Zirconium is used as an anti-corrosive finishing/surface treatment on metal substrates. If the coating of zirconium is too thin, then the sought-for metal property will not be achieved. Similarly, applying too thick a coat means that treatment material is wasted and so is money. Therefore, ASTM International Committee D01 on Paint and Related Coatings, Materials and Applications has developed a new standard, ASTM D7639, Test Method for Determination of Zirconium Treatment Weight or Thickness on Metal Substrates by X-Ray Fluorescence, to assist in the production of fit-for-purpose and cost-effective parts. According to Christelle Petiot, XRF coatings product manager, Oxford Instruments Analytical, U.K., “This standard will be used to measure the zirconium treatment weight or thickness applied to metal substrates, either along the process line, or in the quality control lab.” In both cases X-ray fluorescence instruments are used; handheld XRF instruments are typically used along the process line for rapid quality control with no sample preparation, and benchtop XRF instruments are used in the quality control lab. The XRF instruments are used to provide qualitative and quantitative data about the metals. ASTM D7639 shows users the performance (precision) that can be achieved by following its simple procedure and using the instrumentation defined in the method. The next step for Committee D01 and its Subcommittee D01.53 on Coil Coated Metal is to develop methods for other treatments such as chromium and titanium. The committee welcomes participation from all interested parties, particularly coil coater professionals.
ASTM Approves Standard for Zirconium Treatment