8858cc永利官网(国际)俱乐部 - Limited Company

Among numbers of metal materials, magnesium alloy, as the lightest metal structural material, possesses lots of good performance such as low density, high specific strength and specific stiffness, unique damping and vibration reduction properties, and excellent casting properties. It is widely used in various fields like aerospace, automobiles and electronic products, evaluated as one of the most promising new structural materials at present. However, the further development of the alloy may be affected by the content of impurity elements through influencing its mechanical properties. Therefore, detecting impurity elements in the alloy has become an important part of whether the alloy can be put into use.

So how to detect the presence of impurity elements? ICP-OES is a well-established technique. Complying with U.S. Environmental Protection Agency (EPA) concerning about the main method of environmental laboratory (especially Regulation 200.7 - Determination of Metals and Trace Elements in Water, Solid, and Biosolid Using ICP-AES).

Following we utilized our self-developed ICP-OES to test the content of Al, Cu, Ca, Sn, Pb, Zn, La, Mn, Ni, Ce in the 61-X MGP4 magnesium alloy to judge whether sample has well parallelism and  accuracy , which will be adopted as an analysis method for actual samples.

Reagents and standards

Reagents: high purity nitric acid, superior purity hydrochloric acid, high purity magnesium matrix (≥99.999);

Pure water:18.2MΩ·cm deionized water;

Standard solution: Al, Ca, Ce, Cu, La, Mn, Ni, Pb, Sn, Zn single element standard solution, 1000 ug/mL.

Sample pretreatment

Preparation of analytical test solution: After processing the sample into chips with a thickness of no more than 1 mm, weighed the sample according to Table 3, then added hydrochloric acid and a small amount of nitric acid and heated it on an electric hot plate. After digestion was completed, adjusted the volume to 50 mL, made 3 parallels and 2 blanks respectively

Standard curve and detection limit

Selected the appropriate analysis spectrum line for the element to be measured, and the linear correlation coefficient of the element to be measured was more than 0.999. The detection limit of the method was 3 times the standard deviation of the measured values obtained from 11 consecutive analyzes of the sample blank sample. The detection limit is shown in Table 3.

Precision test

After seven consecutive tests conducted on 61-X MGP4 magnesium alloy, we concluded the precision RSD was less than 3%, which totally can be applied for actual sample analysis.

Actual sample test

According to the above method to test the 61-X MGP4 magnesium alloy sample, combine the measurement data with the national standard "Chemical Analysis Methods for Magnesium and Magnesium Alloys Part 20: Determination of Element Content by ICP-AES" (GB/T13748.20-2009), each difference between the measured value of each element in the sample and the standard value on the certificate meets the reproducibility limit requirements, proving that the data is accurate and reliable.

Conclusion

In this experiment, after digesting magnesium alloy samples by electric heating plate, ICP-OES was employed to measure the contents of Al, Ca, Cu, Mn, Pb, Sn, Zn, Ni, Ce, La, then ensured the method for the subsequent determination of impurity elements in magnesium alloys. Based on the experimental results, the linear correlation coefficients of the established standard curves are all greater than 0.999, the precision of 61-X MGP4 magnesium alloy is less than 3%, the recovery rate of spiking sample is between 93-107%, moreover, the absolute error between the standard values and test value fulfills the requirements of the reproducibility in the national standard; the above series of verification proved that the method is effective and feasible, and this method can be applied to Al, Ca, Cu, Mn, Pb, Sn, Zn, Ni, Ce, La element content testing, and has good stability and accuracy.