Patent Number: 6,167,623

Title: Press roll with a ceramic coating, method for manufacturing the same and coating composition

Abstract: A press roll for a paper or board machine, a method for manufacturing a roll for a paper or board machine and a coating composition for a roll which enable the roll to endure difficult corrosion conditions. An adhesion/corrosion-protection layer having a thickness of from about 150 .mu.m to about 300 .mu.m is applied onto the frame part of the roll by a high-velocity flame spraying technique. The adhesion/corrosion-protection layer contains a nickel-chromium alloy. A tight-ceramic layer having a thickness from about 50 .mu.m to about 150 .mu.m is applied onto the adhesion/corrosion-protection layer by a high-velocity flame spraying technique and includes from about 50% to about 100% of Al.sub.2 O.sub.3 and optionally includes up to about 50% of TiO.sub.2 and/or any amount of Al.sub.2 TiO.sub.5. A porous ceramic layer is applied onto the tight ceramic layer. The tight-ceramic layer may include only Al.sub.2 TiO.sub.5 instead of Al.sub.2 O.sub.3, with or without TiO.sub.2.

Inventors: Niemi; Kari (Tikkakoski, FI), Wahlroos; Juha (Palokka, FI), Lehtonen; Pentti (Jyvaskyla, FI)

Assignee: Valmet Corporation

International Classification: D21F 3/08 (20060101); D21G 1/02 (20060101); D21F 3/02 (20060101); D21G 1/00 (20060101); B23P 015/00 ()

Expiration Date: 01/02/2018