Cobalt-chrome turbines, and many others. The common Co-Cr alloy production requires the extraction of cobalt and chromium from cobalt oxide and chromium oxide ores. Both of the ores need to go through reduction process to obtain pure metals. Chromium usually goes through aluminothermic reduction technique, and pure cobalt can be achieved through many different ways depending on the characteristics of the specific ore. Pure metals are then fused together under vacuum either by electric arc or by induction melting. Due to the chemical reactivity of metals at high temperature, the process requires vacuum conditions or inert atmosphere to prevent oxygen uptake
Chemical element so long (at least 100 million times longer than the estimated age of the universe) that their radioactive decay has yet to be detected by experiment. Elements with atomic numbers 83 through 94 are unstable to the point that their radioactive decay can be detected. Three of these elements, bismuth (element 83), thorium (element 90), and uranium (element 92) have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced the heavy elements before the formation of our solar system. For example, at over 1.9 years, over a billion times longer