Sealing and bearing position repairs Here we have a slideshow with more information about layer modes and sealing surefaces Sealing area on a cylinder head have been restored with a hard copper and a nickel layer as corrosion protection. The surface is finished and a top layer of nickel is added. Sealing faces of gas turbine house plated with copper and then sanded down to the correct tolerance. Corrosions damage where the steam has destroyed the sealing surface and which now is repaired with a hard copper that is 250 Brinell. Now it is plated a dense top layer with nickel so no new corruption will occur.