火焰式原子吸收光譜法、過碘酸分光光度法及高硫酸銨-亞砷酸鈉滴定法測定鎳基超合金之錳含量

本實驗比較以儀器分析法(包活火焰式原子吸收光譜法、過碘酸分光光度法)及化學分析法(高硫酸銨-亞砷酸鈉滴定法)測定鎳基超合金標準參考物質IN 718及Hastelloy X中錳含量的優缺點。鎳基超合金由十多種元素所組成，其中含有0.001-1.00 wt% 的猛。在分光光度法和滴定法中，由於鉻的存在，低價位的猛價位的猛離子無法氧化成正七價之高錳酸根離子，因此須加入過氯酸及鹽酸使鉻揮發或是加入氧化鋅使其形成沉澱物而將鉻去除。前者有較好的再現性。滴定法的主要困難在於終點的判斷和樣品溶液的安定性。需經由多次實驗方能找出正確之滴定終點且樣品溶液配置完成後應立刻進行滴定。然而以過碘酸展色之樣品溶液，則在二十四小時內仍可維持其安定性。火焰式原子吸收光譜法除提供較佳之精密度外，還具低基質干擾之優點，因此不須繁雜的去鉻前處理步驟。這三種方法都提供良好的準確度。

關鍵字

鎳金超合金；錳；火焰式原子吸收光譜法；過碘酸分光光度法；高硫酸銨-亞砷酸鈉滴點法

並列摘要

This work gives a comparison between the instrumental analysis including flame atomic absorption spectrometry (FAAS) and periodate spectrophotometry and chemical analysis, namely, peroxidisulfate-arsenite titrimetric method for the determination of manganese in the standard reference materials of nickel-base superalloys. Nickel-base superalloys studied including Inconel 718 and Hastelloy X, contained 0.100-1.00 wt. % Mn in addition to other concomitants. In the spectrophotometric and titrimetric methods, divalent manganate failed to be oxidized to the permanganate in the presence of chromium. Therefore, chromium was removed either by volatilization with perchloric acid and hydrochloric acid or by precipitation with zinc oxide. The former gave more reproducible results. In the tritrimetric method, several trials had to be done to picture a clear end-point. Futhermore, the titration had to be proceeded immediately after sample solutions were prepared whereas the color sample solutions prepare d in the spectrophotometric method were stable for at 24 hours. Beside offering better precision, there was no significant matrix effect when analysed with FAAS. Therefore, the tedious sample pretreatment for the removal of chromium was not required. All of these methods gave excellent accuracy.

並列關鍵字

Nickel-base superalloy ； Manganese ； Flame atomic absorption spectrometry ； Periodate spectrophotometry ； Peroxidisultate-arsenite titrimetric method

國際替代計量

火焰式原子吸收光譜法、過碘酸分光光度法及高硫酸銨-亞砷酸鈉滴定法測定鎳基超合金之錳含量

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