1,132,291. Coatings. ALUMINIUM CO. OF AMERICA. 17 Jan., 1967 [21 Feb., 1966], No. 2540/67. Heading B2K [Also in Divisions C3 and C7] An aluminium flake product comprises at least 99.9% aluminium the balance being at least one of Ga, Si, Fe, Zn, Cu or Mn in a total amount of 0.001 - 0.1% such that (#G- 0.6)<SP>2</SP> = - 0.5 + 17.41 Ga + 10.30 Si + 36.31 Fe +45.75 Cu +190.4 Zn + 266.3 Mn and is less than 3, where #G is the numerical value of the difference between the diffuse luminous reflectance of a dried film incorporating the aluminium flake product before and after six hours exposure to a 10 volume % solution of HC1. The flake product may have 0.3-3% of a lubricant on the surface thereof and may be prepared by ballmilling the atomized and/or shredded foil in the presence of a lubricant to provide a coated paste pigment. In examples a paint formulation consisting of Aluminium flake pigment paste 2.23% Phthalocyanine blue 0.07% Thermosetting acrylic resin 47.49% Melamine resin 24.83% and Volatile hydrocarbon solvent 25.38% is coated on aluminium panels and force dried at 250‹F for 35 minutes. Lubricants mentioned are stearic, palmitic, myristic, lauric, ricinoleic, behenic, arachidic and oleic acids and trihydrogenated tallow amine.