Aluminum has a low density of 2.7g/cm³, and a dense Al₂O₃ film exists on its surface, which prevents the internal aluminum from reacting and is not easily oxidized. It is a commonly used material for aircraft, and 70% of modern aircraft are made of aluminum and aluminum alloys, so it is called the metal that flies.
Why is aluminum trivalent?
Simply put, the outer electron arrangement of the aluminum atom is 2, 8, 3. The number of electrons in the outermost layer is not satisfied, the structure is not stable, 3 electrons are easy to lose, so it is often positively trivalent, but it is obvious that 3 electrons are more stable than the outermost layer of an electron and magnesium and the outermost layer of the two electrons, so the aluminum is not as active as sodium and magnesium.
Why do aluminum profiles generally need surface treatment?
Aluminum profiles without surface treatment, the appearance is not beautiful, and easy to be corroded in the humid air, so it is difficult to meet the requirements of building materials for aluminum profiles of high decorative and strong weather resistance, in order to improve the decorative effect, enhance corrosion resistance and extend the service life of the aluminum profiles generally have to be surface treated.
Why is aluminum more expensive than iron?
Although the reserves of aluminum in the earth's crust is more than iron, but the production process of aluminum is more complex than iron, aluminum is a more active metal element, smelting needs to be through the electrolysis method, in the whole production process to consume the cost is higher than iron, so the price of aluminum is higher than iron.