1. Why does aluminium resist corrosion?2. How do we make aluminium stronger?3. Why does titanium resist corrosion?4. What properties make titanium ideal to use in jet engines and nuclear reactors?5. Why do we need electricity to make aluminium and titanium?6. Why does recycling aluminium save electricity?Even if you only know the answer to one question the help will be much appreciated :D
1. When exposed to air, pure aluminium rapidly forms a passive oxide layer, alumina, which further inhibits aluminium reactions with other elements. 2. Aluminium can be made stronger by alloying with other elements. One of the most known aluminum alloy is duraluminium, where the principal alloying component is copper. 3. Exactly as aluminium, titanium corrosion resistance is due to its high reactivity with oxygen. When pure titanium is exposed to air it forms a passive titanium dioxide layer on the surfaces exposed which further prohibits other reactions with corrosion agents. 4. The use of titanium in jet engines components is favored by its strength to weight ration, which is unmatched by any other metal. As for the nuclear reactors, its use is preferred because of its superior corrosion resistance associated with fracture toughness and overall durability. 5. Both titanium and aluminium are refined from their respective mined ores - bauxite, for aluminium, ilmenite and rutile for titanium. Basically, these are oxides of the metals. Pure metal has to be reduced from these ores and processes involve use of temperatures up to and sometime exceeding 1000 degrees Celsius, which obviously requires a great consumption of energy, including electricity. Moreover, pure aluminium is obtained in the final processing phase through electrolysis, meaning an electrical current is needed in order to drive the required chemical reactions, thus adding to the electrical consumption. 6. Recycling aluminium from aluminium simply requires the remelting of the metal, eliminating the electrolytic phase that is high electric energy consuming.
