摘要 |
The invention relates to a powder substantially consisting of boron nitride aggregates. Said powder has an overall chemical composition of 40 to 45 wt.% boron, 53 to 57 wt.% nitrogen, less than 400 ppm calcium, less than 5 wt.% other elements in total, and more than 90 wt.% boron nitride, limits included, and, in weight percent and on the basis of all the crystallized phases, mean circularity greater than or equal to 0.90, a median pore size less than or equal to 0.5 µm, and open porosity less than or equal to 55%. |