This part of GB/T20975 specifies the extraction and separation-diphenylcarbazide spectrophotometry, flame atomic absorption spectrometry, ammonium persulfate oxidation-ferrous ammonium sulfate titration method for the determination of chromium content in aluminum and aluminum alloys, water immersion Determination of hexavalent chromium content in aluminum and aluminum alloys using diphenylcarbazide spectrophotometry. This section applies to the arbitration determination of chromium content in aluminum and aluminum alloys and hexavalent chromium content in aluminum and aluminum alloys. Determination of chromium by extraction and separationdiphenylcarbazide spectrophotometry: 0.0001% to 0.60%; Determination of chromium by flame atomic absorption spectrometry: 0.010% to 0.60%; ammonium persulfate oxidationferrous ammonium sulfate titration The determination range of chromium by water leaching method is: 2.00% ~ 23.00%; the determination range of hexavalent chromium by water leaching diphenylcarbazide spectrophotometry: 0.0001% ~ 0.10%. Note: When the chromium mass fraction is 0.010% to 0.60%, the extraction separation-diphenylcarbazide spectrophotometry method is used as the arbitration method.
GB/T 20975.18-2020 Referenced Document
GB/T 8005.2 Terms of aluminium and aluminium alloys—Part 2:Chemical analysis
GB/T 8170-2008 Rules of rounding off for numerical values & expression and judgement of limiting values
GB/T 20975.18-2020 history
2020GB/T 20975.18-2020 Methods for chemical analysis of aluminium and aluminium alloys—Part 18:Determination of chromium content
2008GB/T 20975.18-2008 Methods for chemical analysis of aluminium and aluminium alloys.Part 18: Determination of chromium content
2001GB/T 6987.18-2001 Aluminium and aluminium alloys--Determination of chromium content--Flame atomic absorption spectrometric method