ISO 17925:2004 specifies methods of determining the coating mass per unit area by gravimetry and chemical composition on one side-surface of zinc- and/or aluminium-based coatings on steel by means of inductively coupled plasma atomic emission spectrometric or flame atomic absorption spectrometry.This method is applicable to zinc contents between 40 % (mass fraction) and 100 % (mass fraction); aluminium contents between 0,02 % (mass fraction) and 60 % (mass fraction); nickel contents between 7 % (mass fraction) and 20 % (mass fraction); iron contents between 0,2 % (mass fraction) and 20 % (mass fraction); silicon contents between 0,2 % (mass fraction) and 10 % (mass fraction); lead contents between 0,005 % (mass fraction) and 2 % (mass fraction).These test methods are intended as referee methods to test such materials for compliance with mass per unit area and compositional specifications of International Standards.