| abstract |
A high-strength machinable ceramic capable of high-precision fine machining has a coefficient of thermal expansion close to that of silicon and preferably a uniform blackish color which facilitates image processing of machined parts. The ceramic comprises a main constituent and a sintering aid. The main constituent comprises 30-59.95 mass % of boron nitride, 40-69.95 mass % of zirconia, optionally up to 20 mass % of silicon nitride and 0.05-2.5 mass % (calculated as an element) of at least one coloring additive, which is selected from C, Si, elements of Groups IIIA-IVB in the fourth period, elements of Groups IVA-VB in the fifth period, elements of Groups IVA-VIB in the sixth period of the long form periodic table, and compounds of these elements. |