Synthesis of Co-Cr alloy using ultrasonic method

Co-Cr alloys are high temperature resistant and corrosion resistant materials. This research aimed to synthesize Co-Cr alloy powder with ultrasonic method, followed by sintering process in quartz glass capsule. Ultrasonic irradiation was used at 20 kHz frequency and 40 % amplitude with Co : Cr composition ratio of 80 : 20. The treatment time of sonication was for 0, 3, 6, 12, 24, and 48 hours in ethanol solution. After sonication for 48 hours, the FCC phase of Co began to transform into HCP phase. The ultrasonic treatment of the Co-Cr mixture also provided a particle size reduction effect. The parameters of the powder grating after the 48 hours ultrasonication were as follows : for HCP-Co a = b = 0.25074 nm and c = 0.40699 nm, for FCC-Co a = b = c = 0.35411nm, and for BCC-Cr a = b = c = 0.28827 nm. The ultrasonication treatment for 48 hours resulted Co-Cr microalloy of 25.2124 wt%. The result of sintering of Co-Cr solid showed that lattice parameters of HCP-Co were a = b = 0.25230 nm and c = 0.41223 nm, and FCC-Co a = b = c = 0.35232 nm. The formation of Co-Cr microalloying was indicated by EDS results, it was observed that the composition of Co : Cr = 71.25 : 24.45. After sintering process at 1300 ^oC of ultrasonically treatment Co-Cr powders, the Co-Cr alloy portion is increased become of 15.33416 in wt %. (author)