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%.

Abstract: A sintered ball having: a chemical composition such that, in percentages by mass based on the mass of the ball: 89%?W?97%; 5%?C?8%; Co?0.5%; Ni?0.5%; Elements other than W, C, Co, and Ni, or “Other elements”: ?3%; a tungsten carbide(s) content greater than 55% in percentage by mass based on the crystallized phases; a bulk density greater than or equal to 14 g/cm3.