Magnetic ball
AssigneeSaint-Gobain Centre De Recherches Et D'Etudes Europeen
InventorsDavid BOUTTES, Emmanuel Nonnet
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Abstract
The invention relates to a sintered ball that has the following crystallized phases, in mass percentages based on crystallized phases and for a total of 100%: stabilized zirconia: remainder up to 100%; monoclinic zirconia: ≤20%; 4%≤magnetic component≤22%; crystallized phases other than stabilized zirconia, monoclinic zirconia and magnetic component: <10%; the magnetic component being chosen from among magnetic spinels, magnetic garnets, magnetic hexagonal ferrites and mixtures thereof; the sintered ball comprising, in addition to the magnetic component, CeO2 and optionally Y2O3, in contents that, in molar percentages on the basis of the sum of ZrO2, CeO2 and Y2O3, 3%≤CeO2≤17.5% and 1.5%≤Y2O3+(CeO2)/3.5≤5%.
Claims18
A sintered bead comprising the following crystalline phases, as percentages by weight on the basis of the crystalline phases and for a total of 100%:
- stabilized zirconia:
- complement to 100%;
- monoclinic zirconia:
- ≤20%;
- 4%≤magnetic constituent≤22%;
- crystalline phases other than stabilized zirconia, monoclinic zirconia and magnetic constituent:
- <10%;
- the magnetic constituent being selected from magnetic spinels, magnetic garnets, magnetic hexagonal ferrites and their mixtures;
- excluding the magnetic constituent, the sintered bead comprising CeO2 and optionally Y2O3 in contents such that 3%≤CeO2≤17.5% and 1.5%≤Y2O3+(CeO2)/3.5≤5%, as molar percentages on the basis of the sum of ZrO2, CeO2 and Y2O3.
The sintered bead as claimed in any one of the preceding claims, in which more than 90% of the stabilized zirconia is present in the form of quadratic zirconia, as a percentage by weight on the basis of the stabilized zirconia.
The sintered bead as claimed in claim 9, having a magnetic constituent content of more than or equal to 7% and less than or equal to 15%, as percentages by weight on the basis of the crystalline phases.
Dependencies are inferred from the claim text.