Aluminum is a volatile metal. Winged metals and alloys. Questions for self-control

According to the nature of the combustion of metals, they are divided into two groups: volatile and non-volatile. Volatile metals have relatively low phase transition temperatures - the melting point is less than 1000 K, the boiling point does not exceed 1500 K. This group includes alkali metals (lithium, sodium, potassium, etc.) and alkaline earth metals (magnesium, calcium). The phase transition temperatures of non-volatile metals are much higher. The melting point, as a rule, is above 1000 K. and the boiling point is above 2500 K (Table 1).

The combustion mechanism of metals is largely determined by the state of their oxide. The melting point of volatile metals is much lower than the melting point of their oxides. In this case, the latter are rather porous formations.

When the ignition source is brought to the surface of the metal, it evaporates and oxidizes. When the vapor concentration is equal to the lower concentration limit, they ignite. The zone of diffusion combustion is established near the surface, a large proportion of the heat is transferred to the metal, and it is heated to the boiling point. The resulting vapors, freely diffusing through the porous oxide film, enter the combustion zone. Boiling of the metal causes periodic destruction of the oxide film, which intensifies combustion. Combustion products (metal oxides) diffuse not only to the metal surface, contributing to the formation of an oxide crust, but also to the surrounding space, where, condensing, they form solid particles in the form of white smoke. The formation of white dense smoke is a visual sign of burning volatile metals.

Table 1

	Chemical		Temperature melting, K		Temperature boiling, K
non-volatile

In non-volatile metals with high phase transition temperatures, during combustion, a very dense oxide film is formed on the surface, which adheres well to the metal surface. As a result, the rate of diffusion of metal vapor through the film is sharply reduced and large particles, such as aluminum and beryllium, are not able to burn. As a rule, fires of such metals occur when they are in the form of chips, powders and aerosols. Their combustion occurs without the formation of dense smoke. The formation of a dense oxide film on the metal surface leads to particle explosion. This phenomenon is especially often observed when a particle moves in a high-temperature oxidizing medium; it is associated with the accumulation of metal vapors under the oxide film, followed by its sudden rupture. This, of course, leads to a sharp intensification of combustion.

The main parameters of their combustion are the time of ignition and combustion. From the theory of diffusion combustion it follows that the combustion time of a metal particle t g is proportional to the square of its diameter d o . Experimental data show that the actual dependence is somewhat different from the theoretical one. So, for aluminum t g ~d o 1.5÷1.8, magnesium t g ~d o 2.6, and for titanium t g ~d o 1.59.

Increasing the concentration of oxygen in the atmosphere intensifies the combustion of the metal. Aluminum particles with a diameter of (53 ÷ 66) 10 -3 mm in an atmosphere containing 23% oxygen burn out in 12.7 10 -3 s, and with an increase in the concentration of the oxidizing agent to 60% - in 4.5 10 -3 s.

However, for fire engineering calculations, of great interest is not the time of combustion of a metal particle, but the speed of flame propagation along the flow of a suspension of metal particles in an oxidizer. Table 2 shows the experimental data on the flame propagation speed and the mass burnout rate of a suspension of particles with diameters less than 10 -2 mm and 3·10 -2 mm of aluminum in air at different excess air ratios.

table 2

aluminum concentration,	Excess air ratio	Flame propagation speed, m/s		Mass burnout rate, kg/(m 2 s)
		d< 10 -2 mm	d< 3 10 -2 mm	d< 10 -2 mm	d< 3 10 -2 mm

Analysis of the data in Table 2 allows us to draw the following conclusions.

1. As the particle size of the fuel in the air increases, the speed of flame propagation decreases.

2. When the composition of the combustible mixture (metal-air) approaches the stoichiometric one (α=1), the flame propagation speed increases.

3. The burning rate of a suspension of metal particles in air is of the same order with the normal speed of flame propagation through stoichiometric mixtures of saturated hydrocarbons in air - 0.4 m/s (Table 2).

The combustion of metals is possible not only in an oxidizing environment, but also in the combustion products of organic substances. In this case, combustion proceeds due to the exothermic reaction of reducing water to hydrogen, and carbon dioxide to its oxide according to the reaction:

2Al + 3H 2 0 \u003d Al 2 O 3 + ZH 2 + 1389.4 kJ / mol;

2Al + 3CO 2 \u003d Al 2 O 3 + 3CO + 1345.3 kJ / mol.

Candidate of Technical Sciences A. ZHIRNOV, Deputy CEO VIAM.

Science and life // Illustrations

Science and life // Illustrations

The eight-engine giant ANT-20 ("Maxim Gorky") was built, like many metal aircraft of the early 1930s, from corrugated aluminum.

When using the traditional D-16 alloy, the Tu-154 passenger aircraft turned out to be too heavy.

The welded body of the MiG-29 aircraft is made of aluminum-lithium alloy 1420.

Massive and very important parts of the chassis of modern transport and passenger aircraft of OKB im. S. V. Ilyushin are made of titanium alloy VT-22. In the photo: IL-76.

Steel and aluminium, titanium and plastics, adhesives and wood, glass and rubber - no aircraft can fly without these materials. All of them are developed or tested in VIAM

Each turbine blade jet engine the most advanced metallurgical technologies are embodied. The cost of one monocrystalline blade is commensurate with the price of an expensive passenger car

The testing center is the "small academy of sciences" of VIAM. Does metal fatigue threaten to destroy an aircraft? How to find hidden defects in metal? What properties does new material? The employees of the Test Center understand all this.

Arm wrestling as a way to resolve a scientific dispute, or How N. S. Khrushchev flew to America

- "Aged" material does not mean "old"

How to cut a "fur coat" for "Buran"

Turbine blades are protected from high temperatures by plasma

The more perfect the aircraft, the more non-metallic materials it contains. Planes have already been designed, two-thirds consisting of composite materials and plastics

Laboratory assistant in the morning, student in the evening. And all this - without leaving the native laboratory. If the state does not train specialists, they have to be trained on the spot

Corrosion is the enemy of any metal. Even stainless steel rusts. How to treat ulcers on the body of "Worker and Collective Farm Woman"?

You can glue anything. All you need is the right glue. Glued planes fly in the sky, and these are not children's models, but large transport aircraft.

The first steps of our aviation are connected with the purchase of foreign aircraft. They were mostly wooden, the fuselage and wings were covered with fabric. Of course, such "cloth" aircraft could not withstand significant speed and temperature loads, other materials were needed, primarily metal.

The idea to build aircraft from aluminum originated in Germany. The first alloys designed specifically for aircraft appeared there. They were called Duralumins. A similar alloy was created in our country in the mid-20s. He received the brand D-1 - an alloy of aluminum with copper and a small amount of magnesium.

In 1932, Academician A. A. Bochvar developed the theory of recrystallization of aluminum alloys, which formed the basis for the creation of light alloys. By that time, there was a production base in the country: the first aluminum plant "Kolchugaluminy" (located in the village of Kolchugino, Vladimir Region) produced smooth and corrugated sheets of technical aluminum - this is aluminum with small additions of manganese and magnesium. Such aluminum had sufficient strength, was ductile, and therefore was used for sheathing the fuselages of aircraft.

However, the material for the new high-speed aircraft had to have completely different qualities. And some time later, in the laboratory of aluminum alloys of VIAM (created simultaneously with the opening of the institute in 1932), the D-16 alloy was developed, which was used in aircraft construction almost until the mid-80s. It is an aluminum-based alloy with a content of 4-4.5% copper, about 1.5% magnesium and 0.6% manganese. Almost any aircraft parts could be made from it: skin, power set, wing.

But the speed and altitude of flights grew. High-strength alloys were required. In the mid-1950s, Academician I. N. Fridlyander, who headed the laboratory of aluminum alloys, together with his colleagues V. A. Livanov and E. I. Kutaytseva, developed the theory of alloying high-strength alloys. The introduction of zinc and magnesium into the aluminum-copper system made it possible to sharply increase the strength of the material. This is how the V-95 alloy appeared, which has a strength of 550-580 MPa (~ 5500-5800 kgf / cm 2) and at the same time has good ductility. He had one flaw: insufficient corrosion resistance, which, however, was eliminated by two-stage artificial aging.

The new alloy was not immediately recognized by aircraft manufacturers. At this time, A. N. Tupolev created a new passenger liner Tu-154. The project did not fit into the specified weight characteristics in any way, and then general designer he called Friedlander himself, asking for help, to which he, of course, offered to use a new alloy. The project of the new car was reworked. Alloy B-95 found its way into the upper surface of the wing, and molded panels and stringers were made from it, significantly reducing the weight of the aircraft. Similar studies were going on in parallel in the USA. Alloys of the 7000 series appeared there, in particular, alloy 7075 is a complete analogue of our alloy.

The loads that an aircraft wing experiences are unequal. If the top of the wing works mainly in compression, then the lower part works in tension. Therefore, it was still made from D-16 duralumin, which has higher ductility and fatigue threshold. But even this alloy has undergone a serious modification by increasing the purity of impurities during casting of ingots. Technological improvements were so significant that actually a new material appeared - alloy 1163, which is still successfully used in the lower wing skins and the entire fuselage.

Increasing the operational life of aircraft has always been and remains the number one task. It is possible to achieve even greater reliability and durability of materials by changing the structure of the metal - "grinding the grain". For this, small amounts (up to 0.1%) of zirconium were introduced into the alloys. The grain size of the metal really decreased sharply, the resource increased. At the same time, special forging alloys were created, designed for the most critical, load-bearing structures of liners. This is how the 1933 alloy was developed, superior in its parameters to foreign analogues. Parts of the power set and frames are made from it. Experts from the European aircraft manufacturer Airbus tested the new material and decided to use it in their A-318 and A-319 series aircraft.

Unfortunately, the process of very beneficial cooperation has been put on hold. The reason is that the shares of the two main Russian producers of aluminum products - the Samara and Belokalitvensky metallurgical plants - were bought out by the American firm ALKO. A significant part of the equipment at the enterprises has been dismantled, the technological chain has been broken, qualified personnel have dispersed, and production has actually ceased. Now these enterprises produce mainly foil, which is used for the manufacture of food cans and packaging ...

And although at present, through Russian government between the company "ALCOA-RUS" (it is now called so), VIAM and aviation design bureaus, agreements were reached on resuming the production of materials so necessary for our aviation industry, the recovery process is extremely slow and painful.

VIAM became the ancestor of a series of low density alloys. This is a completely new class of materials containing lithium. The first such alloy was created by academician I. N. Fridlyander with his students back in the 60s - a quarter of a century earlier than anywhere else in the world. Its practical use, however, was initially limited: such an active element as lithium requires special smelting conditions. The first industrial aluminum-lithium alloy (its grade 1420) was created on the basis of the aluminum-magnesium system with the addition of 2% lithium. It was used in the design bureau of A. S. Yakovlev in the construction of vertical take-off aircraft for carrier-based aviation - it is for such structures that saving weight is of particular importance. The Yak-38 is still in operation, and there are no complaints about the alloy. Furthermore. It turned out that parts made of this alloy have increased corrosion resistance, although aluminum-magnesium alloys themselves are little susceptible to corrosion.

Alloy 1420 can be welded. This property was used to create the MiG-29M aircraft. The gain in weight during the construction of the first prototypes of the aircraft due to the reduced density of the alloy and the exclusion of a large number of bolted and riveted joints reached 24%!

At present, specialists from Airbus are very interested in the modification of this alloy - alloy 1424. At the plant in the city of Koblenz (Germany), wide sheets 8 m long were rolled out of the alloy, from which full-size fuselage structural elements were made. Stiffeners from the same material were welded by laser welding, and the elements were joined together by friction welding, after which they were sent for life tests in France. Despite the fact that some parts were intentionally damaged (to assess performance in an extreme situation), after 70 thousand load cycles, the design completely retained its operational properties.

Another alloy with lithium, created at VIAM, is 1441. Its main feature is that it can be used to make coil-rolled sheets with a thickness of 0.3 mm while maintaining high strength qualities. The Beriev Design Bureau used the alloy to make the skin of its Be-103 seaplane. This small - only for four people - car, the skin thickness of which is 0.5-0.7 mm, is produced by a plant in Komsomolsk-on-Amur. Its weight is 10% less than similar models from traditional materials. A batch of such aircraft has already been bought by the Americans.

Thin, but strong rolled products are needed to create a new class of materials that has recently appeared - laminated aluminum-glass-reinforced plastics, which are called "sial" in Russia, and "glair" abroad. The material is a multilayer structure: alternating layers of aluminum and fiberglass. It has many advantages over monolithic ones. Firstly, fiberglass can be reinforced with artificial fibers, increasing strength by a third. But the main advantage is that if a crack appears in the structure, it grows an order of magnitude slower than in monolithic materials. This is what sials, or glairs, first of all interested aircraft manufacturers in. For the first time, the upper part of the fuselage skin of the Airbus A-380 was made from such material in the most critical places - in front of the wing and after the wing. Life tests have shown that a crack in such a material practically does not grow under working loads. Therefore, glares can be used as stoppers to prevent the growth of cracks in the form of inserts in the upper fuselage skins, where particularly high reliability and a long service life are required.

Titanium, like aluminum, also has the right to be called heavenly or winged. The laboratory of titanium alloys was established at the institute in 1951. Its founder, Professor S. G. Glazunov, invented a titanium casting plant and, in fact, created the first titanium alloy. The second such installation was built with the help of VIAM at the All-Union Institute of Light Alloys (VILS), and then together we implemented the developed technological processes at the metallurgical plant in Verkhnyaya Salda, which is now the main producer of titanium products in the country. In Soviet times, the plant produced more than 100 thousand tons of such products. After the collapse of the USSR, production decreased several times. The new director of the plant, V.V. Tyutyuhin, had to make great efforts to rectify the situation. After a sharp decline in production, the plant began to rise. Now the output of titanium products is 25 thousand tons per year. Most of it (about 80%) is supplied abroad on orders from leading aircraft manufacturing concerns. In connection with the revival of the aircraft industry in Russia, there was an urgent need to create an alternative production. It is unprofitable for a giant, such as the plant, to produce small batches of products. The orders of Russian aircraft manufacturers are still small - 3-5 tons, and the manufacturing cycle is very long and reaches up to a year. Such production can be created on the basis of VIAM, VILS and the Stupino metallurgical plant, where, in fact, ingots obtained from Verkhnyaya Salda are processed.

More than fifty titanium alloys for various purposes have been created at VIAM, of which about thirty are used in series today. Now the proportion of titanium alloys in an aircraft, depending on its type and purpose, ranges from 4 to 10-12%. High-strength titanium alloys, such as VT-22, have been used for more than a quarter of a century for the manufacture of welded chassis of the Il-76 and Il-86. These complex, massive parts in the West are starting to be made of titanium only now. In rocket technology, the proportion of titanium is much higher - up to 30%.

High-tech alloys VT-32 and VT-35 created at VIAM are very plastic in the annealed state. They can be molded into complex parts, which, after artificial aging, acquire extremely high strength. When the Tu-160 strategic bomber was being created at the Tupolev Design Bureau in the early 1970s, a special workshop was built at the Moscow plant "Experience" for the manufacture of titanium parts of the center section. These planes are still flying, however, only one squadron of them remains in Russia.

Today, VIAM is faced with the task of creating titanium alloys that work reliably at temperatures of 700-750 o C. Unfortunately, all the metallurgical possibilities used to create traditional alloys have already been implemented. New approaches are required. In this direction, research is underway in the laboratory to create the so-called intermetallic compounds based on titanium - aluminum.

Aluminum-beryllium alloys (they are called ABM) have been researched and created at our enterprise for 27 years. The first aircraft using such an alloy was built by designer P. V. Tsybin.

ABM alloys favorably differ from other aluminum alloys in higher fatigue strength and unique acoustic endurance. Now they have found application in welded structures. spacecraft, including in a series of well-known interplanetary stations "VENERA".

Beryllium itself is also interesting, in which the elastic modulus is 30-40% higher than that of high-strength steels, and the thermal expansion coefficients are close, which made it possible to use it in gyroscopes.

VIAM has developed a technology for manufacturing thin vacuum-tight foil and disks and plates from it. A technology for soldering such foil with other structural materials has been developed, and mass production units of x-ray machines for both Russian enterprises and foreign firms.

Another branch of ours was organized in the Volga region in the early 1980s, during the creation of the largest aviation plant in Ulyanovsk, which produced aviation giants - Ruslans and Mriyas. For the technological support of these aircraft, a special laboratory was created.

One of its tasks is the introduction of composite materials into the aircraft industry. This is the near future of aircraft construction. For example, the Boeing 787, which is being prepared for production in two years, will consist of 55-60% composite materials. The entire airframe: fuselage, wing, plumage - is built from composite materials - carbon fiber. The share of aluminum will be reduced to 15%. CFRP is an extremely attractive material for aircraft builders. They have high specific strength, low weight, and fairly decent resource characteristics. The threat of destruction due to the formation of cracks is reduced by orders of magnitude. Although, of course, in relation to these materials there are a number of issues that have not yet been resolved. It was found, for example, that corrosion develops at the point of contact between carbon fiber and aluminum due to the occurrence of a galvanic couple. Therefore, in such places, aluminum had to be replaced with titanium.

When the Ulyanovsk branch was created, the share of composite materials in the design of domestic aircraft was not very large. Nevertheless, we slowly began to teach the work of technologists, workers ... Then they came hard times, the entire plant was on the verge of closing, but the branch survived. Gradually, production was restored, and although it is still half mothballed, there are several orders for the Tu-204, there are orders from Germany for the production of Ruslans. So, there is a field of activity for our laboratory.

The second line of work of the Ulyanovsk branch is special, erosion- and corrosion-resistant coatings.

During the decomposition of organometallic liquids in a vacuum, coatings of chromium and chromium carbides are formed on the surfaces. By adjusting the process, it is possible to obtain coatings containing any ratio of these components - from pure chromium to pure carbides. The hardness of the chrome coating is 900-1000 MPa, the hardness of the carbide coating is twice as high - about 2000 MPa. But, the higher the hardness, the greater the brittleness. Between these extremes and find the desired in each individual case.

Nanotechnology provides another way to achieve the desired results. Nanoparticles of carbides and metal oxides with a size of 50 to 200 nm are introduced into chromium-containing galvanic baths. The highlight of the process is that these particles themselves are not included in the composition of the coating. They only enhance the activity of the deposited component, create additional centers crystallization, due to which the coating is denser, more corrosion-resistant, has better anti-erosion properties.

And in conclusion, about one more unique quality of the institute: in the USSR there was a good system that reliably guaranteed the quality of the final product of the enterprise. In VIAM, this system has been preserved to this day. If a design bureau or a private company purchases a product, they prefer to submit it to VIAM for testing before use. We are still trusted.

See in a room on the same topic

So far, we have been talking about metals that "work" mainly on Earth. Mainly about ferrous metals. This is natural: iron, steel and cast iron helped people create a modern civilization. Until the beginning of our century, iron and its alloys played a leading role in industry. This role has not been lost even now, but in the 20th century, other metals - non-ferrous - begin to acquire more and more importance. Again, copper became very valuable and necessary. The metal of ancient bronze tools turned out to be indispensable for electrical engineering. The windings of transformers and electric generators, power lines, electrical wiring inside cars and buildings are all made of copper. Then other metals came to the fore, which helped man to conquer first the air, and then the airless space.

The first planes had a wooden frame covered with fabric. They were derisively called "flying whatnots". But this lightweight design fully met its purpose, as long as flight speeds did not exceed 150 kilometers per hour. Then the speeds increased - and the planes began to break apart in the air. Wings and empennage broke, fuselages fell apart ... It became clear that the wooden frame had to be disposed of. What can replace wood and fabric? The material needed was much stronger, but just as light. After all, the entire history of aviation is, in fact, a struggle with weight. The lighter the aircraft, the faster it will fly, the more payload it can pick up.

The first flying metal was aluminum - the most common metal in the earth's crust. Its reserves are practically inexhaustible. Aluminum is a good conductor of heat and electricity, second only to silver, copper and gold. But according to specific gravity it is much lighter than these metals.

Aluminum would be good for everyone, but the trouble is - it is fragile, soft. You can't make airplanes out of it. And in general, nothing can be done except dishes. Therefore, its use was very limited. And when it had just been discovered and began to be obtained in laboratory conditions, they did not know at all what this metal could be used for.

I remember reading in an old book about an unexpected application that the Russian Tsar found for aluminum. For the detachment of grenadiers, which was supposed to attend the celebrations in Paris, they made aluminum helmets. The furore was extraordinary. The Parisians gasped, thinking how rich the Russian tsar was if he made helmets ... from silver (at that time, the general public almost did not know about aluminum). The Parisians were mistaken: aluminum helmets were then much more expensive than silver ones. Unfortunately, I could not find confirmation of this fact anywhere, therefore I cite it as a semi-legend.

But back to aircraft. If it is impossible to make them from pure aluminum, then maybe from its alloys? On the example of iron and steel, we know that alloys can be tens of times stronger than the main of their constituent metals. Is it possible to create strong and light alloys based on aluminum?

Many scientists have worked on this problem. They groped their way, trying one by one all the substances known at that time. The German researcher Alfred Wilm was the first to stumble upon the correct solution. After hundreds of experiments, he found that copper and magnesium, introduced in certain proportions into aluminum, increase its strength by three to five times. This is not as much as we would like, but it gives hope for further success. Is it possible to harden the resulting alloys to make them even stronger? True, it is widely believed that of all metals only steel and, under certain conditions, copper and bronze can be hardened, but why is it necessary to believe the popular opinion?

Wilm heated the alloy to 500 degrees and lowered it into water. Yes, measurements have shown that a hardened alloy is stronger than an unhardened one. But how much? Surprisingly, the device each time showed a new value. The device is faulty, the scientist decided, and gave it for verification. A few days later, having received a carefully calibrated device, Wilm repeated the measurements. The strength of the alloy has doubled.

And then it dawned on the scientist: strength increases after exposure. Wilm placed the thin section under a microscope, and all doubts were dispelled: after exposure, the alloy acquired a fine-grained structure.

There was something to be surprised: after all, it seems that everything was already known about hardening. Since the time of Homer, people have been hardening metal products to give them strength. And yet, nature has demonstrated a new, unknown property of metals: some of them are hardened not during hardening, but after it.

So, the technology was determined: the alloy was quenched and held for five to seven days. In general, the strength compared to pure aluminum increases by about ten times. You can make planes!

Wilm sold his patent to a German company, which began to produce an alloy, calling it "duralumin", which means strong aluminum. With us, this name has been transformed into duralumin, or, simply, into duralumin.

Volatile compounds are those that can evaporate and condense without changing their composition at moderate (below 700–800 K) temperatures. Signs of volatility: the possibility of sublimation (sublimation) of the substance; the presence in the mass spectrum of molecular compounds or fragmented metal-containing ions.

Volatile metal compounds can be divided into several classes:

1) complexes with monodentate-donor ligands (halides);

• 2) borohydrides;
• 3) chelates (N-diketonates and their derivatives, dialkyldithiocarbamates, complexes with macrocyclic ligands);
• 4) anhydrous nitrates, perchlorates;

5) complexes with ligands of the r-acceptor type (cyclopentadienyl complexes);

6) mixed ligand complexes. Here DPM is dipivaloylmethane; HFA - hexafluoroacetone; TTA - thenoyltrifluoroacetone; TBP is tributyl phosphate.

It can be noted that compounds with a molecular structure with a clearly expressed covalent nature of the chemical bond and a formally zero oxidation state of the metal, or, for example, compounds of polyvalent metals in the highest oxidation state, in which the central metal ion is completely shielded, have the maximum volatility. The greatest variety of volatile compounds are characterized by d- and p-elements, the smallest - by heavy alkali and alkaline earth metals. Thus, the properties of volatility of a particular compound are closely related to its chemical structure. Volatile complex compounds are used in gas chromatography, mass spectrometric analysis, separation and concentration by sublimation.

Solubility of complexes.

The solubility of substances is determined by the ratio of free energies of crystal lattice formation and solvation. Both that and other energy depend on the structure of the substance and the nature of the solvent. Thus, in highly polar solvents (water), the solubility of complexes generally decreases in the following order: charged » uncharged hydrophilic > uncharged hydrophobic complexes. For organic non-polar solvents, the solubility series is opposite.

For charged complexes (including ion associates), solubility in water generally increases with the charge of the ion, for example

decreases as its size increases:

For uncharged complexes, the solubility depends significantly on the ratio of hydrophilic and hydrophobic fragments. Thus, among chelates, solubility in water is, as a rule, lower for coordinatively saturated compounds, i.e., those in which all the coordination sites of the central atom are occupied by a chelating agent. For example, among the Ni(II), Fe(II), Сu(II), Co(II) complexes with dimethylglyoxime () with the composition М:L = 1:2, the water solubility of nickel(II) dimethylglyoximate is significantly lower than that of the others. The reason is that nickel with this reagent forms a coordinatively saturated planar square complex with CN = 4 of the composition, while Fe(II), Cu(II), Co(II) are coordinatively unsaturated octahedral complexes. However, if the organic part of the ligand is sufficiently large, hydrophobic, and can block hydrophilic groups, then coordinatively unsaturated complexes can be very slightly soluble in water. For example, the solubility in water of most coordinatively unsaturated hydrophobic 8-hydroxyquinolinates of doubly charged ions of the composition is lower than for the coordinatively saturated but hydrophilic Cu(II) complex with aminoacetic acid:

The introduction of heavy hydrophobic substituents (weighting effect) into a chelate or ion associate molecule is widely used in analytical chemistry. Thus, the use of heavy organic cations makes it possible to precipitate even relatively simple inorganic complexes in the form of ionic associates. For example, from dilute solutions, either the naphthoquinolinium cation precipitates the complex quantitatively. However, it should be borne in mind that the introduction of substituents - even hydrophobic ones - in a position close to the donor atoms of the chelate-forming groups can cause steric hindrance during complexation and lead to an undesirable result. Thus, due to steric hindrance caused by the methyl group, only two molecules of 2-methyl-8-hydroxyquinoline (HL) can attach to the Al(III) ion. As a result, a complex of composition is formed, which is charged and highly soluble in water.

Unusual production was developed at the site of the former Lomovsky mine, not far from Kirovgrad. Here, the former specialists of the local giant, the copper smelter, organized the production of various products from aluminum alloys. More precisely - from composite materials.

For two decades there has been no mining of copper ore at Lomovka. However, this is the only one of the whole wreath of former raw materials sources of the Kirovgrad copper smelter, which was lucky to continue its useful existence. True, in a completely new quality. Of course, the mines and workings, somehow buried by the former owners, oozing with sulfuric acid streams, no longer bother anyone with their presence. But part of the ground buildings is the property of Composite Materials LLC. Reconstructed, they serve as an industrial site for this unusual manufacturing company.

Here, in our production and storage facilities, the foot of a journalist has not yet set foot, - the director of the enterprise Lev Cherny jokes, who is clearly amused by our amazement: you blow into a deaf metal test tube, but it seems that this is a tube with a hole at the other end. There is, of course, no hole, but air ... exits through the pores in the metal.

At this enterprise, a special material is produced using casting - porous aluminum. Filters and mufflers are also made from it, which are used in oil and gas production and chemical equipment, automotive, aviation and railway equipment, in general and special engineering products. Lomov mufflers successfully work in braking systems trucks and buses. Unique products from the "new" Lomovka are known and purchased by more than two hundred domestic and foreign machine-building firms. Among the organizations that operate products made of porous aluminum are OAO Sibneft, OAO Kurgankhimmash, OAO Transpnevmatika, OAO RAAZ AMO ZIL, OAO Salavatgidromash, OAO Pnevmatika and others Russian enterprises, as well as companies from Belarus and Kazakhstan, the Baltic republics and Germany, Switzerland and the USA ...

Aluminum is called a "volatile metal". In this sense, porous aluminum is doubly "volatile". It weighs almost nothing. You pick up a workpiece, and it is as if made of foam. But most importantly - the market is in demand. As they say, fly away! So in this sense, the metaphor is much more appropriate.

We participated in many specialized exhibitions, visited the largest international specialized exhibition "Casting and Welding" in Hannover. So nowhere, including in Hannover, we have not seen anything like our products, - says Lev Cherny. The company "Composite Materials" was founded with the participation of specialists from the Ural Polytechnic Institute exactly twenty years ago, at the turn of the perestroika 80s and the "troubled" 90s of the last century. However, no one then knew what the next decade would be like and how difficult the path to the dream of "own business" would be. Captured by the bold idea of ​​organizing a business for the production of an unprecedented material - an inexpensive analogue of wire, metal-ceramic and mesh materials - Lev Cherny left the post of head of the metallurgical shop of the Kirovgrad Combine. A metallurgist by education, by vocation and by inheritance from his father, who worked all his life after the war as a heater for methodical furnaces at rolling mill NTMK, Cherny got down to business, renting a small room on Lomovka.

At first, it was essentially a research and production center for the development of porous aluminum casting technology, which was proposed by my former classmate, professor at USTU-UPI, doctor of technical sciences Evgeny Furman, - says Lev Emelyanovich. - When the Lomovsky mine ceased to function, we were able to purchase buildings, found and installed unique Japanese and Czech machines, in order - for the first time in the world practice - to implement our technology on an industrial scale. We make truly unique foundry developments, actively work with global manufacturers of pneumatics in matters of noise suppression.

Small, four dozen people, labor collective, more than a quarter of which are people with engineering education, produces filtration materials and filters for various liquids and gases, as well as effective mufflers for any industrial pneumatic systems using original technology. Today Lomovka produces over 320 standard sizes of products from this unique permeable material.

The next step in the development of the company, which was not afraid to settle "away from civilization", was the development and launch of mass production of electric arc machines for metal cutting. Then - the production of reverberatory and crucible furnaces original design. And in the future... However, let's not rush tomorrow, because now we have to plan with caution.

The outgoing year, although it was an anniversary for the company, did not live so easily: the crisis waves have come here as well. The auto industry "fell" - and this immediately affected the number of orders. At some point, I even had to shorten the working week and work on a "truncated" schedule for about three months. But in New Year the team enters with a normal rhythm of life. More precisely, he enters. A significant touch: in the first years of the enterprise's existence, workers were delivered to Lomovka by a special bus. Later, the need for it disappeared: people began to come to work on own cars acquired on an honest salary. That's right: to work - out of town. There, where the forest air is so transparent, where a mountain river flows with icy water, the taste is such that you won’t get drunk.

One misfortune, grave wounds on the ground are unsightly signs of human irresponsibility with which the former owners of the Lomovsky mine treated their legal duties of soil reclamation. At one time, having abandoned the mines, and not only in Lomovka, the Kirovgrad copper-smelting giant completely forgot about the need to put the planet in order, as they say. A strange landscape with traces of mine workings and pronounced zones of collapse sometimes confuses business guests a lot - representatives of nonresident and foreign businesses interested in the products of the "new" Lomovka.

It is no coincidence that, thinking about the development of production and the establishment of worthy marketing, the management of the Composite Materials company is trying to "get through" to environmentalists and lawyers. Like it or not, the territory of the former mine must be put in order. Because it’s not worth it to treat your native land so carelessly, on which you can do so much with hands and a smart head.

By the way, Chernoy's engineers are now working on the creation of a unique pilot plant for the processing of sludge and mine waste water, which poses an unrelenting threat to the ecological well-being of the Kirovgrad region. It was not possible to find investors to implement the proven sorption technology for extracting copper, zinc and rare metals from sludge ponds and dumps. The submitted business plan for production was studied during the year in the investment structure created by the regional government, but was rejected. And yet Cherny did not give up the idea. Work on the sludge treatment plant began - without borrowed money, due to enthusiasm. Fortunately, the new owners of Lomovka have no problems with this capital.

Zinaida PANSHINA, Regional newspaper