Uncertainty evaluation for determination of niobium in IN718 nickel-based superalloy by inductively coupled plasma atomic emission spectrometry and analysis of rapid evaluation method
The determination uncertainty could intuitively reflect the quality control level of determination process.With the issue and implementation of standards such as GB/T 22553,Top-down method has at-tracted more and more attention.The determination uncertainty of niobium content in IN718 nickel-based superalloy was evaluated and compared based on Top-down method and GUM method.It was found that the uncertainty evaluated by reproducibility standard deviation(sR)in Top-down method was much higher than that in GUM method.The related references about the uncertainty evaluation of metal materials in re-cent years were analyzed.The simplified Top-down method was used.The ratio(U(Rw)/U(w))of the uncertainty evaluated by intermediate precision to the uncertainty evaluated by GUM method was treated by robust statistical method.It was found that the robust mean value was 1.20,and the robust standard deviation was 0.48,indicating that the evaluation results of the two above methods were in good agree-ment.Compared to GUM method,the simplified Top-down method did not require to identify the compo-nents of weighing,certified reference material and repeatability.Moreover,the complicated calculation and combination were not necessary.The evaluation process was simple and easily conducted.The proposed method could help the laboratories evaluate the uncertainty conveniently and rapidly,which could promote the improvement of laboratory quality control level.