Product comprising: - a sintered support consisting of an "aggregate" consisting of particles having a size of greater than 100 μm, the balance of said support being the "matrix", and - a protective layer at least partially covering the surface of said support, the aggregate representing more than 60% and less than 95% of the weight of said support and being more than 80% constituted, by weight, of silicon carbide grains, the matrix comprising more than 3% - of crystalline SiAlON phase, or - of a mixture of an iron compound and of crystalline SiAlON phase, the iron compound being able in particular to be chosen from FeO, Fe, Fe t Si, with t between 0.5 and 5.6, Fe 2 SiO 4 , and mixtures thereof, the content of Si 3 N 4 being greater than that of said iron compound, as percentages by weight on the basis of the weight of the matrix, the matrix being more than 90% by weight constituted of: - of SiO 2 and/or - of said iron compound and/or - of SiC and/or - of a crystalline SiAlON phase, in particular Si 3 N 4- α and/or Si 3 N 4- β and/or Si 2 ON 2 , the protective layer being constituted of a glass or of a glass-ceramic, and having the following chemical analysis, as percentages by weight on the basis of the oxides: - 45% ≤ SiO 2 ≤ 90%; - 1% ≤ manganese expressed in the form MnO ≤ 20%, or even MnO ≤ 15%; - 2% ≤ aluminium expressed in the form Al 2 O 3 ≤ 15%; - other elements, apart from oxygen, expressed in an oxide form: ≤ 25%, in which product said crystalline SiAlON phase complies with one of the following formulae: - Si x Al y O u N v , in which: - x is greater than or equal to 0, and less than or equal to 1, - y is greater than or equal to 0, and less than or equal to 1, - u is greater than or equal to 0, and less than or equal to 1, - v is greater than 0, and less than or equal to 1, - x+y > 0, x, y, u and v being stoichiometric indices, normalized relative to the highest index, which is rendered equal to 1; - Me x Si 12-(m+n) Al (m+n) O n N 16-n , with 0 ≤ x ≤ 2, Me being a cation chosen from the cations of lanthanides, Fe, Y, Ca, Li and mixtures thereof, 0 ≤ m ≤ 12, 0 ≤ n ≤ 12 and n+m ≤ 12. - a sintered support consisting of an "aggregate" consisting of particles having a size of greater than 100 μm, the balance of said support being the "matrix", and - a protective layer at least partially covering the surface of said support, - of crystalline SiAlON phase, or - of a mixture of an iron compound and of crystalline SiAlON phase, the iron compound being able in particular to be chosen from FeO, Fe, Fe t Si, with t between 0.5 and 5.6, Fe 2 SiO 4 , and mixtures thereof, the content of Si 3 N 4 being greater than that of said iron compound, - of SiO 2 and/or - of said iron compound and/or - of SiC and/or - of a crystalline SiAlON phase, in particular Si 3 N 4- α and/or Si 3 N 4- β and/or Si 2 ON 2 , - 45% ≤ SiO 2 ≤ 90%; - 1% ≤ manganese expressed in the form MnO ≤ 20%, or even MnO ≤ 15%; - 2% ≤ aluminium expressed in the form Al 2 O 3 ≤ 15%; - other elements, apart from oxygen, expressed in an oxide form: ≤ 25%, - Si x Al y O u N v , in which: - x is greater than or equal to 0, and less than or equal to 1, - y is greater than or equal to 0, and less than or equal to 1, - u is greater than or equal to 0, and less than or equal to 1, - v is greater than 0, and less than or equal to 1, - x+y > 0, - x is greater than or equal to 0, and less than or equal to 1, - y is greater than or equal to 0, and less than or equal to 1, - u is greater than or equal to 0, and less than or equal to 1, - v is greater than 0, and less than or equal to 1, - x+y > 0, - Me x Si 12-(m+n) Al (m+n) O n N 16-n , with 0 ≤ x ≤ 2, Me being a cation chosen from the cations of lanthanides, Fe, Y, Ca, Li and mixtures thereof, 0 ≤ m ≤ 12, 0 ≤ n ≤ 12 and n+m ≤ 12. <EOS>