ChinaAutoRegs｜QC/T 942-2013英文版/English/翻譯/汽車材料中六價鉻的檢測方法
Test Method for Hexavalent Chromium in Automobile Materials
QC/T 941-2013 英文版 汽車材料中汞的檢測方法 Test methods of mercury in automobiles materials
QC/T 942-2013 英文版 汽車材料中六價鉻的檢測方法 Test Method for Hexavalent Chromium in Automobile Materials
QC/T 943-2013 英文版 汽車材料中鉛、鎘的檢測方法 Test Method for Lead and Cadmium in Automobile Materials
QC/T 944-2013 英文版 汽車材料中多溴聯苯（PBBs）和多溴二苯醚（PBDEs）的檢測方法 Test Method for Poly-Brominated Biphenyls (PBBs) and Poly-Brominated Diphenyl Ethers (PBDEs) in Automobile Materials
1 SCOPE
This standard specifies the methods for determining the hexavalent chromium (Cr(VI)) content in automobile parts and materials, where,
"X-ray fluorescence spectrometry" is applicable to screening and rapid determination of Cr(VI) content in automobile materials by using X-ray fluorescence spectrometry.
"Qualitative test for the presence of hexavalent chromium in anti-corrosive metal coatings" is applicable to determining the presence of Cr(VI) in anti-corrosive coatings of automobiles by using spot-test procedure and boiling water extraction procedure. "Determination of hexavalent chromium content in anti-corrosive metal coatings" is applicable to determining the Cr(VI) content in anti-corrosive coatings by using boiling water extraction procedure and colorimetric method. The above two test methods are applicable to the coatings without any additional covering layer, e.g. oil film, water-based or solvent-based polymer film or waxy film.
"Determination of hexavalent chromium content in polymer materials and electronic materials" is applicable to determining the Cr(VI) content in polymers and electronics by using alkaline extraction method and colorimetric method, but not applicable to PE or EVAC material. The Cr(VI) content in other automobile materials, e.g. glass, ceramics, fabrics, and paint coatings, can be determined by reference to this method.
"Determination of hexavalent chromium content in leather materials" is applicable to determining the Cr(VI) content in leather materials by using phosphate solution extraction method and colorimetric method.
2 NORMATIVE REFERENCES
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 1839 Steel product zinc coating mass testing method (GB/T 1839-2008, ISO 1460:1992, MOD)
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 20017 Metallic and Other Non-organic Coatings—Determination of Mass per Unit Area—Review of Gravimetric and Chemical Analysis Methods (GB/T 20017-2005, ISO 10111:2000, IDT)
GB/T 30512-2014 Requirements for Prohibited Substances on Automobiles
GB/Z 21277-2007 Rapid screening of lead, mercury, chromium, cadmium and bromine of regulated substances in electrical and electronic equipment - X-ray fluorescence spectrometry
QB/T 2262-1996 Terms for Leather Industry
QB/T 2706 Leather—Chemical, Physical and Mechanical and Fastness Tests—Sampling Location (QB/T 2706-2005, ISO 2418:2002, MOD)
IEC 62321:2008 Ed.1.0 Electrotechnical products—Determination of levels of six regulated substances (lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls, polybrominated diphenyl ethers)
ISO 3613:2000 Chromate Conversion Coatings on Zinc, Cadmium, Aluminium—Zinc Alloys and Zinc-Aluminium Alloys—Test Methods
EN ISO 17075:2007 Leather—Chemical Tests—Determination of Chromium (VI) Content
3 X 射線螢光光譜法
3. 1 原理
將製備好的樣品置於X 射線螢光光譜儀樣品室內， 按所選定的分析模式對樣品中的銘含量進行X 射線螢光光譜分析，並根據篩選限值判斷樣品中鉻含量是否合格， 以及是否需要進行精確測定。
註： x射線螢光光譜分析所得結果是樣品所含的總路而非六價鉻。
3.2 試劑和材料
3.2.1 棚酸：優級純105 ℃烘1 h 儲存於乾燥器內。
3.2.2 無水囚棚酸鯉：優級純， 700℃灼燒軸，儲存於乾燥器內。
3.2.3 液氮：工業級。
3.2.4 含銘元素的標準物質。
3.3 儀器和設備
3.3.1 X 射線螢光光譜儀。
3.3.2 切割機。
3.3.3 液氮低溫粉碎機。
3.3.4 研磨機：帶碳化鴿（ WC ）磨具。
3.3.5 壓片機：工作壓力不小於20MPa 0
3.3.6 熔樣機：工作溫度不低於1150 ℃ 。
3.4 樣品製備
3. 4. 1 樣品製備原則。
3. 4. 1. 1 用於分析的樣品必須覆蓋光譜儀的測量窗口。
3.4. 1.2 樣品的照射面應能代表樣品整體。
3.4. 1.3 樣品製備過程中應注意防止汙染。
3.4.2 樣品製備方法。
3. 4.2. 1 固體樣品。表面平整、大小適合X 射線螢光光譜儀要求的均質樣品，直接分析。小樣品可匯在一起進行分析。薄樣品，可將其疊在一起達到足夠厚（厚度至少5mm ），需特別注意樣品厚度的一致性及組成的均勻性。分析時為使樣品平整鋪開，可加內襯材料作為支撐物，應儘量選用背景低的內襯材料。
各種塊、板等不定形的樣品以及尺寸過大的樣品，可用切害IJ 機、研磨機等將其加工至合適尺寸。
小樣品（如塑料顆粒等）通過液氮冷凍、機械粉碎再經壓片機壓片製成分析樣品。
玻璃、陶瓷等易碎樣品先粉碎成小塊，再研磨成小於200 目（ 0. 074mm ）的粉末，混勻，用棚酸(3.2.1 ）襯底壓片制樣，厚度不小於1mm ，或用無水四棚酸鯉（ 3.2.2 ）製成玻璃融片分析樣品。
由不均勻材料組成的、無需或難以進－步機械拆分的非均質樣品，將樣品切割破碎，經液氮冷凍，用研磨機將破碎後的樣品研磨成粒徑不超過1mm 的粉末狀樣品，混勻，用棚酸（ 3.2.1 ）襯底壓片制樣，厚度不小於1mm ，或用無水囚棚酸鯉（ 3.2.2 ）製成玻璃融片分析樣品。
3.4.2.2 液體樣品。移取一定體積的液體樣品加入到液體專用樣品杯裡（樣品厚度至少15mm),杯底部用6mm 厚的聚脂膜支撐， 杯上用帶孔的蓋蓋住。