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US 8,771,585 B2Granted
Method for manufacturing ceramic components
AssigneeSKF GmbH
InventorsZhijian Shen, Saeid Esmaeilzadeh, Katarina Flodstrom, Charlotte Vieillard
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AssigneeSKF GmbH
InventorsZhijian Shen, Saeid Esmaeilzadeh, Katarina Flodstrom, Charlotte Vieillard
Estimating the term…
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.
A method for manufacturing ceramic components comprising silicon nitride or sialon or mixtures thereof, with a tailored microstructure by a spark plasma sintering (SPS) procedure in an SPS unit, wherein a powder or pre-formed green body in the SPS unit is treated in a first densification step at a first temperature and a first pressure in order to densify the powder or green body, whereafter the temperature is increased and the pressure is decreased such that the material in the SPS unit is treated in a second grain growth step following the first step at a second temperature which is higher than the first temperature and a second pressure that is lower than the first pressure in order to promote anisotropic grain growth of whisker-like β-silicon nitride and/or β-sialon grains in the component, wherein a holding time of the first densification step is long enough to obtain a density of not less than 97 percent of the theoretical density.
Dependencies are inferred from the claim text.