Sigri Elektrographit Gmbh

Alfred Hirschvogel

Friedrich Wagner

Ernst Freundlinger

Flexible graphite layer material containing at least one metal moylbdate with a solubility in water of 10.sup.-2 to 10.sup.-4 g/100 ml to inhibit corrosion. The corrosion inhibitor may be incorporated by first immersing the graphite layer material in a solution of an alkali metal molybdate, drying, and then immersing in a solution of very soluble metal salt in which the metal when combined with molybdate to form metal molybdate has the defined solubility. The graphite layer material is then dried and contains the desired molybdate corrosion inhibitor.

Flexible graphite sheet, material or layer containing metal molybdate

Production of graphite-hydrogensulfate by dispersing crystalline graphite particles in sulfuric acid, agitating the mixture, adding hydrogen peroxide to the agitated dispersion and continuing agitation until the graphite is converted to graphite-hydrogensulfate. Excess acid is separated and the residual acid in the solid product is removed by washing. The graphite-hydrogensulfate may be heated to transform it into expanded graphite. The method minimizes pollution of the atmosphere with noxious gases and also makes possible ready recovery of unused acid.

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Langweid, Germany

Alfred Hirschvogel