Metso Paper Inc.

Tampella Telatek Oy

Jorma Majava

Juhani Vestola

Harri Kuosa

Pentti S Lehtonen

Kari Niemi

Juha Wahlroos

Bjarne Hellman

Jussi Tuomela

Jaakko Tenkula

A roll for use in the manufacture of paper and board, a press roll, in particular a center roll in a press, a backup roll for an extended-nip press roll, a hot press roll, or equivalent, which is in direct contact with a wet paper web, or a calender roll, a method for manufacturing the same and a coating composition therefor including an adhesion layer arranged on the frame part of the roll and a ceramic layer arranged on the adhesion layer. The ceramic layer has a thickness of from about 100 &mgr;m to about 2000 &mgr;m and includes from about 50% to about 95% by weight of Cr O and from about 3% to about 50% by weight of TiO , or from about 50% to about 80% by weight of Al O and from about 20% to about 50% by weight of ZrO , or exclusively Al TiO . The outer face of the ceramic layer is finished until the roughness Ra is from about 0.2 &mgr;m to about 2.0 &mgr;m and/or the porosity of the outer face of the roll is from about 1% to about 20%. In addition to or instead of TiO , the ceramic layer may contain oxides of aluminum, silicon, zirconium, magnesium, manganese, tin, tungsten and mixtures thereof.

Method for manufacturing a paper or board machine and coating composition therefor

The invention relates to a Yankee cylinder for a paper-making machine, in which a coating which is a mixture of a metal powder and a carbide or nitride and withstands well the wearing effect of the doctor blade and other corrosive and thermal stresses produced in paper-making is formed on top of the cylinder mantle. The invention also relates to methods for coating a Yankee cylinder with such a coating by using a detonation, plasma or supersonic method.

Yankee cylinder with a plasma-sprayed carbide coating

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Riihimäki, Finland

Jorma Majava