BORON CARBIDE-TITANIUM DIBORIDE CERAMICS AND REFLECTING MIRROR FOR LASER MACHINING DEVICE AND METHOD FOR MANUFACTURING THE SAME

PROBLEM TO BE SOLVED: To provide boron carbide-titanium diboride ceramics having an electric discharge machinability and a specific rigidity suitable as a material of a reflecting mirror for a laser machining device.SOLUTION: Boron carbide-titanium diboride ceramics is obtained by sintering a mixed power of a boron carbide (BC) powder, a titanium dioxide (TiO) powder, and a carbon (C) powder under a compressed condition and comprises 80 to 73 mol% of boron carbide and 20 to 27 mol% of titanium diboride. The boron nitride powder included in the mixed powder has an average particle size of 1.0 to 2.5 μm and an particle size (D10) of the same corresponding to 10% of weight ratio is 0.3 μm or more, the titanium dioxide powder and the carbon powder has an average particle size of 1 μm or less. Thus, the boron carbide-titanium diboride ceramics having a resistivity of 0.05 cm or less suitable for diesinking electric discharge machining and a specific rigidity of 150 or more necessary as a material for a scan mirror can be obtained.