| 摘要 |
<p>A supporting member, for example, the screen table supporting table, foil, suction box cover or tubular suction apparatus, for positioning in engagement with the screen or felt of a paper or cardboard machine, which supporting member is capable of supporting, or assisting in the supporting of a screen, for drainage and for sheet forming, and which has a part or parts as a wear element or elements that are in contact with the screen or felt and consist of one or more ceramics components of hard, dense sintered aluminium oxide having an Al2O3 content of at least 95% by weight, the or each ceramics component having the following features: (1) a content of Al2O3 of from 97% to 98.5% by weight, a content of MgO of 0.5 + 0.3% by weight, and a content of SiO2 of from 1% to 2.5% by weight; a total of not more than 0.2 weight % impurities being present (2) a Synder-Graff grain size of 5/.mu.m + 2.mu.m; (3) a Vickers hardness of more than 1600 daN/mm2 at a testing load of 0.2 daN/mm2; (4) a bending strength of at least 300 N/mm2; (5) a transcrystalline fracture proportion of more than 70%; and (6) a surface characteristic specified by (a) a roughness of Ra < 0.2.mu.m, measured with a feeler needle having a radius of 3.mu.m on a polished surface, (b) a proportion of pores in the surface of less than 10%, and (c) a mean (median) pore size < 5.mu.m.</p> |
