Synthesis and characterization of noble metal borides: RuBx(x > 1).

Noble metal borides RuB 1.1 , RuB 2 and Ru 2 B 3 have been synthesized by mechanical alloying and high pressure sintering methods using ruthenium (Ru) and boron (B) powders as raw materials. The crystal structures of borides were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results shown that only RuB 1.1 with hexagonal crystal structure was synthesized during the ball milling process, the orthorhombic RuB 2 was synthesized under high pressure (5 GPa) and high temperature (1000 °C) conditions, while the hexagonal Ru 2 B 3 can be synthesized under 5 GPa and 1200 °C. The mechanism of synthesis for the ruthenium borides (RuB x ) are discussed in details. [ABSTRACT FROM AUTHOR]