Abstract: Method for detecting at least one critical defect in a ceramic rolling element providing the steps of capturing a plurality of two-dimensional digital radiographic images of the ceramic rolling element; digitally filtering each radiographic image; delineating, on the basis of the filtered image, at least one region liable to comprise the critical defect; constructing stereoscopically a virtual model of the ceramic rolling element having the region; comparing the dimensions of the delineated region with a plurality of predetermined threshold values, and, when the dimensions are greater than the threshold values, generating an alarm signal.

Abstract: Method for detecting at least one critical defect in a ceramic rolling element providing the steps of capturing a plurality of two-dimensional digital radiographic images of the rolling element; digitally filtering each radiographic image; delineating, on the basis of the filtered image, at least one region liable to comprise the critical defect; constructing stereoscopically a virtual model of the rolling element having the region; comparing the dimensions of the delineated region with a plurality of predetermined threshold values, and, when the dimensions are greater than the threshold values, generating an alarm signal.

Abstract: A Hybrid rolling bearing includes an inner raceway and an outer raceway and a plurality of rolling elements arranged therebetween. The outer raceway and the inner raceway are made from bearing steel, having a first surface RMS roughness Rq1. The rolling elements are made from a ceramic material and have second surface RMS roughnesses Rq2,i. At least one of the rolling elements has an increased surface RMS roughness Rq2,N, which is significantly higher than the RMS roughnesses Rq2,i, of the remaining rolling elements. The hybrid rolling bearing can be installed within a refrigerant compressor.

Abstract: A Hybrid rolling bearing includes an inner raceway and an outer raceway and a plurality of rolling elements arranged therebetween. The outer raceway and the inner raceway are made from bearing steel, having a first surface RMS roughness Rq1. The rolling elements are made from a ceramic material and have second surface RMS roughnesses Rq2,i. At least one of the rolling elements has an increased surface RMS roughness Rq2,N, which is significantly higher than the RMS roughnesses Rq2,i, of the remaining rolling elements. The hybrid rolling bearing can be installed within a refrigerant compressor.

Abstract: A bearing includes a liquid lubricant and at least one ceramic component, which, during operation of the bearing, is subject to rolling contact load. A tribological surface of the at least one ceramic component is impregnated with a sealant, such that the liquid lubricant is prevented from entering discontinuities in the tribological surface.

Abstract: The present invention provides a ceramic material comprising: a first phase comprising zirconia, yttrium and cerium, wherein the yttrium and cerium are present in a molar ratio of 0.15 to 0.5 and in a combined amount of 5 to 15 mol %, a second phase comprising alumina, and a third phase comprising metal aluminate platelets.

Abstract: The invention concerns a method for manufacturing a ceramic material with pseudo-isotropic microstructure. The method for tailoring the microstructure for manufacturing of sintered ceramic components involves a spark plasma sintering (SPS) process. By performing the SPS process in at least two steps it is possible to separate densification from grain growth. An initial sintering step at a first temperature and a first pressure, followed by a controlled grain growth step at a higher temperature and lower pressure makes it possible to manufacture ceramic components with controlled microstructure and improved mechanical properties.

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.

Abstract: The present invention relates a bearing comprising a liquid lubricant and at least one ceramic component (105, 115, 125), which, during operation of the bearing, is subject to rolling contact load. According to the invention, a tribological surface (110, 120, 130) of the at least one ceramic component is impregnated with a sealant, such that the liquid lubricant is prevented from entering discontinuities in the tribological surface.

Abstract: The present invention provides a ceramic material comprising: a first phase comprising zirconia, yttrium and cerium, wherein the yttrium and cerium are present in a molar ratio of 0.15 to 0.5 and in a combined amount of 5 to 15 mol %, a second phase comprising alumina, and a third phase comprising metal aluminate platelets.

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.

Abstract: The invention concerns a method for manufacturing a ceramic material with pseudo-isotropic microstructure. The method for tailoring the microstructure for manufacturing of sintered ceramic components involves a spark plasma sintering (SPS) process. By performing the SPS process in at least two steps it is possible to separate densification from grain growth. An initial sintering step at a first temperature and a first pressure, followed by a controlled grain growth step at a higher temperature and lower pressure makes it possible to manufacture ceramic components with controlled microstructure and improved mechanical properties.

Abstract: A bearing includes an inner bearing ring on which a raceway is formed. The ring includes at least a first component of light metal material and at least a second component of fully dense ceramic material, where the first component and the second component are separate entities joined together, and where the second component forms at least part of the raceway. The first component includes two lightweight metal parts interconnected by a screw thread which can be tightened to induce compressive pre-stress in the second component to compensate for low tensile strength of the ceramic material.

Abstract: A bearing comprises at least one bearing ring on which a raceway is formed. The ring comprises at least a first component of light metal material and at least a second component of fully dense ceramic material, where the first component and the second component are separate entities joined together, and where the second component comprises at least part of the raceway.

Abstract: An improved rolling bearing, in particular one being used in aqueous environment, such as water and steam, comprising an outer race, an inner race, rolling elements, and a retainer holding said rolling elements in a spaced relation from each other, wherein the races of the bearing are made of stellite, the rolling elements are made of hot-isostatic-pressed alumina-zirconia composites, and the retainer is made of poly-ether ether ketone comprising graphite fibers, graphite powder, and polytetrafluoroethylene.

Abstract: The present invention relates to an improved rolling bearing, in particular one being used in aqueous environment, such as water and steam, comprising an outer race, an inner race, rolling elements, and a retainer holding said rolling elements in a spaced relation from each other, wherein the races of the bearing are made of stellite, the rolling elements are made of hot-isostatic-pressed alumina-zirconia composites, and the retainer is made of poly-ether ether ketone comprising graphite fibers, graphite powder, and polytetrafluoroethylene.