Since the end of 2013, NOF Metal Coatings Group’s Geomet 321 has been used by Siemens Wind Power A/S on fasteners of wind turbine blades. For this application, Siemens requires that the coating must be able to exist in a C5-H environment (according to ISO-12944) without corrosion of the substrate material even after a 1440hr salt spray test. For this reason, Geomet 321 is being applied with a thickness of 15µm.
At the same time, GE Power & Water (General Electric division in charge of the construction of wind power plants) has approved the zinc flake systems Geomet and Geoblack in its latest standard P14A-AL-0218. Specific requirements such as 1000hr salt spray resistance (according to ASTM-B117 or ISO-9227) could be met and mechanical damage tests were convincing.
In addition to these new standards, the systems Geomet 321 + Plus VLh on the one hand and Geomet 500 + Plus XL on the other, have been certified by the institute Germanischer Lloyd regarding the corrosion protection of fasteners in oceanic and offshore atmosphere with high salinity levels (C5-M high according to ISO-12944). This means a salt spray resistance of 1440 up to 2016hr without appearance of red rust.
