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Sergey Venezky
STORIES ON METALS

TITANIUM

SON OF THE EARTH

Rocket freezes in the sky. - "Change if you last name?" - In honor of the sons of Gaia. - A Herculean task. - Mistake after mistake. - Wide response. - A fly in the ointment. - The irony here is inappropriate. - Liberation from captivity. - "Black bird". - Here is the excerpt! - Rowers change boats. - A paradox? - On the papyrus boat RA. - Ridiculous point of view. - A thousand years later. - In the oceanic abysses. - The third spire of St. Petersburg. - The Acropolis is closed for renovation. - Defect is curable. - So rare! - A little fiction. - Mine in the Sea of Tranquility. - In the arms of oxygen. - Heavy testing.

August 18, 1964 in the pre-dawn hours on Prospekt Mira in Moscow launched a space rocket. This star ship was not destined to reach the moon or Venus, but the fate prepared for him, no less honorable: forever frozen in the Moscow sky, silver obelisk must carry through the centuries the memory of the first path laid by the Soviet man in space.

The authors of the project could not choose a facing material for this Grand monument. First, the obelisk was designed in glass, then in plastic, then in stainless steel. But all of these options were rejected by the authors. After much thought and experimentation, it was decided to stop on the polished titanium sheets.

Why on Titan was given such an honorable mission - to tell their descendants about the heroism of our contemporaries?

Titanium is called an everlasting material. But before talking about the properties, get acquainted with the biography of this metal.

If the Titan had to fill out a questionnaire in the column "Change if You last name?" he would have had to specify that until 1795 was called "menaquinol". This name was given to this element opened it in 1791, English clergyman William Gregor, in his spare time enthusiastically engaged in Mineralogy and chemistry. Near his parish in the town of Manakan in Cornwall, he found something in an unknown mineral in the form of dark coarse sand. In it was found a previously unknown element. Gregor dubbed the mineral menakanit, and the new element menaquinol.

But, apparently, this name had the item is not to your taste and at the first opportunity (as it had in 1795, when the German chemist Martin works again opened the item - this time in the mineral rutile), he changed it to beautiful, to much binding the name "Titan". The titans in Greek mythology was the name of the sons of Gaia - goddess of the Earth.

Two years later it turned out that Gregor and works opened one and the same element, which since then has established a proud name - titanium.

To open an item - it does not mean to isolate it in pure form. And Gregor, and Works only managed to obtain the chemical compound of titanium with oxygen - white crystalline powder of titanium oxide. The selection of titanium from its compounds turned out to be a truly Herculean task. To solve it, tried many famous chemists of the last century, but all of them would fail.

At one time it seemed that the search of English academic Wollaston were unsuccessful. Exploring in 1823 crystals found in metallurgical slags, he came to the conclusion that the crystalline substance is nothing other than pure titanium. After 33 years, a German chemist wöhler discovered that these crystals are a combination of titanium with nitrogen and carbon, and does not free the Titan, as erroneously believed Wollaston.

For many years believed that the first metallic titanium was obtained in 1825, the famous Swedish scientist Berzelius when restoring formetanate potassium metal sodium. But today, comparing the properties of titanium and the product obtained by Berzelius, it can be argued that the essential Secretary of the Royal Swedish Academy of Sciences was wrong, for pure titanium is quickly dissolved in the hydrofluoric acid (unlike many other acids), and titanium of Berzelius successfully resisted its action.

Only in 1875 by the Russian scientist D.K. Kirillov managed to get the metal titanium. The results of these works D.K. Kirillov published in the brochure "Research on Titan". But in the conditions of tsarist Russia, this important work nobody was interested and so went unnoticed.

In 1887 a fairly pure product is about 95 % titanium - received compatriots of Berzelius Nilson and Peterson, restored the titanium tetrachloride with metallic sodium in a steel pressure bomb.

The next step on the path to pure titanium made in 1895 a French chemist Moissan, who restored the titanium oxide with carbon in an arc furnace and then subjected the resulting metal double refining. Its titanium contained only 2% of impurities.

Finally, in 1910, American chemist hunter, improving the method of Nilsson and Peterson, managed to get a few grams of relatively pure titanium. This event caused a wide resonance in different countries. That is why many people still mistakenly attributed to hunter, not his predecessors priority allocation of titanium in its pure form.

So, pure titanium was obtained. But clean it could be considered a stretch, as it still contained a few tenths of a percent impurities. Just a few tenths... But a fly in the ointment spoil a barrel of honey. Impurities did Titan fragile, fragile, not machinable. On it went notoriety as useless metal, not suitable for any purpose. Of course, with that titanium could not even dream about responsible work. Had to settle for minor roles.

In 1908, rose and Bertran in the United States, and Farup in Norway has offered to produce white not of compounds of lead or zinc, as was done before, and titanium oxide. Such whitewash can be painted several times greater surface area than the same amount of lead or zinc white. Besides titanium oxide is not toxic (beach of white lead), since the titanium oxide is harmless to the human body. Medicine known case when a citizen "took" at one time almost a pound of this substance without any unfortunate consequences.

Over time, the titanium oxide was applied in the dyeing of leather, fabrics, glass, porcelain, enamel, for the manufacture of artificial diamonds.

There was work for other titanium compounds already mentioned of titanium tetrachloride, first obtained by the French chemist Dumas back in 1826. The ability of this compound intensively to form a masking smoke curtains were widely used during the first world war. In the peaceful years it is used for fumigation of plants during spring frosts.

But Titan, as we will see later, had the right to claim to be more serious and interesting work.

And finally, in 1925, the Dutch scientists van Arkel and de Boer decomposition of titanium tetrachloride on a hot tungsten wire got titanium very high purity. Then it turned out that the popular view about the fragility of the titanium does not hold water, as the metal is obtained by van Arkel and de Boer, had a very high plasticity: it was possible to forge in the cold as iron, laminating the sheets, tape, wire and even the thinnest foil.

Now the proud name that wore the item, nobody seemed, as before, by the irony of fate before him opened wide road in the world of technology.

As if in gratitude for deliverance from the captivity of impurities Titan began to amaze scientists for its miraculous properties. It was found, for example, that titanium, which is almost twice lighter than iron, was stronger than many steels. On the specific strength of titanium has no rivals among the industrial metals. Even such a metal as aluminum, lost a number of positions to the titanium, which is just one and a half times heavier than aluminum, but six times stronger. And most importantly, titanium retains its strength at high temperatures (up to 500°C, and with the addition of alloying elements up to 650°C), while the strength of most aluminum alloys sharply decreases already at 300°C.

Titanium is a very hard metal: it is much harder than aluminum, copper and even iron. The higher the yield strength of the metal, the more confident the details from him resist operational loads, the longer they retain their shapes and sizes. The yield strength of titanium five times higher than that of aluminum, and almost three times higher than that of iron.

It is not surprising that when the front of the aircraft, the question arose, what metal to trust the sound barrier, the choice fell on Titan. In the 60-ies in the foreign press reported the establishment of the United States supersonic jet "Black bird", which can reach speeds of more than 3,200 kilometers per hour. The body of this machine was made of titanium. Since the position of titanium in aircraft strengthened: its alloys produce the outer parts of the aircraft (engine nacelle, ailerons, rudders turn) and many other components and parts from the engine to the nuts and bolts. Thanks to Titan aircraft become easier, and thus, increases their capacity. Thus, only the replacement of steel bolts of the engine titanium in one type of fighter the weight of the engine is reduced almost one hundred pounds. According to experts, in the coming years the share structures of titanium and its alloys in the aircraft, the speed of which is two to three times higher than the speed of sound will increase by 60-90%.

Without this metal and space technology. Excellent performance is demonstrated, in particular, titanium tanks for storage of liquid oxygen and hydrogen: at very low temperatures, the titanium is not destroyed, like most metals, but becomes even stronger. Apparently, titanium is the main structural material objects, mounted directly in space. As shown by experiments conducted in 1969, the Soviet cosmonauts Georgi Sonnym and Valery Kubasov, the metal in the conditions of space vacuum is easy welding and cutting.

With respect to the titanium constructors are not only heavenly equipment. Engineers of the GDR, for example, used a hardening a titanium coating for parts of watches: a thin layer of titanium - 0.2 micron - several times increases the durability of the watch mechanism, increases the precision. For photographers, specializing in shooting sports events, in Japan created the camera, allowing you to take pictures with the shutter speed at 1/4000 of a second: this has become possible due to titanium alloy, which is made of the focal plane shutter camera. Bike frame titanium weighs little more than a kilogram, and the whole bike in less than 7 pounds. These lightweight machines are in great demand among athletes. Rowers top of the line too willingly replaced the old boats-Scythians new from carbon fiber and titanium alloys: the "eight" easier still for a good 20 pounds.

Titanium has attracted the attention of chemists. One of the plants was carried out the following experiment. Cast iron, stainless steel and titanium have produced three pump for pumping corrosive liquids. The first was "eaten" after three days, the second lasted ten days, and the third (titanium) and after six months of continuous operation was unhurt.

Despite the fact that titanium is more expensive, replacing them with less expensive materials in many cases is economically advantageous. Thus, the reactor vessel of a chemical apparatus, made of titanium alloy, is four times more expensive than the same stainless steel. But steel reactor is only six months, and titanium ten years. Add the cost of frequent replacement of steel reactors, Yes loss caused by downtime, and it becomes obvious that expensive titanium, ironically, cheaper than cheap steel.

The exhibition on the use of titanium in industry, organized a few years ago in London, showcasing a wide range of equipment for chemical plants, made of titanium. Titanium nozzle, after more than two months in the atmosphere of hot gases containing sulfur dioxide, could as if nothing had happened to continue working on; nozzle stainless steel was destroyed after a few hours of work. Successfully use titanium for the production of parts, working in an atmosphere of vapors of chlorine, sulfuric or nitric acid and other chemical "aggressors". Some enterprises have got even a huge, a height of 120 meters, ventilation pipes made of this metal. Of course, this pipe is expensive, but it will last without repair good hundred years - all costs will be repaid with interest.

The most widely used titanium in the production of hard alloys for cutting tools. A thin coating of titanium carbide greatly improves the cutting properties of the tool, improves the surface quality of the processed products.

The good reputation enjoyed excellent surgical instruments made of titanium alloys. The Soviet doctor Yuri Senkevich party international expedition led by the famous Norwegian Explorer Thor Heyerdahl - took with him on a long voyage on the papyrus boat RA titanium surgical instruments - lightweight, corrosion resistant, durable.

In the 60 years, scientists have created an amazing alloy of Nickel titanium, nitinol, which has the unusual property to "remember" their past, and more specifically, to take after deformation and related processing its previous form (details are explained in the essay "the bronze devil", devoted to Nickel).

At the beginning of this century among metallurgists believed that the titanium - harmful admixture of iron. It took many years to prove the absurdity of this view. Today metallurgy is one of the main consumers of titanium. We have hundreds of steels and alloys, which in one way or another number includes this element. In stainless steel it is introduced to prevent intergranular corrosion. In the heat-resistant high-chromium alloys, it reduces the size of the grain, making the metal structure is homogeneous and crystalline. In other heat-resistant alloys titanium serves as a reinforcing element.

The high affinity of titanium for oxygen (to this we shall return) can be used for deoxidation of steel, i.e. to remove oxygen: rascalities ability of titanium is approximately 10 times greater than silicon is one of the principal deoxidizers. Is the role of titanium and nitrogen. Cleaning of steel from gas increases its mechanical properties, improves corrosion resistance.

One of the remarkable properties of titanium and its unusual resistance to corrosion - this evil enemy of metals. The record titanium 10 years in sea water is not displayed and a trace of rust (for such period from the iron plate would remain only memories). Yes there some ten years: the calculations show that if this experiment began a thousand years ago, for example, when passed the baptism of Russia, to our time corrosion could penetrate deep into the Titan just by 0.02 mm. No wonder, therefore, that the shipbuilders, the hydraulic engineer, designers, deep-diving vehicles are to titanium no less sympathy than the aircraft designers and chemists. The American company "General electric" was intended to create a project manned stations that can be accommodated at depths of up to 3700 meters. Titanium alloys in this project will have an important role.

High corrosion resistance of titanium - here is an explanation of why the creators of the obelisk, commemorating the conquest of space, chose this metal as a facing material. About the same period, the Titan, it was decided to use even for a single monumental buildings. In the competition of projects of monuments in honor of the 100 anniversary of the organization of the International telecommunication Union, organized by UNESCO, the first prize (out of 213 submitted projects has been the work of Soviet architects. The monument, which was supposed to be set at the place des Nations in Geneva, was to represent two concrete shell height of 10.5 meters, lined with plates of polished titanium. Man that runs between the two shells at a special track, could hear their voices, footsteps, the noise of the city, to see his image in the center of the circles, stretching out into infinity. This project is not yet implemented, but other Soviet obelisk, also made of titanium, already adorns the Park of the Palais des Nations in Geneva: 28-metre-high monument, which symbolizes the human desire to penetrate into outer space and the successes achieved in this way, in 1971, transferred to the Soviet Union in the gift of the United Nations.

In 1980, in Moscow, a monument to Yuri Gagarin: a twelve figure of the first cosmonaut of the planet on a tall column-pedestal and model of the spacecraft "Vostok", which was made the historic flight, made of titanium. And in the panorama of Leningrad, is unthinkable without the two famous towers and spires of the Admiralty and the Peter and Paul fortress, perfectly blended with another spire crowning the building of the country's largest Naval station, built on Vasilievsky island. Material for this spire adorning the sea port of St. Petersburg, was still the same titanium, which became a popular material for architects, sculptors, and builders.

If Titan was known to the ancient Greeks, it is quite likely that they would use it as a building material in the construction of buildings of the Athenian Acropolis. But, unfortunately, the architects of antiquity did not have '*eternal metal". Their wonderful creations has been exposed to the destructive influence of centuries. Time ruthlessly destroyed the monuments of Hellenic culture. In the beginning of our century visibly aged Athenian Acropolis had to be repaired: the individual elements of buildings bonded steel reinforcement. But the years passed, the metal in some places eat rust, many marble slabs have settled and cracked. To suspend the destruction of the Acropolis, it was decided to replace steel fasteners titanium, which corrosion is not terrible.

An important characteristic of titanium is its reminicent: even in a strong magnetic field can not render any influence. In some cases this antimagnetic "immunity" is very useful. Thus, the participants of the Arctic expedition of the newspaper "Soviet Russia", emerging in 1983, dog sledding more than ten thousand kilometers along the coast of the Arctic ocean, was carried on a non-magnetic titanium sleds unique device magnetometer in Northern performance.

So, titanium is the happy owner of many valuable qualities. Not accidentally remarkable Soviet Metallurgist academician I.P. Bardin fought for the full development of the metallurgy of titanium in our country. "Metal today, " wrote the scientist, is not only the iron and steel..., this titanium - young rival iron, exceeding all the traits of his "character" and lightness, and strength, and heat resistance, and corrosion resistance". Why still it is used in industry is not as widely used as, for example, steel or aluminum?

High price - that to some extent inhibited the consumption of titanium. In fact, this "defect" is not innate, but only due to the extreme difficulty of extracting titanium from ores. If we take the relative price of titanium concentrate per unit, after a long and difficult process path, which overcomes the titanium in the process of transformation into finished products - thin sheet, the cost increases hundreds of times. But it is reparable trouble: the production of new metal is continuously improved, and not far off the time when he will be as cheap as aluminum, which at the end of last century competed with precious metals. The stores can already be found Cutlery, kitchen utensils made of titanium and its alloys - titanium "moving the masses".

'Rare' TitanUntil very recently, titanium inappropriately attributed (and sometimes are) rare metals. In reality, very few elements are common in nature more than titanium. The amount of titanium in the earth's crust is several times the reserves of metals such as copper, zinc, lead, gold, silver, platinum, chromium, tungsten, mercury, molybdenum, bismuth, antimony, Nickel, tin, put together. That's so rare!

However, in a certain sense, the term "rare" has something to do with titanium: it is rare rock does not contain a particular quantity of this element. There are about 70 of titanium minerals in which it is in the form of oxides or salts of Titanic acid. Greatest practical importance are ilmenite (previously named menakanit), rutile, peroxid and sphene. "Company" titanium minerals is constantly expanding. In the Lovozero tundra, Kola Peninsula, geologists have found a previously unknown stone (or rather, grit - because finding weighed only a tenth of a gram), which was named notesitem as its main components were sodium, titanium and silicon (silicium). A tiny crystal of another new titanium containing mineral, the size of one square millimeter, found in the Northern Baikal region. In honor of the outstanding Soviet physicist, academician L.D. Landau this rare mineral was named landowner.

Just on the globe there are more than 150 significant ore and placer deposits of titanium. But no matter how rich earth minerals, sooner or later underground storage is empty. That is why in search of metallurgical raw materials the eyes of scientists and science fiction writers are increasingly turning to the ocean depths and outer space. One of the main characters in a science fiction novel by the famous Soviet paleontologist and writer I.A. Efremov "Andromeda" Gift of the Wind working on the underwater titanium mine, located near the coast of South America. Here is the picture appears before the eyes of the hero, who arrived there to begin: "Far out at sea were given artificial stranded ending washed wave strikes the tower. She stood at the edge of the continental slope, steeply falling into the ocean at a depth of one kilometer. Under the tower went down steeply huge mine in the form of Tolstaya cement pipes, withstand the pressure of deep water. At the bottom of the pipe rested on the summit of a submarine mountain, consisted almost entirely of pure rutile titanium dioxide. The processing of the ore produced at the bottom, under the water and mountains. On the surface rose by only large ingots of pure titanium and the dregs of mineral waste, spread far around."

Before flying the American spacecraft Apollo and Soviet automatic station "Luna", brought to Earth samples of lunar rocks, some scientists have suggested that lunar soil contains a relatively large amount of titanium. Now yesterday's hypothesis has been experimentally confirmed fact. Who knows, maybe in the near future Newspapers will report that somewhere in the region of the Sea of Tranquility or Ocean Storms began to act first on the moon titanium mine.

Interesting data were delivered to the Earth by the Soviet cosmonauts Pyotr Klimuk and Valentin Lebedev - the crew of the spaceship "Soyuz-13". They managed to get the UV spectrogram of one of the planetary nebulae, astronomers have always shown a keen interest. Typical nebula is a gas formation of a hot star in the center. Because these celestial objects are at a huge distance from our planet, information about them is scarce. For all the years of studying planetary nebulae they were only discovered the 17 chemical elements, and for the past quarter of a century no news in this sense, far from the edges have been reported. And here are the instruments aboard the "Soyuz-13", irrefutably established the presence of a planetary nebula is still two elements, aluminum and titanium.

Thus, neither the planet nor her closest companion, nor other heavenly bodies have no right to complain about the absence of titanium. But you still need to extract the metal from the ore and bring it to a state in which it can be used in modern technology. This task is very difficult.

The fact that the Union of titanium with oxygen (namely in the form of such connection element usually occurs in nature) is one of the most durable in chemistry. No electric current or high temperature not able to pull the titanium from the embrace of oxygen. This has led scientists to look for detours obtain titanium in free form. In 1940, American scientist Kroll managed to develop so-called magnesium method of industrial production of titanium. The essence of it consists in the following. First, the titanium oxide with chlorine and carbon transferred to the titanium tetrachloride. To cope with chlorine, which now takes the place of oxygen, is much easier; this task quite successfully solves, for example, an element such as magnesium. In the reaction of titanium tetrachloride with magnesium is formed spongy mass consisting of titanium, magnesium and magnesium chloride. Melted in vacuum or in an atmosphere of inert gas to the metal not included nitrogen and oxygen) this mass is converted into pure compact titanium. To obtain highly pure titanium use ideny method proposed is already known to us by van Arkel and de Boer.

To make titanium cheaper, and therefore more available, this task is today specialized research institutes, the number of which is constantly growing. Not so long ago a new Institute of light metals was established in Cleveland (USA). Interestingly, at the opening ceremony of the traditional ribbon, stretched in front of the entrance to the Institute, was made of... titanium. In order to cut, the mayor of the city instead of scissors was forced to use the gas burner and protective goggles.

In our day-to-titanium riveted the attention of thousands of scientists. In many laboratories the samples of this metal is daily subjected to cruel torture: it torn to pieces, bend, boiled in acid and alkali, heat, cooled to very low temperatures, affect him monstrous loads, high frequency, ultrasound.

And Titan reveals its secrets rights...

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