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 than the current estimated age of the universe, bismuth-209 has the longest known alpha decay half-life of any naturally occurring element. The very heaviest 24 elements (those beyond plutonium, element 94) undergo radioactive decay with short half-lives and cannot be produced as daughters of longer-lived elements, and thus they do not occur in nature at all. The properties of the chemical elements are often summarized using the periodic table, which powerfully and elegantly organizes the elements by increasing atomic number into rows ("periods") in which the columns ("groups") share recurring ("periodic") physical and chemical properties. The current standard table contains