BEARER FOR THE SCREEN OR FELT OF A PAPER OR CARDBOARD MACHINE, PROCESS FOR MAKING IT AND ITS USE

摘要

A bearer for the screen or felt of a paper machine consists of one or more combined sintered mouldings based on silicon nitride, the main structural phase of which is needle-like beta silicon nitride grains which are surrounded by an amorphous or partly crystalline grain boundary phase of a rare earth/aluminium silicate phase, in which the cationic impurity content of the sintered moulding is less than 1 wt % and all parts by weight are made up to 100 wt % and said grains have an average diameter of no more than 1.5 mu m. The sintered mouldings have a bend strength of at least 500 MPa and a Vickers hardness HV 0.5 of 1,400 to 1,700.