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Titanium's reducing capability in high temperature is extremely strong. It not only can combine with oxygen, carbon, nitrogen and many other elements, but also can capture oxygen from some of the metal oxides (such as aluminium oxide). Titanium combined with oxygen can form a very thin layer of dense oxide film at room temperature, this layer of oxide film does not react with most of strong acids, strong alkalis, including the King of acids – aqua regia. The corrosion resistance of titanium is reflected in that it only reacts with hydrofluoric acid, hot concentrated hydrochloric acid, concentrated sulfuric acid. According to metal powder supplier, titanium was discovered in 1789. In 1908, Norway and the United States started to produce titanium dioxide by sulfuric acid method, and 1910 was first produced titanium sponge by sodium process in the laboratory, until 1948, United States started to take the method of magnesiothermy to produce tons of titanium sponge. Titanium is often used in the chemical industry because of its corrosion-resistant characteristic. In the past, the chemical reactors which filled with hot nitric parts were made of stainless steel. Stainless steel also cannot resist such strong corrodent - hot nitric acid, every six months, all of those components must be replaced. Now, they are made of titanium, although the cost is more expensive than stainless steel, but it can be continuously used for five years, much more profits. In electrochemistry, the titanium is a one-way valve metal, the potential is negative, usually cannot be decomposed by using titanium as an anode. The biggest drawback of titanium is difficult refining. It mainly because of the strong chemical combination ability of titanium at high temperature, it can be combined with oxygen, carbon, nitrogen and many other elements. Thus, no matter smelting or casting, people are careful to prevent these elements "invasion" titanium. When smelting titanium, the air and water are strictly prohibited close, even the common alumina crucible in metallurgy also prohibit using, because titanium would capture oxygen from alumina. Now, people refined titanium by the reaction of magnesium and titanium tetrachloride in an inert gas - helium, or argon gas. In steel-making, the nitrogen is easy to dissolve in the molten steel, when the steel ingot cooling, the ingot was formed bubbles, affected the quality of steel. So people take the advantage of titanium with strong chemical combination ability at high temperatures, adding titanium powder into molten steel, make it combining with nitrogen to a slag - titanium nitride, floating on the molten steel surface, so that the ingot is relatively pure. When the supersonic aircraft was flying, its wing temperature can reach at 500?. If the wing was manufactured by heat-resistant aluminum alloy, once the temperature reach at 200-300?, the wing also cannot resist, there must be had a kind of light, tough and heat-resistant material to instead of aluminum, and titanium is just to meet these requirements. Titanium also can withstand the test of minus 100 degrees, in such low temperatures, titanium still has good toughness and without brittle. Use of the titanium and zirconium’s strong absorption force to air, it can be removed the air, manufacturing vacuum. For example, vacuum pumps made of titanium can be pumped the air to only one hundred thousandths. Titanium has a "biophile". It can resist the corrosion of secretions and without toxicity in the human body, adapt to any sterilization method. It is widely used in medical devices, for making artificial hip joints, knee joints, shoulder joints, flank joints, skull, active heart valves, bone retaining clip. When new muscle fibre wrapped in these "titanium bones", these titanium bones will begin to maintain the body's normal activities. Article Source:http://www.mhcmp.com
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