eu, ¹⁵⁷Gd, ¹³⁶Dy and ¹⁶⁶Er) was eliminated using the collision cell reaction mode. A method for the determination of trace rare earth elements in nickel-based single crystal superalloy by inductively coupled plasma mass spectrometry (ICP-MS) was established. Under the optimum experimental conditions, the linear correlation coefficients of the calibration curves were all above 0.999. The linear range was 4-100 ng/mL. The limit of detection was 0.013-0.027 μg/g, and the limit of quantification was 0.04-0.09 μg/g. The proposed method was applied to the determination of rare earth elements in actual sample of nickel-based single crystal superalloy. Moreover, the spiked recovery tests were conducted. The relative standard deviations (RSD, n=7) of determination results were not more than 5.6%, and the spiked recoveries were between 94% and 106%.