What Is Titanium?
Titanium is a metal chemical element, chemical symbol Ti, atomic number 22, located in the fourth period, IVB group in the periodic table of chemical elements. It is a silver-white transition metal characterized by light weight, high strength, metallic luster, and resistance to wet chlorine corrosion. But titanium cannot be used in dry chlorine. Even dry chlorine at a temperature below 0°C will undergo a violent chemical reaction to form titanium tetrachloride, which will then decompose to form titanium dichloride, or even burn. Only when the water content in the chlorine gas is higher than 0.5%, the titanium can maintain reliable stability in it.
Titanium is considered a rare metal because it is scattered in nature and difficult to extract. But it is relatively rich, ranking tenth among all elements. Titanium ore mainly includes ilmenite and rutile, which are widely distributed in the crust and lithosphere. Titanium is also present in almost all living things, rocks, water bodies and soil. The Kroll method or Hunter method is required to extract titanium from the main ore. The most common compound of titanium is titanium dioxide, which can be used to make white pigments. Other compounds also include titanium tetrachloride (TiCl4) (used as a catalyst and used to make smoke screens as air cover) and titanium trichloride (TiCl3) (used to catalyze the production of polypropylene).
The Development History Of Titanium
The discovery of titanium
- Gregor (Reverend William Gregor, 1762—1817): In 1791, titanium was discovered in Cornwall, England in the form of titanium-containing minerals. The discoverer was the English amateur mineralogist Gregor (Reverend William Gregor). ), who was working as a pastor in charge of the Diocese of Creed in Cornwall. He found some black sand by the creek in the neighbouring Manaccan parish. Later, he discovered that the sand would be attracted by magnets. He realized that this mineral (ilmenite) contains a new element. . After analysis, it was found that there were two metal oxides in the sand: iron oxide (the reason the sand is attracted by the magnet) and a white metal oxide that he could not identify. Realizing that this unidentified oxide contains an undiscovered metal, Gregor published the discovery to the Royal Geological Society of Cornwall and the German Annals of Chemistry. At about the same time, Franz-Joseph Müller von Reichenstein produced a similar substance, but could not identify it.
- Klaproth  (Martin Heinrich Klaproth, 1743-1817): In 1795, the German chemist Klaproth also discovered this oxide when analyzing red rutile produced in Hungary. He advocated adopting the method of naming uranium (discovered by Kraprot in 1789), citing the name of the Titanic tribe in Greek mythology, “Titanic”, to name this new element “Titanium”. The Chinese name is named Titanium according to its transliteration. When he heard of Gregor’s earlier discovery, Klaprott obtained some samples of the Manacán mineral and confirmed that it contained titanium.
- Hunter (Matthew A. Hunter): The titanium discovered by Gregor and Kraprot at the time was powdered titanium dioxide, not metallic titanium. Because the oxide of titanium is extremely stable, and metal titanium can directly and fiercely combine with oxygen, nitrogen, hydrogen, carbon, etc., elemental titanium is difficult to prepare. It was not until 1910 that the American chemist Hunter used sodium to reduce TiCl4 to produce titanium with a purity of 99.9%.
In 1940, Luxembourg scientist W.J.Kroll used magnesium to reduce TiCl4 to obtain pure titanium. Since then, the magnesium reduction method (also known as the Kraul method) and the sodium reduction method (also known as the Hunter method) have become industrial methods for producing sponge titanium. The United States produced 2 tons of sponge titanium using the magnesium reduction method in 1948, and since then began the industrial production of titanium.
In 1947, people began to smelt titanium in factories. That year, the output was only 2 tons. Production surged to 20,000 tons in 1955. In 1972, the annual output reached 200,000 tons. The yield strength of titanium is higher than that of steel, and its weight is almost half of the same volume of steel. Although titanium is slightly heavier than aluminum, its yield strength is twice that of aluminum. The specific strength of titanium is higher than that of aluminum and steel, and the specific modulus is very close to that of aluminum and steel. In space rockets and missiles, large amounts of titanium are used instead of steel. According to statistics, the world’s annual titanium used for space navigation has reached more than 1,000 tons. Very fine titanium powder is also a good fuel for rockets, so titanium is known as cosmic metal and space metal.
Titanium easily reacts with air at high temperatures, but its melting point is as high as 1668°C. At normal temperature, titanium is not afraid of corrosion by aqua regia and dilute nitric acid, but it is not resistant to corrosion by sulfuric acid and 7% hydrochloric acid with a concentration of more than 5%. Titanium is not afraid of seawater at room temperature. Someone once sunk a piece of titanium to the bottom of the sea, and took it up five years later. There were many small animals and seabed plants stuck on it, but there was no rust at all, and it was still shiny.
People began to use titanium to make submarines-titanium submarines. Because titanium is very strong and can withstand high pressure, this submarine can sail in deep seas as deep as 4500 meters.
The Content Distribution Of Titanium
The ten-kilometer-thick stratum on the earth’s surface contains six thousandths of titanium, 61 times more than copper, and ranks tenth in the crust (ranking elements in the crust: oxygen, silicon, aluminum, iron, calcium, sodium, Potassium, magnesium, hydrogen, titanium), just grab a handful of soil from the ground, which contains a few thousandths of titanium. Titanium ore with reserves of more than 10 million tons in the world is not rare.
There are hundreds of millions of tons of sand and gravel on the earth. Titanium and zirconium, two minerals heavier than sand and gravel, are mixed in the sand and gravel. After the seawater has been washed day and night for millions of years, the heavier ilmenite Crushing with the zircon placer, on the long coast, a piece of titanium ore layer and zirconium ore layer are formed. This mineral layer is a black sand, usually a few centimeters to tens of centimeters thick. Titanium is not ferromagnetic, and nuclear submarines built with titanium do not have to worry about attacks by magnetic mines.
The Parameters Of Titanium
- CAS No.: 7440-32-6
- EINECS number: 241-336-9
- The content of elements in seawater: 0.00048 ppm
- The content of elements in the sun: 4 ppm
- Element type: transition metal
- Number of protons in the nucleus: 22
- Number of out-of-core electrons: 22
- Number of nuclear charges: 22
- Peripheral electronic layer arrangement: 3d2 4s2
- Electronic layer: K-L-M-N
- Proton mass: 3.6806E-26
- Relative mass of proton: 22.154
- Atomic volume: 10.64 cm3/mol
- Content in the crust: 5600 ppm
- The following is the added content:
- Oxidation state: +4 (mainly), -1, 0, +2, +3
- Owning cycle: the fourth cycle
- Number of families: Ⅳ B
- Molar mass: 48 g/mol
- Hydride: TiH4
- The highest valence oxide chemical formula: TiO2
- Density: 4.54 g/cm3
- Melting point: 1660.0°C
- Boiling point: 3287.0℃
- Ionization energy (kJ/mol)
- M-M+ 658
- M+-M2+ 1310
- M2+-M3+ 2652
- M3+-M4+ 4175
- M4+-M5+ 9573
- M5+-M6+ 11516
- M6+-M7+ 13590
- M7+-M8+ 16260
- M8+-M9+ 18640
- M9+-M10+ 20830
- Out-of-nuclear electronic layout: 2,8,10,2
- Crystal structure: The unit cell is a hexagonal unit cell.
- Cell parameters:
- a = 295.08 pm
- b = 295.08 pm
- c = 468.55 pm
- α = 90°
- β = 90°
- γ = 120°
- Mohs hardness: 6
- Sound propagation speed in it: 5090 m/s
- Color and state: silver-gray metal
- Atomic radius: 2
- Discovered by: Gregor. Discovered: 1791
- There are 13 known isotopes of titanium, including titanium-41 to titanium-53. Among them, there are five stable isotopes of titanium: titanium-46, titanium-47, titanium-48, titanium-49, and titanium-50. The remaining isotopes are all radioactive.
The Physical Properties Of Titanium
Titanium has metallic luster and ductility. The density is 4.5g/cm3. The melting point is 1668°C. The boiling point is 3287°C. Common valences +2, +3 and +4. The ionization energy is 6.82 eV. The main characteristics of titanium are low density, high mechanical strength, and easy processing. The plasticity of titanium mainly depends on purity. The purer the titanium, the greater the plasticity. It has good corrosion resistance and is not affected by the atmosphere and sea water. At room temperature, it will not be corroded by hydrochloric acid below 7%, sulfuric acid below 5%, nitric acid, aqua regia or dilute alkali solution; only hydrofluoric acid, concentrated hydrochloric acid, concentrated sulfuric acid, etc. can act on it.
Titanium is an important alloying element in steel and alloys. The density of titanium is 4.506-4.516 g/cc (20°C), which is higher than aluminum but lower than iron, copper, and nickel. But the specific strength is at the top of the metal.  The melting point is 1668°C, the latent heat of fusion is 3.7-5.0 kcal/gram atom, the boiling point is 3260±20°C, the latent heat of vaporization is 102.5-112.5 kcal/gram atom, the critical temperature is 4350°C, and the critical pressure is 1130 atmospheres. Titanium has poor thermal and electrical conductivity, which is similar to or slightly lower than that of stainless steel. Titanium has superconductivity. The superconducting critical temperature of pure titanium is 0.38-0.4K. At 25°C, the heat capacity of titanium is 0.126 cal/gram atom·degree, the enthalpy is 1149 cal/gram atom, and the entropy is 7.33 cal/gram atom·degree. Titanium is a paramagnetic substance with a magnetic permeability of 1.00004.
Titanium has plasticity. The elongation of high-purity titanium can reach 50-60%, and the reduction of area can reach 70-80%, but the shrinkage strength is low (that is, the strength generated during shrinkage). The presence of impurities in titanium has a great impact on its mechanical properties, especially interstitial impurities (oxygen, nitrogen, carbon) can greatly increase the strength of titanium and significantly reduce its plasticity. The good mechanical properties of titanium as a structural material are achieved through strict control of the appropriate impurity content and the addition of alloying elements.
The Chemical Properties Of Titanium
Titanium can react with many elements and compounds at higher temperatures. Various elements can be divided into four categories according to their different reactions with titanium:
- The first category: halogen and oxygen group elements form covalent bond and ionic bond compounds with titanium;
- The second category: transition elements, hydrogen, beryllium, boron, carbon and nitrogen elements form intermetallic compounds and finite solid solutions with titanium;
- The third category: zirconium, hafnium, vanadium, chromium, scandium and titanium form an infinite solid solution;
- The fourth category: inert gases, alkali metals, alkaline earth metals, rare earth elements (except scandium), actinium, thorium, etc. do not react or basically do not react with titanium.
It reacts with the compound HF and fluoride hydrogen fluoride gas to produce TiF4 when heated, and the reaction formula is
The non-aqueous hydrogen fluoride liquid can form a dense titanium tetrafluoride film on the titanium surface, which can prevent HF from immersing into the titanium. Hydrofluoric acid is the strongest solvent for titanium. Even hydrofluoric acid with a concentration of 1% can react violently with titanium:
Anhydrous fluoride and its aqueous solution do not react with titanium at low temperatures, only the fluoride that melts at high temperatures reacts significantly with titanium. HCl and chloride hydrogen chloride gas can corrode metal titanium, and dry hydrogen chloride reacts with titanium to form TiCl4 at >300°C:
Hydrochloric acid with a concentration of <5% will not react with titanium at room temperature, and 20% of hydrochloric acid will react with titanium at room temperature to produce purple TiCl3:
When the temperature is high, even dilute hydrochloric acid will corrode titanium. Various anhydrous chlorides, such as magnesium, manganese, iron, nickel, copper, zinc, mercury, tin, calcium, sodium, barium and NH4+ ions and their aqueous solutions, do not react with titanium. Titanium is in these chlorides Has good stability. Sulfuric acid and titanium hydrogen sulfide have obvious reactions with 5% sulfuric acid. At room temperature, about 40% sulfuric acid has the fastest corrosion rate on titanium. When the concentration is greater than 40% and reaches 60%, the corrosion rate becomes slower, 80% Reached the fastest. Heated dilute acid or 50% concentrated sulfuric acid can react with titanium to form titanium sulfate:
The heated concentrated sulfuric acid can be reduced by titanium to generate SO2:
Titanium reacts with hydrogen sulfide at room temperature to form a protective film on its surface, which can prevent further reaction of hydrogen sulfide with titanium. But at high temperatures, hydrogen sulfide reacts with titanium to produce hydrogen:
The powdered titanium reacts with hydrogen sulfide to form titanium sulfide at 600°C. The reaction product is mainly TiS at 900°C and Ti2S3 at 1200°C. The dense and smooth surface of nitric acid and aqua regia titanium has good stability to nitric acid. This is because nitric acid can quickly form a strong oxide film on the surface of titanium, but the surface is rough, especially sponge titanium or powder titanium. Second, hot dilute nitric acid reacts:
Concentrated nitric acid above 70℃ can also react with titanium:
At room temperature, titanium does not react with aqua regia. When the temperature is high, titanium can react with aqua regia to generate TiCl2.
In summary, the properties of titanium have an extremely close relationship with temperature, its existence form, and purity. The dense metallic titanium is quite stable in nature, but powdered titanium can cause spontaneous combustion in the air. The presence of impurities in titanium significantly affects the physical, chemical, mechanical, and corrosion resistance of titanium. Especially some interstitial impurities, they can distort the titanium lattice and affect the various properties of titanium. The chemical activity of titanium is very small at room temperature, and it can react with a few substances such as hydrofluoric acid, but the activity of titanium increases rapidly when the temperature increases, especially at high temperatures, titanium can react violently with many substances. The smelting process of titanium is generally carried out at a high temperature above 800 ℃, so it must be operated in a vacuum or under the protection of an inert atmosphere. The physical properties of titanium metal titanium (Ti), gray metal. The atomic number is 22 and the relative atomic mass is 47.87. The arrangement of extranuclear electrons in the sublayer is 1s2 2s2 2p6 3s2 3p6 3d2 4s2. Metal mobility is between magnesium and aluminum, and it is not stable at room temperature. Therefore, it only exists in a chemical state in nature. Common titanium compounds include ilmenite (FeTiO3) and rutile (TiO2). The content of titanium in the earth’s crust is relatively high, ranking ninth, reaching 5600ppm, which is converted into a percentage of 0.56%. The density of pure titanium is 4.54×103 kg/m3, the molar volume is 10.54 cm3/mol, the hardness is poor, and the Mohs hardness is only about 4, so it has good ductility. Titanium has good thermal stability, with a melting point of 1668°C and a boiling point of 3287°C. The chemical properties of titanium metal The reduction ability of titanium metal is extremely strong in high-temperature environments. It can combine with oxygen, carbon, nitrogen and many other elements, and it can also extract oxygen from some metal oxides (such as aluminum oxide). Titanium combines with oxygen at room temperature to form an extremely thin and dense oxide film. This oxide film does not react with nitric acid, dilute sulfuric acid, dilute hydrochloric acid, and the king of acids-aqua regia at room temperature. It reacts with hydrofluoric acid, concentrated hydrochloric acid, and concentrated sulfuric acid.
Titanium is corrosion resistant, so it is often used in the chemical industry. In the past, stainless steel was used for the parts containing hot nitric acid in chemical reactors. Stainless steel is also afraid of the strong corrosive agent-hot nitric acid. This kind of parts must be replaced every six months. Titanium is used to make these parts, although the cost is more expensive than stainless steel parts, but it can be used continuously for five years, but it is much more cost-effective to calculate.
In electrochemistry, titanium is a one-way valve type metal with very negative potential, and it is usually impossible to use titanium as an anode for decomposition.
The biggest disadvantage of titanium is that it is difficult to extract. The main reason is that titanium has a strong ability to combine with oxygen, carbon, nitrogen and many other elements at high temperatures. Therefore, no matter when smelting or casting, people are careful to prevent these elements from “invading” titanium. When smelting titanium, air and water are of course strictly forbidden. Even the alumina crucible commonly used in metallurgy is also forbidden to use, because titanium will take oxygen from the alumina. People use magnesium and titanium tetrachloride to interact in an inert gas-helium or argon to refine titanium.
People take advantage of the extremely strong chemical ability of titanium at high temperatures. During steelmaking, nitrogen is easily dissolved in molten steel. When the steel ingot is cooled, bubbles are formed in the steel ingot, which affects the quality of steel. Therefore, steel workers add titanium metal to the molten steel to combine with nitriding and turn it into slag—titanium nitride, which floats on the surface of the molten steel, so that the steel ingot is relatively pure.
When a supersonic aircraft is flying, the temperature of its wings can reach 500°C. If the wing is made of relatively heat-resistant aluminum alloy, one to two or three hundred degrees will be overwhelming. There must be a light, tough, and high-temperature resistant material to replace the aluminum alloy. Titanium can meet these requirements. Titanium can withstand the test of more than one hundred degrees below zero. At this low temperature, titanium still has good toughness without being brittle.
The powerful absorption of titanium and zirconium on air can remove the air and create a vacuum. For example, a vacuum pump made of titanium can pump air to only one part of a ten trillion.
The oxide of titanium is titanium dioxide, natural TiO2 is rutile, and pure TiO2 is a white powder. It is the best white pigment, commonly known as titanium white, which is white when cold and light yellow when hot. In the past, the main purpose of mining titanium ore was to obtain titanium dioxide. Titanium dioxide has strong adhesion and is not easy to undergo chemical changes. It is always white and is an excellent white paint. It has high refractive index, strong coloring, large hiding power and stable chemical properties. Other white paints, such as zinc white ZnO and lead white 2PbCO3·Pb(OH)2, do not have these excellent properties of titanium white. Especially valuable is that titanium dioxide is non-toxic. It has a high melting point and is used to make refractory glass , glaze, enamel, clay, high temperature resistant laboratory utensils, etc.
Titanium dioxide is the whitest thing in the world. 1 gram of titanium dioxide can paint an area of more than 450 square centimeters white. It is 5 times whiter than the commonly used white pigment-Lithopone, so it is the best pigment for white paint. Titanium dioxide used as a pigment in the world can reach hundreds of thousands of tons a year. Titanium dioxide can be added to paper to make the paper white and opaque. The effect is 10 times greater than other substances. Therefore, it is necessary to add titanium dioxide to banknote paper and art paper. In addition, in order to lighten the color of the plastic and soften the luster of the rayon, titanium dioxide is sometimes added. In the rubber industry, titanium dioxide is also used as a filler for white rubber.
Titanium tetrachloride is very interesting. Under normal conditions, it is a colorless liquid (melting point: -25°C, boiling point: 136.4°C). It has a pungent odor. It will emit white smoke in moist air—it is hydrolyzed and becomes White hydrogel of titanium dioxide. In water, it is strongly hydrolyzed to metatitanic acid H2TiO3. In the military, people use the weird temper of titanium tetrachloride as an artificial aerosol. Especially in the ocean, there is a lot of water vapor, and when titanium tetrachloride is placed, the thick smoke looks like a white Great Wall, blocking the enemy’s sight. In agriculture, people use titanium tetrafluoride to prevent frost.
TiCl3 is a purple crystal, and its aqueous solution can be used as a reducing agent. Ti3+ has stronger reducibility than Sn2+ .
Barium titanate crystal has the characteristic: when it changes shape under pressure, it will generate electric current, and it will change shape when it is energized. Therefore, when people put barium titanate in ultrasonic waves, it generates electric current when it is pressed, and the strength of ultrasonic waves can be measured by the magnitude of the electric current generated by it. On the contrary, by passing high-frequency current through it, ultrasonic waves can be generated. Barium titanate is used in almost all ultrasonic instruments. In addition, barium titanate has many uses. For example: a railway worker puts it under the rails to measure the pressure when a train passes; a doctor uses it to make a pulse recorder. The underwater detector made of barium titanate is a sharp underwater eye. It can not only see the fish, but also the reefs, icebergs and enemy submarines under the water.
When smelting titanium, it has to go through complicated steps. Turn ilmenite into titanium tetrachloride, put it in a sealed stainless steel tank, and fill it with argon to make them react with metallic magnesium to obtain “sponge titanium”. This porous “sponge titanium” cannot be used directly, and it must be melted into a liquid in an electric furnace before it can be cast into a titanium ingot. But it’s not easy to make this kind of electric furnace! Except that the air in the electric furnace must be cleaned, what’s more troublesome is that there is almost no crucible containing liquid titanium, because general refractory materials contain oxides, and the oxygen in it will be taken away by the liquid titanium. Later, people finally invented a “water-cooled copper crucible” electric furnace. Only part of the central area of this electric furnace is very hot, and the rest are cold. After the titanium is melted in the electric furnace, it flows to the wall of the copper crucible cooled with water and immediately condenses into titanium ingots. This method has been able to produce several tons of titanium blocks, but its cost can be imagined.
The Classification Of Titanium
Industrial pure titanium: The impurity content of industrial pure titanium is more than that of chemical pure titanium, so its strength and hardness are slightly higher. Its mechanical and chemical properties are similar to those of stainless steel. Compared with titanium alloy, pure titanium has better strength and has better oxidation resistance. It is better than austenitic stainless steel, but has poor heat resistance. TA1, TA2, and TA3 increase in impurity content, mechanical strength and hardness increase in order, but plastic toughness decreases in order.
β-type titanium: β-type titanium alloy can be strengthened by heat treatment, with high alloy strength, good weldability and pressure workability, but its performance is unstable and the melting process is complicated.
- A, β titanium plate: 0.5-4.0mm
- B. Glasses plate (pure titanium): 0.8-8.0mm
- C. Standard plate (pure titanium): 1 x 2m Thickness: 0.5-20mm
- D. Plate for electroplating and other industries (pure titanium): 0.1-50mm
Uses: electronics, chemicals, watches, glasses, jewelry, sporting goods, mechanical equipment, electroplating equipment, environmental protection equipment, golf and precision processing industries.
Titanium tube specifications: φ6-φ120mm wall thickness: 0.3-3.0mm
Titanium tube uses: environmental protection equipment, cooling pipes, titanium heating pipes, electroplating equipment, rings and various precision electrical appliances pipes and other industries.
- A, β titanium wire specifications: φ0.8-φ6.0mm
- B. Specification of titanium wire for glasses: φ1.0-φ6.0mm dedicated titanium wire
- C. Titanium wire specifications: φ0.2-φ8.0mm for hangers
Titanium wire use: military industry, medical, sporting goods, glasses, earrings, headwear, electroplating hangers, welding wire and other industries.
- A. Square bar specifications: square bar: 8-12mm
- B. Polished round bar: φ4-φ60mm
- C. Wool rod, black leather rod: φ6-φ120mm
Titanium rod use: mainly used in mechanical equipment, electroplating equipment, medical, various precision parts and other industries.
- Reactor: Due to the different production processes and operating conditions of users, the jacket heating types are divided into electric heating rod heating, steam heating, and heat transfer oil circulating heating; shaft seals are divided into packing seals and mechanical seals; stirring types include anchor, Paddle type, pot wheel type, push type or frame type. The number of openings, specifications or other requirements can be designed and manufactured according to user requirements.
- Condenser: tube condenser, according to the material is divided into composite titanium tube and tube condenser, titanium tube and tube condenser and carbon steel and titanium mixed tube and tube condenser, according to the form is divided into fixed tube plate type, floating head type, U-tube heat exchangers are divided into single-tube pass, double-tube pass and multi-tube pass according to their structure. The heat transfer area is 0.5-500m2, which can be customized according to different needs of users.
- Tank: The fermentation tank designed by our factory is a standard tank type. When the nominal volume of this tank is below 6m3, the tank adopts a jacket type. The cooling or heating of the fermentation gas is completed by the jacket. When the nominal volume is more than 6m3, the cooling of the fermentation gas is borne by the vertical piping, and we have made improvements in the connection of the piping in the tank. This is mainly to avoid opening more holes on the tank body and opening a dead angle. This continuous method has achieved satisfactory results in actual use. Fermentation equipment tank types can be divided into two categories: one is the cone type for anaerobic fermentation (such as alcohol fermentation), and the other is the tank type for gas fermentation (such as standard type, Wu type, self-priming type, etc.). This type of equipment is most commonly used in standard tank types. The drawings and materials of the fermentation tank series designed by our factory belong to the standard tank type. When designing fermentation equipment of various specifications, the design structure should be tight, with sufficient strength and service life, and the internal accessories of the equipment should be small, and the surface should be smooth. It should be noted that there should be good gas-jujube-steam contact and steam-stabbing solid mixing performance. The material is transferred and the gas exchange is carried out effectively. There is enough heat exchange area to ensure that the fermentation can be carried out at the most suitable temperature. Pay attention to the sealing performance of the equipment to ensure the sterilization operation.
- Cooler: main purpose: mainly suitable for the concentration of liquid materials in the pharmaceutical, food, chemical and other industrial sectors, and it can also recover alcohol and simple reflux extraction. Structure: This equipment mainly consists of six parts including a concentration tank, a first condenser, a vapor-liquid separator, a second condenser, a cooler, and a liquid receiving barrel, all of which are made of titanium. The thickening tank is a jacket structure, the condenser is a tube type, and the cooler is a coil type.
Ten Properties Of Titanium
1.Low density, high specific strength
The density of titanium metal is 4.51g/cm3, which is higher than aluminum and lower than steel, copper, and nickel, but its specific strength is at the top of the metal.
Titanium is a very active metal, its equilibrium potential is very low, and the thermodynamic corrosion tendency in the medium is high. But in fact, titanium is very stable in many media. For example, titanium is corrosion-resistant in oxidizing, neutral and weakly reducing media. This is because titanium and oxygen have a great affinity. In the air or in an oxygen-containing medium, a dense, strong adhesion and inert oxide film is formed on the surface of titanium, which protects the titanium matrix from corrosion. Even due to mechanical wear, it will quickly heal itself or regenerate. This shows that titanium is a metal with a strong tendency to passivation. The titanium oxide film always maintains this characteristic when the medium temperature is below 315℃.
In order to improve the corrosion resistance of titanium, surface treatment technologies such as oxidation, electroplating, plasma spraying, ion nitriding, ion implantation and laser treatment have been developed to enhance the protection of the titanium oxide film and obtain the desired corrosion resistance. effect. In response to the needs of metal materials in the production of sulfuric acid, hydrochloric acid, methylamine solution, high-temperature wet chlorine and high-temperature chloride, a series of corrosion-resistant titanium alloys such as titanium-molybdenum, titanium-palladium, and titanium-molybdenum-nickel have been developed. Titanium castings are made of titanium-32 molybdenum alloy, titanium-0.3 molybdenum-0.8 nickel alloy is used in environments where crevice corrosion or pitting corrosion is common, or titanium-0.2 palladium alloy is used locally in titanium equipment, and they are all well used. effect.
3.Good heat resistance
The new titanium alloy can be used for a long time at a temperature of 600°C or higher.
4.Good low temperature resistance
Low temperature titanium alloy represented by titanium alloy TA7 (Ti-5Al-2.5Sn), TC4 (Ti-6Al-4V) and Ti-2.5Zr-1.5Mo, etc., whose strength increases with the decrease of temperature, but does not change plasticity. Big. It maintains good ductility and toughness at low temperatures of -196-253°C, avoids cold brittleness of metals, and is an ideal material for cryogenic containers, storage boxes and other equipment.
5.Strong resistance to damping
After metal titanium is subjected to mechanical vibration and electrical vibration, its vibration decay time is the longest compared with steel and copper metal. This performance of titanium can be used as a tuning fork, medical ultrasonic pulverizer vibrating element and high-end acoustic speaker vibrating film, etc.
Titanium is a non-magnetic metal and will not be magnetized in a large magnetic field. It is non-toxic and has good compatibility with human tissues and blood, so it is adopted by the medical profession.
7.The tensile strength is close to its yield strength
This property of titanium shows that its yield ratio (tensile strength/yield strength) is high, which means that the plastic deformation of metal titanium material is poor during forming. Due to the large ratio of the yield limit of titanium to the modulus of elasticity, the resilience of titanium during molding is large.
8.Good heat transfer performance
Although the thermal conductivity of metallic titanium is lower than that of carbon steel and copper, due to the excellent corrosion resistance of titanium, the wall thickness can be greatly reduced, and the heat exchange between the surface and the steam is dropwise condensation, which reduces the heat group. Without scaling, the thermal resistance can be reduced, and the heat transfer performance of titanium can be significantly improved.
9.Low modulus of elasticity
The elastic modulus of titanium is 106.4GPa at room temperature, which is 57% of steel.
Titanium is a chemically very active metal, which can react with many elements and compounds at high temperatures. Titanium getter mainly refers to the reaction with carbon, hydrogen, nitrogen, and oxygen at high temperatures.