An anti-corrosion coating to protect against corrosion, comprising: a high-density protective coating on a substrate which is prone to corrosion, preferably metals and/or alloys thereof, containing pre-condensed coat-forming alkoxysilane precursors, wherein the molecules of the pre-condensed coat-forming alkoxysilane precursors are built up from monomer units selected from the group formed by coat-forming alkoxysilane precursors, wherein the molecules of the pre-condensed coat-forming alkoxysilane precursors are cross-linked with each other, wherein the high-density protective coating has a coating thickness of at least 50 μm. The high-density protective coating formed by an inorganic-organic hybrid material, which is preferably produced without solvents (i.e. without the addition of solvents, in particular organic solvents), is comprised of at least one coat-forming alkoxysilane precursor, in particular selected from the group formed by trialkoxysilane precursors.