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US 8,772,190 B2Granted
Large ceramic component and method of manufacture
AssigneeSKF GmbH
InventorsZhijian Shen, Saeid Esmaeilzadeh, Katarina Flodstrom, Charlotte Vieillard
Life of this patent
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Abstract
The invention concerns a sintered ceramic component of silicon nitride or sialon suitable as rolling element in a bearing and a manufacturing method for making such ceramic components. The ceramic component has high density and a homogeneous and fine microstructure, giving the component excellent mechanical properties. Manufacturing of the sintered ceramic component by SPS is cost-effective and rapid.
Claims10
A bearing comprising:
- a rolling element sintered by an electric pulse assisted consolidation (SPS) process, said rolling element comprising silicon nitride, sialon or mixtures thereof and up to 10 weight % of rare earth oxides, aluminium nitride, aluminium oxide and/or oxynitrides of silicon and aluminium as additives, characterized by that the rolling element has a homogeneous microstructure and a density that is at least 99% of the theoretical density, a maximum pore volume of 1 volume %, and a secondary ceramic phase fraction volume not exceeding 0.2 volume %, wherein the secondary ceramic phase comprises unreacted powder or side products formed by sintering the rolling element;
- wherein said rolling element has a diameter of at least 30 millimeters.
A bearing comprising:
- a rolling element sintered by an electric pulse assisted consolidation (SPS) process, said rolling element comprising silicon nitride, sialon or mixtures thereof and up to 10 weight % of rare earth oxides, aluminium nitride, aluminium oxide and/or oxynitrides of silicon and aluminium as additives, characterized by that the rolling element has a homogeneous microstructure and a density that is at least 99% of the theoretical density, a maximum pore volume of 1 volume %, and a secondary ceramic phase fraction volume not exceeding 0.2 volume %, wherein the secondary ceramic phase comprises unreacted powder or side products formed by sintering the rolling element;
- wherein said rolling element has a diameter of at least 30 millimeters, any pores remaining are within 25% or less of the diameter, and any secondary ceramic phase fraction remaining is evenly distributed.
Dependencies are inferred from the claim text.