Titanium was originally named "gregorite" by the British chemist Reverend William Gregor, who discovered it in 1791. Titanium was then independently discovered by the German chemist M. H. Klaproth in 1793. He named him a titan in honor of the titans from Greek mythology - "the embodiment of natural strength." It was not until 1797 that Klaproth discovered that his titanium was an element previously discovered by Gregor.
Characteristics and properties
Titanium is a chemical element with the symbol Ti and atomic number 22. It is a shiny metal with a silvery color, low density, and high strength. It is resistant to corrosion in sea water and chlorine.
Element meets in a number of mineral deposits, mainly rutile and ilmenite, which are widely distributed in the earth's crust and lithosphere.
Titanium is used to produce strong light alloys. The two most useful properties of a metal are corrosion resistance and a hardness to density ratio, the highest of any metallic element. In its unalloyed state, this metal is as strong as some steels, but less dense.
Physical properties of metal
it durable metal
with low density, rather ductile (especially in anoxic environment), brilliant and metalloid white. Its relatively high melting point of over 1650°C (or 3000°F) makes it useful as refractory metal. It is paramagnetic and has rather low electrical and thermal conductivity.
On the Mohs scale, the hardness of titanium is 6. According to this indicator, it is slightly inferior to hardened steel and tungsten.
Commercially pure (99.2%) titanium has a tensile strength of about 434 MPa, which is in line with conventional low grade steel alloys, but titanium is much lighter.
Chemical properties of titanium
Like aluminum and magnesium, titanium and its alloys oxidize immediately when exposed to air. It reacts slowly with water and air at ambient temperature, because it forms a passive oxide coating which protects bulk metal from further oxidation.
Atmospheric passivation gives titanium excellent corrosion resistance almost equivalent to platinum. Titanium is able to withstand the attack of dilute sulfuric and hydrochloric acids, chloride solutions and most organic acids.
Titanium is one of the few elements that burns in pure nitrogen, reacting at 800° C (1470° F) to form titanium nitride. Due to their high reactivity with oxygen, nitrogen and some other gases, titanium filaments are used in titanium sublimation pumps as absorbers for these gases. These pumps are inexpensive and reliably produce extremely low pressures in UHV systems.
Common titanium-bearing minerals are anatase, brookite, ilmenite, perovskite, rutile, and titanite (sphene). Of these minerals, only rutile and ilmenite have economic importance, but even these are difficult to find in high concentrations.
Titanium is found in meteorites and has been found in the Sun and M-type stars with a surface temperature of 3200° C (5790° F).
The currently known methods for extracting titanium from various ores are laborious and expensive.
Production and manufacturing
Currently, about 50 grades of titanium and titanium alloys have been developed and are being used. To date, 31 classes of titanium metal and alloys are recognized, of which classes 1-4 are commercially pure (unalloyed). They differ in tensile strength depending on the oxygen content, with Grade 1 being the most ductile (lowest tensile strength with 0.18% oxygen) and Grade 4 being the least ductile (maximum tensile strength with 0.40% oxygen). ).
The remaining classes are alloys, each of which has specific properties:
- plastic;
- strength;
- hardness;
- electrical resistance;
- specific corrosion resistance and their combinations.
In addition to these specifications, titanium alloys are also manufactured to meet aerospace and military equipment(SAE-AMS, MIL-T), ISO standards and country specific specifications as well as end user requirements for aerospace, military, medical and industrial applications.
A commercially pure flat product (sheet, plate) can be easily formed, but processing must take into account the fact that the metal has a "memory" and a tendency to return back. This is especially true for some high-strength alloys.
Titanium is often used to make alloys:
- with aluminum;
- with vanadium;
- with copper (for hardening);
- with iron;
- with manganese;
- with molybdenum and other metals.
Areas of use
Titanium alloys in the form of sheet, plate, rod, wire, casting find applications in industrial, aerospace, recreational and emerging markets. Powdered titanium is used in pyrotechnics as a source of bright burning particles.
Because titanium alloys have a high tensile strength to density ratio, high corrosion resistance, fatigue resistance, high crack resistance, and moderate high temperature capability, they are used in aircraft, armor, sea ships, spaceships and rockets.
For these applications, titanium is alloyed with aluminium, zirconium, nickel, vanadium and other elements to produce a variety of components including critical structural members, fire walls, landing gear, exhaust pipes (helicopters) and hydraulic systems. In fact, about two-thirds of the titanium metal produced is used in aircraft engines and frames.
Because titanium alloys are resistant to seawater corrosion, they are used to make propeller shafts, heat exchanger tooling, etc. These alloys are used in cases and components of ocean observation and monitoring devices for science and the military.
Specific alloys are applied in downhole and oil wells and nickel hydrometallurgy for their high strength. The pulp and paper industry uses titanium in technological equipment exposed to aggressive media such as sodium hypochlorite or wet chlorine gas (in bleaching). Other applications include ultrasonic welding, wave soldering.
In addition, these alloys are used in automobiles, especially in automobile and motorcycle racing, where low weight, high strength and stiffness are essential.
Titanium is used in many sporting goods: tennis rackets, golf clubs, lacrosse rollers; cricket, hockey, lacrosse and football helmets, as well as bicycle frames and components.
Due to its durability, titanium has become more popular for designer jewelry (particularly titanium rings). Its inertness makes it a good choice for people with allergies or those who will be wearing jewelry in environments such as swimming pools. Titanium is also alloyed with gold to produce an alloy that can be sold as 24 carat gold because 1% alloyed Ti is not enough to require a lower grade. The resulting alloy is about the hardness of 14 carat gold and is stronger than pure 24 carat gold.
Precautionary measures
Titanium is non-toxic even in high doses. In powder form or as metal shavings, it poses a serious fire hazard and, if heated in air, an explosion hazard.
Properties and Applications of Titanium Alloys
Below is an overview of the most commonly encountered titanium alloys, which are divided into classes, their properties, advantages and industrial applications.
7th grade
Grade 7 is mechanically and physically equivalent to Grade 2 pure titanium, except for the addition of an intermediate element of palladium, making it an alloy. It has excellent weldability and elasticity, the most corrosion resistance of all alloys of this type.
Class 7 is used in chemical processes and components production equipment.
Grade 11
Grade 11 is very similar to Grade 1, except for the addition of palladium to improve corrosion resistance, making it an alloy.
Other beneficial features include optimum ductility, strength, toughness and excellent weldability. This alloy can be used especially in applications where corrosion is a problem:
- chemical processing;
- production of chlorates;
- desalination;
- marine applications.
Ti 6Al-4V class 5
Alloy Ti 6Al-4V, or grade 5 titanium, is the most commonly used. It accounts for 50% of the total titanium consumption worldwide.
Ease of use lies in its many benefits. Ti 6Al-4V can be heat treated to increase its strength. This alloy has high strength at low weight.
This is the best alloy to use in several industries such as aerospace, medical, marine and chemical processing industry. It can be used to create:
- aviation turbines;
- engine components;
- aircraft structural elements;
- aerospace fasteners;
- high-performance automatic parts;
- sports equipment.
Ti 6AL-4V ELI class 23
Grade 23 - surgical titanium. Ti 6AL-4V ELI, or Grade 23, is a higher purity version of Ti 6Al-4V. It can be made from rolls, strands, wires or flat wires. it the best choice for any situation where a combination of high strength, low weight, good corrosion resistance and high toughness is required. It has excellent damage resistance.
It can be used in biomedical applications such as implantable components due to its biocompatibility, good fatigue strength. It can also be used in surgical procedures to fabricate these constructs:
- orthopedic pins and screws;
- clamps for ligature;
- surgical staples;
- springs;
- orthodontic appliances;
- cryogenic vessels;
- bone fixation devices.
Grade 12
Grade 12 titanium has excellent high quality weldability. It is a high strength alloy that provides good strength at high temperatures. Grade 12 titanium has characteristics similar to 300 series stainless steels.
Its ability to form in a variety of ways makes it useful in many applications. The high corrosion resistance of this alloy also makes it invaluable for manufacturing equipment. Class 12 can be used in the following industries:
- heat exchangers;
- hydrometallurgical applications;
- chemical production with elevated temperature;
- sea and air components.
Ti5Al-2.5Sn
Ti 5Al-2.5Sn is an alloy that can provide good weldability with stability. It also has high temperature stability and high strength.
Ti 5Al-2.5Sn is mainly used in the aviation industry, as well as in cryogenic installations.
Titanium - a chemical element of group IV, 4 periods periodic system Mendeleev, atomic number 22; durable and lightweight silver-white metal. It exists in the following crystalline modifications: α-Ti with a hexagonal close-packed lattice and β-Ti with a cubic body-centered packing.
Titan became known to man only about 200 years ago. The history of its discovery is connected with the names of the German chemist Klaproth and the English amateur researcher MacGregor. In 1825, I. Berzelius was the first to isolate pure metallic titanium, but until the 20th century, this metal was considered rare and therefore unsuitable for practical use.
However, by our time it has been established that titanium ranks ninth in terms of abundance among other chemical elements, and its mass fraction in the earth's crust is 0.6%. Titanium is found in many minerals, whose reserves amount to hundreds of thousands of tons. Significant deposits of titanium ores are located in Russia, Norway, the USA, in southern Africa, and in Australia, Brazil, India, open placers of titanium-containing sands are convenient for mining.
Titanium is a light and ductile silver-white metal, melting point 1660 ± 20 C, boiling point 3260 C, density of two modifications and respectively equal to α-Ti - 4.505 (20 C) and β-Ti - 4.32 (900 C) g/cm3. Titanium is characterized by high mechanical strength, which is maintained even at high temperatures. It has a high viscosity, which during its machining requires the application of special coatings on the cutting tool.
At ordinary temperatures, the surface of titanium is covered with a passivating oxide film, which makes titanium corrosion-resistant in most environments (with the exception of alkaline). Titanium chips are flammable, and titanium dust is explosive.
Titanium does not dissolve in dilute solutions of many acids and alkalis (except for hydrofluoric, orthophosphoric and concentrated sulfuric acids), but in the presence of complexing agents it easily interacts even with weak acids.
When heated in air to a temperature of 1200C, titanium ignites, forming oxide phases of variable composition. Titanium hydroxide precipitates from solutions of titanium salts, the calcination of which makes it possible to obtain titanium dioxide.
When heated, titanium also interacts with halogens. In particular, titanium tetrachloride is obtained in this way. As a result of the reduction of titanium tetrachloride with aluminum, silicon, hydrogen and some other reducing agents, titanium trichloride and dichloride are obtained. Titanium interacts with bromine and iodine.
At temperatures above 400C, titanium reacts with nitrogen to form titanium nitride. Titanium also reacts with carbon to form titanium carbide. When heated, titanium absorbs hydrogen, and titanium hydride is formed, which decomposes with the release of hydrogen when heated again.
Most often, titanium dioxide with a small amount of impurities acts as a starting material for the production of titanium. This can be both titanium slag obtained during the processing of ilmenite concentrates, and rutile concentrate, which is obtained during the enrichment of titanium ores.
Titanium ore concentrate is subjected to pyrometallurgical or sulfuric acid processing. The product of sulfuric acid treatment is titanium dioxide powder. When using the pyrometallurgical method, the ore is sintered with coke and treated with chlorine to produce titanium tetrachloride vapor, which is then reduced by magnesium at 850C.
The resulting titanium "sponge" is remelted, the melt is cleaned of impurities. For titanium refining, the iodide method or electrolysis is used. Titanium ingots are obtained by arc, plasma or electron beam processing.
Most of the titanium production goes to the needs of the aviation and rocket industries, as well as marine shipbuilding. Titanium is used as an alloying addition to quality steels and as a deoxidizer.
Various parts of electrovacuum devices, compressors and pumps for pumping aggressive media, chemical reactors, desalination plants and many other equipment and structures are made from it. Due to its biological safety, titanium is an excellent material for applications in the food and medical industries.
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The thermal conductivity of titanium is - 14 0 W / m deg, which is somewhat lower than the thermal conductivity of alloy steel. The material is well forged, stamped, machined. Titanium products are welded with a tungsten electrode in a protective argon atmosphere. Recently, titanium has been used for the manufacture of a wide range of pipes, sheets, rolled products.
The thermal conductivity of titanium is low - about 13 times lower than aluminum and 4-4 times lower than iron.
The thermal conductivity of titanium is close to that of stainless steel and is 14 kcal/m C hour. Titanium is well forged, stamped and machined satisfactorily. At temperatures above 200 C, it tends to absorb gases. Titanium is welded with a tungsten electrode in a protective argon atmosphere.
The thermal conductivity of titanium and its alloys is about 15 times lower than that of aluminum, and 35-5 times lower than that of steel. The coefficient of linear thermal expansion of titanium is also significantly lower than that of aluminum and stainless steel.
The thermal conductivity of titanium is - 14 0 W / (m - K), which is somewhat lower than the thermal conductivity of alloy steel. The material is well forged, stamped, machined. Titanium products are welded with a tungsten electrode in a protective argon atmosphere. Recently, titanium has been used for the manufacture of a wide range of pipes, sheets, rolled products.
The thermal conductivity coefficient of titanium in the operating temperature range (20 - 400 C) is 0 057 - 0 055 cal / (cm-s - C), which is about 3 times less than the thermal conductivity of iron, 16 times less than the thermal conductivity of copper and close to the thermal conductivity of stainless steels austenitic grade.
Therefore, for example, the thermal conductivity of titanium is 8 - 10 times less than the thermal conductivity of aluminum.
The obtained calculated values of the phonon thermal conductivity of titanium coincide with the estimate of this value made in the work, where it is taken equal to 3 -: - 5 W / m-deg.
With alloying, as well as with an increase in the content of impurities, the thermal conductivity of titanium, as a rule, decreases. When heated, the thermal conductivity of alloys, like pure titanium, increases; already at 500 - 600 C, it approaches the thermal conductivity of unalloyed titanium.
The modulus of elasticity of titanium is almost half that of iron, is on the same level with the modulus of copper alloys and is much higher than that of aluminum. The thermal conductivity of titanium is low: it is about 7% of the thermal conductivity of aluminum and 165% of the thermal conductivity of iron. This must be taken into account when heating metal for forming and welding. The electrical resistance of titanium is about 6 times greater than that of iron and 20 times greater than that of aluminum.
First of all, it must be taken into account that the thermal conductivity of titanium and its alloys at low temperatures is very low. At room temperature, the thermal conductivity of titanium is approximately 3% of the thermal conductivity of copper and is several times lower than, for example, that of steels (the thermal conductivity of titanium is 0 0367 cal / cm sec C, and the thermal conductivity of steel 40 is 0 142 cal. With increasing temperature, the thermal conductivity of titanium alloys increases and approaches the thermal conductivity of steels.This affects the heating rates of titanium alloys depending on the temperature to which they are heated, as can be seen from the heating and cooling rates of commercially pure titanium (VT1 alloy) with a cross section of 150 mm (Fig.
Titanium has a low thermal conductivity, which is 13 times less than the thermal conductivity of aluminum and 4 times less than the thermal conductivity of iron. With an increase in temperature, the thermal conductivity of titanium decreases somewhat and at 700 C it is 0 0309 cal/cm sec SS.
Titanium has a low thermal conductivity, which is 13 times less than the thermal conductivity of aluminum and 4 times less than the thermal conductivity of iron. With an increase in temperature, the thermal conductivity of titanium decreases somewhat and at 700 C it is 0 0309 cal / cm sec C.
When fusion welding to obtain a joint good quality Reliable protection from atmospheric gases (O2, Nj, H2) of the metal of the welded joint heated to a temperature above 400 C on both sides of the weld is required. Grain growth is exacerbated by the low thermal conductivity of titanium, which increases the residence time of the weld metal at high temperatures. To overcome these difficulties, welding is performed at the lowest possible heat input.
The most significant for the national economy were and remain alloys and metals, combining lightness and strength. Titanium belongs to this category of materials and, in addition, has excellent corrosion resistance.
Titanium is a transition metal of the 4th group of the 4th period. Molecular mass it is only 22, which indicates the lightness of the material. At the same time, the substance is distinguished by exceptional strength: among all structural materials, it is titanium that has the highest specific strength. Color is silvery white.
What is titanium, the video below will tell:
Concept and features
Titanium is quite common - it takes 10th place in terms of content in the earth's crust. However, it was only in 1875 that a truly pure metal was isolated. Prior to this, the substance was either obtained with impurities, or its compounds were called metallic titanium. This confusion led to the fact that the metal compounds were used much earlier than the metal itself.
This is due to the peculiarity of the material: the most insignificant impurities significantly affect the properties of a substance, sometimes completely depriving it of its inherent qualities.
Thus, the smallest fraction of other metals deprives titanium of heat resistance, which is one of its valuable qualities. And a small addition of a non-metal turns a durable material into a brittle and unsuitable for use.
This feature immediately divided the resulting metal into 2 groups: technical and pure.
- The first are used in cases where strength, lightness and corrosion resistance are most needed, since titanium never loses the last quality.
- High purity material used where a material is needed that works under very high loads and high temperatures, but at the same time is lightweight. This, of course, is aircraft and rocket science.
The second special feature of matter is anisotropy. Some of it physical qualities change depending on the application of forces, which must be taken into account when applying.
Under normal conditions, the metal is inert, does not corrode either in sea water or in sea or city air. Moreover, it is the most biologically inert substance known, due to which titanium prostheses and implants are widely used in medicine.
At the same time, when the temperature rises, it begins to react with oxygen, nitrogen, and even hydrogen, and absorbs gases in liquid form. This unpleasant feature makes it extremely difficult both to obtain the metal itself and to manufacture alloys based on it.
The latter is possible only when using vacuum equipment. The most complex production process has turned a fairly common element into a very expensive one.
Bonding with other metals
Titanium occupies an intermediate position between the other two well-known structural materials - aluminum and iron, or rather, iron alloys. In many respects, the metal is superior to its "competitors":
- the mechanical strength of titanium is 2 times higher than that of iron, and 6 times higher than that of aluminum. In this case, the strength increases with decreasing temperature;
- corrosion resistance is much higher than that of iron and even aluminum;
- At normal temperatures, titanium is inert. However, when it rises to 250 C, it begins to absorb hydrogen, which affects the properties. In terms of chemical activity, it is inferior to magnesium, but, alas, it surpasses iron and aluminum;
- the metal conducts electricity much weaker: its electrical resistivity is 5 times higher than that of iron, 20 times higher than that of aluminum, and 10 times higher than that of magnesium;
- thermal conductivity is also much lower: 3 times less than iron 1, and 12 times less than aluminum. However, this property results in a very low coefficient of thermal expansion.
Pros and cons
In fact, titanium has many disadvantages. But the combination of strength and lightness is so in demand that neither the complex manufacturing method nor the need for exceptional purity stop metal consumers.
The undoubted advantages of the substance include:
- low density, which means very little weight;
- exceptional mechanical strength of both the titanium metal itself and its alloys. With increasing temperature, titanium alloys outperform all aluminum and magnesium alloys;
- the ratio of strength and density - specific strength, reaches 30–35, which is almost 2 times higher than that of the best structural steels;
- in air, titanium is coated with a thin layer of oxide, which provides excellent corrosion resistance.
Metal also has its drawbacks:
- Corrosion resistance and inertness only applies to non-active surface products. Titanium dust or shavings, for example, spontaneously ignite and burn at a temperature of 400 C;
- a very complex method of obtaining titanium metal provides a very high cost. The material is much more expensive than iron, or;
- the ability to absorb atmospheric gases with increasing temperature requires the use of vacuum equipment for melting and obtaining alloys, which also significantly increases the cost;
- titanium has poor antifriction properties - it does not work for friction;
- metal and its alloys are prone to hydrogen corrosion, which is difficult to prevent;
- titanium is difficult to machine. Welding it is also difficult due to the phase transition during heating.
Titanium sheet (photo)
Properties and characteristics
Strongly dependent on cleanliness. Reference data describe, of course, pure metal, but the characteristics of technical titanium can vary markedly.
- The density of the metal decreases when heated from 4.41 to 4.25 g/cm3. phase transition changes the density by only 0.15%.
- The melting point of the metal is 1668 C. The boiling point is 3227 C. Titanium is a refractory substance.
- On average, the tensile strength is 300–450 MPa, however, this figure can be increased to 2000 MPa by resorting to hardening and aging, as well as the introduction of additional elements.
- On the HB scale, the hardness is 103 and this is not the limit.
- The heat capacity of titanium is low - 0.523 kJ/(kg K).
- Specific electrical resistance - 42.1 10 -6 ohm cm.
- Titanium is a paramagnet. As the temperature decreases, its magnetic susceptibility decreases.
- Metal as a whole is characterized by ductility and malleability. However, these properties are strongly influenced by oxygen and nitrogen in the alloy. Both elements make the material brittle.
The substance is resistant to many acids, including nitric, sulfuric in low concentrations and almost all organic acids except formic. This quality ensures that titanium is in demand in the chemical, petrochemical, paper industry and so on.
Structure and composition
Titanium - although it is a transition metal, and its electrical resistivity is low, nevertheless, it is a metal and conducts electric current, which means an ordered structure. When heated to a certain temperature, the structure changes:
- up to 883 C, the α-phase is stable with a density of 4.55 g / cu. see It is distinguished by a dense hexagonal lattice. Oxygen dissolves in this phase with the formation of interstitial solutions and stabilizes the α-modification - pushes the temperature limit;
- above 883 C, the β-phase with a body-centered cubic lattice is stable. Its density is somewhat less - 4.22 g / cu. see. Hydrogen stabilizes this structure - when it is dissolved in titanium, interstitial solutions and hydrides are also formed.
This feature makes the work of the metallurgist very difficult. The solubility of hydrogen decreases sharply when titanium is cooled, and hydrogen hydride, the γ-phase, precipitates in the alloy.
It causes cold cracks during welding, so manufacturers have to work extra hard after melting the metal to clean it of hydrogen.
About where you can find and how to make titanium, we will tell below.
This video is dedicated to the description of titanium as a metal:
Production and mining
Titanium is very common, so that with ores containing metal, and in fairly large quantities, there are no difficulties. The raw materials are rutile, anatase and brookite - titanium dioxide in various modifications, ilmenite, pyrophanite - compounds with iron, and so on.
But it is complex and requires expensive equipment. The methods of obtaining are somewhat different, since the composition of the ore is different. For example, the scheme for obtaining metal from ilmenite ores looks like this:
- obtaining titanium slag - the rock is loaded into an electric arc furnace together with a reducing agent - anthracite, charcoal and heated to 1650 C. At the same time, iron is separated, which is used to obtain cast iron and titanium dioxide in the slag;
- slag is chlorinated in mine or salt chlorinators. The essence of the process is to convert solid dioxide into gaseous titanium tetrachloride;
- in resistance furnaces in special flasks, the metal is reduced with sodium or magnesium from chloride. As a result, a simple mass is obtained - a titanium sponge. This is technical titanium quite suitable for the manufacture of chemical equipment, for example;
- if a purer metal is required, they resort to refining - while the metal reacts with iodine in order to obtain gaseous iodide, and the latter, under the influence of temperature - 1300-1400 C, and electric current, decomposes, releasing pure titanium. An electric current is supplied through a titanium wire stretched in a retort, onto which a pure substance is deposited.
To obtain titanium ingots, the titanium sponge is melted down in a vacuum furnace to prevent hydrogen and nitrogen from dissolving.
The price of titanium per 1 kg is very high: depending on the degree of purity, the metal costs from $25 to $40 per 1 kg. On the other hand, the case of an acid-resistant stainless steel apparatus will cost 150 rubles. and will last no more than 6 months. Titanium will cost about 600 r, but is operated for 10 years. There are many titanium production facilities in Russia.
Areas of use
The influence of the degree of purification on the physical and mechanical properties forces us to consider it from this point of view. So, technical, that is, not the purest metal, has excellent corrosion resistance, lightness and strength, which determines its use:
- chemical industry– heat exchangers, pipes, casings, pump parts, fittings and so on. The material is indispensable in areas where acid resistance and strength are required;
- transport industry- the substance is used to make vehicles from trains to bicycles. In the first case, the metal provides a smaller mass of compounds, which makes traction more efficient, in the latter it gives lightness and strength, it is not for nothing that a titanium bicycle frame is considered the best;
- naval affairs- titanium is used to make heat exchangers, exhaust silencers for submarines, valves, propellers, and so on;
- in construction widely used - titanium - an excellent material for finishing facades and roofs. Along with strength, the alloy provides another advantage important for architecture - the ability to give products the most bizarre configuration, the ability to shape the alloy is unlimited.
The pure metal is also very resistant to high temperatures and retains its strength. The application is obvious:
- rocket and aircraft industry - sheathing is made from it. Engine parts, fasteners, chassis parts and so on;
- medicine - biological inertness and lightness makes titanium a much more promising material for prosthetics, up to heart valves;
- cryogenic technology - titanium is one of the few substances that, when the temperature drops, only become stronger and does not lose plasticity.
Titanium is a structural material of the highest strength with such lightness and ductility. These unique qualities provide him with more and more important role in the national economy.
The video below will tell you where to get titanium for a knife:
Titanium(lat. titanium), ti, a chemical element of group iv of Mendeleev's periodic system; atomic number 22, atomic mass 47.90; is silvery white in color light metals. Natural T. consists of a mixture of five stable isotopes: 46 ti (7.95%), 47 ti (7.75%), 48 ti (73.45%), 49 ti (5.51%), 50 ti (5 .34%). Artificial radioactive isotopes 45 ti are known (ti 1/2 = 3.09 h, 51 ti (ti 1/2 = 5.79 min) and etc.
History reference. T. in the form of dioxide was discovered by the English amateur mineralogist W. Gregor in 1791 in the magnetic ferruginous sands of the town of Menakan (England); in 1795, the German chemist M. G. Klaproth established that the mineral rutile is a natural oxide of the same metal, which he called "titanium" [in Greek mythology, titans are the children of Uranus (Heaven) and Gaia (Earth)]. It was not possible to isolate T. in its pure form for a long time; It was only in 1910 that the American scientist M. A. Hunter obtained metallic sodium by heating its chloride with sodium in a sealed steel bomb. the metal he obtained was ductile only at elevated temperatures and brittle at room temperature due to the high content of impurities. The opportunity to study the properties of pure titanium appeared only in 1925, when the Dutch scientists A. Van Arkel and J. de Boer obtained a high-purity metal plastic at low temperatures by the thermal dissociation of titanium iodide.
distribution in nature. T. is one of the common elements, its average content in the earth's crust (clarke) is 0.57% by weight (among structural metals, it ranks fourth in abundance, behind iron, aluminum, and magnesium). Most of all T. in the basic rocks of the so-called "basalt shell" (0.9%), less in the rocks of the "granite shell" (0.23%), and even less in ultrabasic rocks (0.03%), etc. rocks The minerals enriched in T. include pegmatites of basic rocks, alkaline rocks, syenites, and pegmatites associated with them. Sixty-seven T. minerals are known, mostly of igneous origin; the most important are rutile and ilmenite.
In the biosphere, T. is mostly dispersed. In sea water it contains 1 10 -7%; T. is a weak migrant.
physical properties. T. exists in the form of two allotropic modifications: below a temperature of 882.5 ° C, the a-form with a hexagonal close-packed lattice is stable ( a= 2.951 å, With= 4.679 å), and above this temperature - b-form with a cubic body-centered lattice a =£3.269 Impurities and dopants can significantly change the a/b transformation temperature.
Density a-form at 20 °C 4.505 g/cm 3 a at 870 °C 4.35 g/cm 3 b-forms at 900 °C 4.32 g/cm 3; atomic radius ti 1.46 å, ionic radii ti + 0.94 å, ti 2+ 0.78 å, ti 3+ 0.69 å, ti 4+ 0.64 å , t pl 1668±5°С, t kip 3227 °C; thermal conductivity in the range of 20-25 °С 22.065 Tue/(m? TO) ; temperature coefficient of linear expansion at 20 °C 8.5? 10 -6, in the range of 20-700 ° C 9.7? 10 -6; heat capacity 0.523 kJ/(kg? TO) ; electrical resistivity 42.1? 10-6 ohm? cm at 20 °C; temperature coefficient of electrical resistance 0.0035 at 20 °C; has superconductivity below 0.38 ± 0.01 K. T. paramagnetic, specific magnetic susceptibility (3.2 ± 0.4)? 10 -6 at 20°C. Tensile Strength 256 Mn/m 2 (25,6 kgf/mm 2) , elongation 72%, Brinell hardness less than 1000 Mn/m 2 (100 kgf/mm 2) . Modulus of normal elasticity 108000 Mn/m 2 (10800 kgf/mm 2) . Metal high degree cleanliness of forgings at normal temperature.
The technical grade used in industry contains impurities of oxygen, nitrogen, iron, silicon, and carbon, which increase its strength, reduce ductility, and affect the temperature of the polymorphic transformation, which occurs in the range of 865–920°C. For technical grades VT1-00 and VT1-0, the density is about 4.32 g/cm 3 , tensile strength 300- 550 Mn/m 2 (30-55 kgf/mm 2) , elongation not less than 25%, Brinell hardness 1150-1650 Mn/m 2 (115-165 kgf/mm 2) . The configuration of the outer electron shell of the atom ti 3 d 2 4 s 2 .
Chemical properties . Pure T. - reactive transition element, in compounds it has oxidation states + 4, less often +3 and +2. At ordinary temperatures and up to 500-550 ° C, it is corrosion resistant, which is explained by the presence of a thin but strong oxide film on its surface.
Significantly interacts with atmospheric oxygen at temperatures above 600 ° C with the formation of tio 2 . Thin titanium chips with insufficient lubrication can catch fire during machining. With sufficient oxygen concentration in environment and damage to the oxide film by impact or friction, it is possible to ignite the metal at room temperature and in relatively large pieces.
The oxide film does not protect the thermometer in the liquid state from further interaction with oxygen (unlike, for example, aluminum), and therefore its melting and welding must be carried out in a vacuum, in an atmosphere of a neutral gas, or under a flux. T. has the ability to absorb atmospheric gases and hydrogen, forming brittle alloys unsuitable for practical use; in the presence of an activated surface, hydrogen absorption occurs even at room temperature at a low rate, which increases significantly at 400 °C and above. The solubility of hydrogen in T. is reversible, and this gas can be removed almost completely by vacuum annealing. Nitrogen reacts with nitrogen at temperatures above 700°C to form nitrides of the tin type; in the form of a fine powder or wire, T. can burn in a nitrogen atmosphere. The rate of diffusion of nitrogen and oxygen in T. is much lower than that of hydrogen. The layer obtained as a result of interaction with these gases is characterized by increased hardness and brittleness and must be removed from the surface of titanium products by etching or machining. T. interacts vigorously with dry halogens , in relation to wet halogens it is stable, since moisture plays the role of an inhibitor.
The metal is stable in nitric acid of all concentrations (with the exception of red fuming acid, which causes corrosion cracking of the acid, and the reaction sometimes occurs with an explosion), in weak solutions of sulfuric acid (up to 5% by weight). Hydrochloric, hydrofluoric, concentrated sulfuric, as well as hot organic acids: oxalic, formic, and trichloroacetic acids react with T.
T. is corrosion resistant in atmospheric air, sea water and the sea atmosphere, in moist chlorine, chlorine water, hot and cold chloride solutions, in various technological solutions and reagents used in the chemical, oil, paper, and other industries, as well as in hydrometallurgy. T. forms metal-like compounds with C, B, se, and si, which are distinguished by their refractoriness and high hardness. tig carbide ( t pl 3140 °C) is obtained by heating a mixture of tio 2 with soot at 1900-2000 °C in a hydrogen atmosphere; tin nitride ( t pl 2950 ° C) - by heating the powder of T. in nitrogen at a temperature above 700 ° C. Silicides tisi 2 , ti 5 si 3 , tisi and borides tib, ti 2 b 5 , tib 2 are known. At temperatures between 400 and 600°C, T. absorbs hydrogen to form solid solutions and hydrides (tih, tih 2). When tio 2 is fused with alkalis, titanium acid salts of meta- and orthotitanates are formed (for example, na 2 tio 3 and na 4 tio 4), as well as polytitanates (for example, na 2 ti 2 o 5 and na 2 ti 3 o 7). Titanates include the most important minerals of tetanus, such as ilmenite fetio 3 and perovskite catio 3 . All titanates are slightly soluble in water. Titanium dioxide, titanic acids (precipitates), and titanates dissolve in sulfuric acid to form solutions containing tioso 4 titanyl sulfate. When the solutions are diluted and heated, h 2 tio 3 precipitates as a result of hydrolysis, from which T dioxide is obtained. When hydrogen peroxide is added to acidic solutions containing ti (iv) compounds, peroxide (supertitanic) acids of the composition h 4 tio 5 and h 4 tio are formed 8 and their corresponding salts; these compounds are colored yellow or orange-red (depending on the concentration of T.), which is used for the analytical determination of T.
Receipt. The most common method for obtaining metallic mercury is the magnesium-thermal method, that is, the reduction of sodium tetrachloride with metallic magnesium (less commonly, sodium):
ticl 4 + 2mg = ti + 2mgcl 2 .
In both cases, oxide ores of titanium—rutile, ilmenite, and others—serve as the initial raw material. In the case of ores of the ilmenite type, titanium is separated from iron in the form of slag by smelting in electric furnaces. Slag (just like rutile) is subjected to chlorination in the presence of carbon to form T. tetrachloride, which, after purification, enters a reduction reactor with a neutral atmosphere.
According to this process, steel is obtained in a spongy form and, after grinding, is remelted in vacuum arc furnaces into ingots with the introduction of alloying additives, if it is required to obtain an alloy. Magnesium thermal method allows you to create a large industrial production T. with a closed technological cycle, since the by-product formed during the reduction - magnesium chloride is sent to electrolysis to obtain magnesium and chlorine.
In a number of cases, it is advantageous to use the methods of powder metallurgy for the production of products from titanium and its alloys. To obtain particularly fine powders (for example, for radio electronics), it is possible to use the reduction of titanium dioxide with calcium hydride.
World production of metal t. developed very rapidly: about 2 t in 1948, 2100 t in 1953, 20,000 t in 1957; in 1975 it exceeded 50,000 t.
Application . T.'s main advantages over other structural metals are a combination of lightness, strength, and corrosion resistance. Titanium alloys in absolute, and even more so in specific strength (that is, strength related to density) surpass most alloys based on other metals (for example, iron or nickel) at temperatures from -250 to 550 ° C, and they are comparable in corrosion with noble metal alloys . However, T. began to be used as an independent structural material only in the 1950s. 20th century due to the great technical difficulties of its extraction from ores and processing (which is why T. was conditionally referred to rare metals ) . The main part of the technology is spent on the needs of aviation and rocket technology and marine shipbuilding. . Ferro-titanium alloys with iron, known as ferrotitanium (20-50% iron), serve as an alloying additive and deoxidizer in the metallurgy of high-quality steels and special alloys.
Technical technology is used to manufacture tanks, chemical reactors, pipelines, fittings, pumps, and other products that operate in aggressive environments, such as in chemical engineering. In the hydrometallurgy of non-ferrous metals, equipment from T is used. It serves to cover steel products. . The use of thermodynamics in many cases yields a great technical and economic effect, not only due to an increase in the service life of equipment, but also due to the possibility of intensifying processes (as, for example, in nickel hydrometallurgy). The biological harmlessness of T. makes it an excellent material for the manufacture of equipment for the food industry and in reconstructive surgery. Under conditions of deep cold, the strength of T. increases while maintaining good plasticity, which makes it possible to use it as a structural material for cryogenic technology. T. lends itself well to polishing, color anodizing, and other methods of surface finishing, and therefore is used to make various artistic products, including monumental sculpture. An example is the monument in Moscow, erected in honor of the launch of the first artificial Earth satellite. Of the titanium compounds, the oxides of titanium, the halides of titanium, and also the silicides of titanium, which are used in high-temperature technology, are of practical importance; T. borides and their alloys, which are used as moderators in nuclear power plants due to their infusibility and large neutron capture cross section. Carbide T., which has a high hardness, is part of the tool hard alloys used for the manufacture of cutting tools and as an abrasive material.
Titanium dioxide and barium titanate serve as the basis titanium ceramics, and barium titanate is the most important ferroelectric.
S. G. Glazunov.
Titanium in the body. T. is constantly present in the tissues of plants and animals. In terrestrial plants, its concentration is about 10 -4% , in marine - from 1.2? 10 -3 to 8? 10 -2% , in the tissues of terrestrial animals - less than 2? 10 -4% , marine - from 2? 10 -4 to 2 ? 10 -2%. Accumulates in vertebrates mainly in horny formations, spleen, adrenal glands, thyroid gland, placenta; poorly absorbed from the gastrointestinal tract. In humans, the daily intake of T. with food and water is 0.85 mg; excreted in urine and feces (0.33 and 0.52 mg respectively). Relatively low toxicity.
Lit.: Glazunov S. G., Moiseev V. N., Structural titanium alloys, M., 1974; Metallurgy of titanium, M., 1968; Goroshchenko Ya. G., Chemistry of titanium, [ch. 1-2], K., 1970-72; zwicker u., titan und titanlegierungen, b., 1974; Bowen h. i. m., trace elements in biochemistry, l.- n. y., 1966.
