GB/T 31854-2015Test method for measuring metallic impurities content in silicon materials used for photovoltaic applications by inductively coupled plasma mass spectrometry (English PDF)

1 Scope

This standard specifies a method for the determination of trace metal impurities in silicon materials for photovoltaic applications by inductively coupled plasma mass spectrometry (ICP-MS).

This standard applies to the determination of trace metal impurities of iron, chromium, nickel, copper, zinc in silicon materials for photovoltaic applications.

The measurement range of each element is as shown in Table 1.

2 Normative references

The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this standard.

d) Standard storage solution: The concentrations of iron, chromium, nickel, copper, zinc, yttrium are all 1 mg/mL; certified reference materials that can be traced to the source at home and abroad are used;

e) Nitric acid solution: The volume ratio of nitric acid and ultrapure water is VHNO3:VH2O = 1:19;

f) Nitric acid-hydrofluoric acid mixed solution: The volume ratio of nitric acid and hydrofluoric acid is VHNO3:VHF = 1:2.

6 Apparatus and equipment

This method requires the following instruments and equipment:

a) Inductively coupled plasma mass spectrometer;

b) Analytical balance: The sensitivity is 0.1 mg;

c) Fume hood;

d) Utensils: The utensils used shall be made of polytetrafluoroethylene (PTFE) or perfluoroalkoxy resin (PFA) and other materials that are resistant to hydrofluoric acid corrosion and can be cleaned;

e) Electric heating plate.

7 Environmental conditions

7.2 Relative humidity: It shall not be greater than 65%.

7.3 Cleanliness: It shall be better than the ISO level-6 cleanliness requirements as defined in GB/T 25915.1-2010.

8 Specimen preparation

8.1 Process the sample into particles that are easy to dissolve; it shall strictly avoid contamination during the crushing process.

8.2 Treat the specimen in an appropriate concentration of hydrofluoric acid solution; add an appropriate concentration of nitric acid solution if necessary; use ultrapure water to wash it.

8.3 Dry the specimen at 100 °C ~ 110 °C to prepare for use.

9 Test procedure