草酸盐重量法和电感耦合等离子体原子发射光谱法相结合测定钇铝合金中钇

钇铝合金中钇可显著改善合金的铸造性和抗蠕变性,准确测定钇铝合金中的钇量,对高性能铝合金材料的开发意义重大。以氢氧化钠溶液分解试料,经过滤分离铝,用盐酸溶解生成的氢氧化钇沉淀,在pH值为1.8~2.0的条件下,以草酸沉淀钇,经陈化、过滤、洗涤后,将沉淀于950℃灼烧至恒重,计算沉淀中钇量;滤液经硝酸、高氯酸处理后,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定滤液中钇含量;两部分测定结果加和即为钇铝合金中钇量。实验结果表明,以氢氧化钠溶液分解试料并过滤后,可以实现钇和铝的有效分离,再调节滤液至合适酸度,以草酸沉淀、过滤钇,可以达到钇与其他共存元素的分离,沉淀中残留的共存元素不干扰重量法测定钇,滤液中的共存元素不干扰电感耦合等离子体原子发射光谱法测定沉淀分离损失的钇。方法用于2个钇铝合金样品中钇的测定,结果的相对标准偏差(RSD,n=10)为0.49%~0.78%。按照实验方法对1个钇铝合金中钇进行加标回收试验,回收率为100%~101%。同时使用实验方法和碱溶-EDTA滴定法测定钇铝合金样品中钇,测定结果基本一致。

Determination of yttrium in yttrium-aluminum alloy byoxalate gravimetry and inductively coupled plasmaatomic emission spectrometry

The yttrium in the yttrium-aluminum alloy can significantly improve the castability and creep resistance of alloy. Therefore, the accurate determination of yttrium content in the yttrium-aluminum alloy is of great significance for the development of high-performance aluminum alloy materials. The yttrium-aluminum alloy sample was decomposed with sodium hydroxide solution. After separation of aluminum by filtration, the yttrium hydroxide precipitate was dissolved with hydrochloric acid. Then yttrium was precipitated with oxalic acid at pH 1.8-2.0. After ageing, filtration and washing, the precipitate was calcined at 950℃ until the weight was constant. The content of yttrium in precipitate was calculated. The filtrate was treated by nitric acid and perchloric acid, and the content of yttrium in filtrate was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The sum of two experiments was the content of yttrium in the yttrium-aluminum alloy. The experiment results showed that yttrium and aluminum could be effectively separated by decomposing the sample with sodium hydroxide solution followed by filtration. Then, the pH of filtrate was appropriately adjusted for the precipitation and filtration of yttrium with oxalic acid, realizing the separation of yttrium from other coexisting elements. The residual coexisting elements in precipitate had no interference with the gravimetric determination of yttrium. The coexisting elements in filtrate had no interference with the determination of yttrium (lost in precipitation separation process) by ICP-AES. The proposed method was applied for the determination of yttrium in two yttrium-aluminum alloy samples. The relative standard deviations (RSD, n=10) of determination results were between 0.49% and 0.78%. The spiked recovery tests of yttrium in one yttrium-aluminum alloy sample were conducted according to the experimental method. The recoveries were between 100% and 101%. Meanwhile, the content of yttrium in yttrium-aluminum alloy sample was also determined by alkali dissolution-EDTA titrimetry, and the results were basically consistent with those obtained by the experimental method.