Necmettin Erbakan Üniversitesi
Mühendislik ve Mimarlık Fakültesi
Metalurji ve Malzeme Mühendisliği Bölümü
İleri Teknoloji Seramikler Dersi
Emre AVCI
Aralık 2020
Borürler, Titanyum Diborür, Lantanyum Hekzaborür
,borides ,borür ,titanyum diborür ,lantanyum hekzaborür ,titanium diboride ,tanhanum hexaboride ,titanyum diborür uygulamaları ,lantanyum hekzaborür kullanım alanları ,borürlerin üretimi ,titanyum diborür üretimi
Refractories are heat-resistant materials used to line furnaces and withstand high temperatures. Furnaces are used to melt metals and change their shape and properties. Refractories must withstand high heat, molten materials, gases, and stresses. Their key properties include melting point, density, porosity, strength, and thermal conductivity. Common refractory types include fireclay, high alumina, silica, magnesite, chromite, and zirconia. The right refractory must match the furnace type, materials, temperatures, stresses, and chemical compatibility. Proper refractory selection is crucial for furnace performance and longevity.
Potentiostatic polarization curve of active-passive metal (Fe) & Flade potent...Saad Bin Hasan
This document discusses corrosion and passivity of metals, specifically:
1) It defines passivity as the formation of a thin surface film under oxidizing conditions that provides corrosion resistance to some metals and alloys.
2) It describes potentiostatic polarization as a technique to control metal polarization in electrolytes to observe corrosion behaviors.
3) It lists applications such as corrosion product analysis, alloy selection, and localized corrosion analysis.
4) It discusses concepts related to passivity including passive current density, primary passivation potential, and critical current density.
1. Corrosion is an electrochemical process involving oxidation and reduction reactions. It requires an anode, cathode, electrolyte, and an electrically conducting path.
2. At the anode, iron oxidizes to ferrous ions which then react with hydroxyl ions from the cathode to form iron hydroxide and iron oxide. The products occupy more volume than the original steel causing stresses in the concrete.
3. Chlorides from deicing salts or seawater can destroy the protective oxide layer and accelerate corrosion. Carbonation reduces concrete's alkalinity allowing the protective layer to break down.
This document provides information on calcium carbide, including its properties, manufacturing process, uses, packaging and international standards. Some key points:
- Calcium carbide is produced through heating limestone and coke to 2200-2500°C in an electric furnace. It reacts with water to produce acetylene gas.
- Its main uses are in producing acetylene for welding/cutting and calcium cyanamide as a fertilizer. It also acts as a dehydrating/reducing agent.
- The BIS specification outlines purity levels and gas yield requirements for different grades of calcium carbide. International standards also provide size classifications.
- Calcium carbide is packed in moisture
The document summarizes extraction and uses of magnesium. It describes common magnesium minerals like dolomite and magnesite. It discusses challenges in extracting magnesium through pyrometallurgical and electrometallurgical processes. The Pidgeon and Magnetotherm processes are described for pyrometallurgical extraction. The Dow process extracts magnesium from seawater through precipitation and electrolysis. Magnesium has non-structural uses like alloying, deoxidation, and cathodic protection. Structural uses include aircraft and transportation applications due to magnesium's high strength to weight ratio.
Tungsten is a transition metal that was discovered in Spain in the 1780s. It is a hard, dense metal with a high melting point that gives it important applications. Tungsten is commonly used in incandescent light bulb filaments, electronics, and to make carbides for drill bits and cutting tools due to its properties including density, hardness, and high melting point. The major deposits of tungsten are located in China.
Refractories are heat-resistant materials used to line furnaces and withstand high temperatures. Furnaces are used to melt metals and change their shape and properties. Refractories must withstand high heat, molten materials, gases, and stresses. Their key properties include melting point, density, porosity, strength, and thermal conductivity. Common refractory types include fireclay, high alumina, silica, magnesite, chromite, and zirconia. The right refractory must match the furnace type, materials, temperatures, stresses, and chemical compatibility. Proper refractory selection is crucial for furnace performance and longevity.
Potentiostatic polarization curve of active-passive metal (Fe) & Flade potent...Saad Bin Hasan
This document discusses corrosion and passivity of metals, specifically:
1) It defines passivity as the formation of a thin surface film under oxidizing conditions that provides corrosion resistance to some metals and alloys.
2) It describes potentiostatic polarization as a technique to control metal polarization in electrolytes to observe corrosion behaviors.
3) It lists applications such as corrosion product analysis, alloy selection, and localized corrosion analysis.
4) It discusses concepts related to passivity including passive current density, primary passivation potential, and critical current density.
1. Corrosion is an electrochemical process involving oxidation and reduction reactions. It requires an anode, cathode, electrolyte, and an electrically conducting path.
2. At the anode, iron oxidizes to ferrous ions which then react with hydroxyl ions from the cathode to form iron hydroxide and iron oxide. The products occupy more volume than the original steel causing stresses in the concrete.
3. Chlorides from deicing salts or seawater can destroy the protective oxide layer and accelerate corrosion. Carbonation reduces concrete's alkalinity allowing the protective layer to break down.
This document provides information on calcium carbide, including its properties, manufacturing process, uses, packaging and international standards. Some key points:
- Calcium carbide is produced through heating limestone and coke to 2200-2500°C in an electric furnace. It reacts with water to produce acetylene gas.
- Its main uses are in producing acetylene for welding/cutting and calcium cyanamide as a fertilizer. It also acts as a dehydrating/reducing agent.
- The BIS specification outlines purity levels and gas yield requirements for different grades of calcium carbide. International standards also provide size classifications.
- Calcium carbide is packed in moisture
The document summarizes extraction and uses of magnesium. It describes common magnesium minerals like dolomite and magnesite. It discusses challenges in extracting magnesium through pyrometallurgical and electrometallurgical processes. The Pidgeon and Magnetotherm processes are described for pyrometallurgical extraction. The Dow process extracts magnesium from seawater through precipitation and electrolysis. Magnesium has non-structural uses like alloying, deoxidation, and cathodic protection. Structural uses include aircraft and transportation applications due to magnesium's high strength to weight ratio.
Tungsten is a transition metal that was discovered in Spain in the 1780s. It is a hard, dense metal with a high melting point that gives it important applications. Tungsten is commonly used in incandescent light bulb filaments, electronics, and to make carbides for drill bits and cutting tools due to its properties including density, hardness, and high melting point. The major deposits of tungsten are located in China.
Titanium can be extracted through Kroll's process or Hunter's process. Kroll's process involves reducing titanium tetrachloride with magnesium at 800°C to produce titanium sponge and magnesium chloride. Hunter's process reduces titanium tetrachloride with sodium in a series of steady-state reactions to produce titanium and sodium chloride. The brittle titanium sponge produced requires further processing like purification and melting to produce ductile titanium for applications such as jet engine components, air frames, and spacecraft.
The document discusses extractive metallurgy processes for zinc extraction. It describes the major zinc ores and details several pyrometallurgical and hydrometallurgical extraction processes. The key processes are roasting to produce zinc oxide from zinc sulfide ores, followed by leaching and electrolysis to recover zinc. Approximately 80% of zinc is produced via hydrometallurgical routes like roast-leach-electrowinning.
The document discusses the open hearth furnace process used in foundries. The open hearth furnace uses direct contact between fuel and metals to melt iron, aluminum, and other materials. It consists of a shallow bath capable of holding 60-300 tons of metal, with heating chambers on the sides and openings at each end to allow heated gases to burn and escape. The furnace lining depends on the impurities in the metal. Once charged and heated to 1500C, the scrap and pig iron melt over 3 hours as impurities are removed. The molten steel is then tapped and deslagged before being poured into ingots or castings.
Hydrogen embrittlement is a phenomenon that causes metals like steel, titanium, and aluminum alloys to become brittle. It occurs when hydrogen enters these metals, reducing their ductility and load bearing capacity. There are several ways hydrogen can get into metals, such as from acid cleaning, electroplating, welding, and heat treating. Once hydrogen is absorbed, even small amounts below detection levels can cause cracking or failure of parts, especially under stress. Proper baking and controlling hydrogen exposure during manufacturing processes can help prevent failures from hydrogen embrittlement.
Blast furnace process-Drain rate vs cating rate pdf 29 07 2020Anil Mistry
1. Drain rate, or the rate at which melt is removed from the furnace, should be higher than the production rate in order to prevent a build up of liquid levels in the hearth.
2. On cast time refers to the amount of time that tap holes remain open to drain liquid from the furnace. A longer on cast time supports achieving a higher drain rate than the production rate.
3. If drain rate is not higher than production rate, high liquid levels in the hearth can negatively impact burden descent and gas distribution patterns in the furnace.
Alloys contain more than one element, usually a mixture of metals, and are made for specific purposes like car parts, jewelry, and wheel rims. While pure metals have uniformly sized atoms arranged in sliding layers, alloys have atoms of different sizes that get jammed together. This makes alloys harder, stronger, and less ductile or malleable than their constituent metals. An experiment showed that bronze blocks produced smaller dents on average than copper blocks when struck with a weighted ball bearing, supporting the hypothesis that alloys are harder than pure metals.
Martensitic transformations are diffusionless, solid-state structural changes driven by shear displacements. They occur rapidly in many metal, ceramic, and polymer systems. Important examples include the transformation of austenite to martensite in steels during quenching, and the shape memory effect exploited in medical devices like stents. The Bain model originally proposed the mechanism as a combination of homogeneous lattice deformation and atomic shuffles, but has inconsistencies. Modern understanding involves dislocation or shear-based mechanisms constrained by the crystallography of the parent and product phases.
Refractory materials are required for steelmaking as they can withstand very high temperatures without undergoing chemical changes. They are needed to contain molten steel, slag and hot gases. High quality refractories are important to reduce costs as the refractory material costs are added to the overall product costs. Refractories must withstand high temperatures, thermal shocks, chemical reactions with molten materials, and abrasion. Common refractory materials include fireclay, magnesia, chromite, and alumina, which are selected based on the temperature and chemical environment they will be used in. Newer refractory application methods like monolithics and high emissivity coatings provide benefits over traditional refractory bricks.
This document studies temper embrittlement in steel samples. Temper embrittlement occurs when certain alloy steels are cooled slowly or held at temperatures from 400-660°C, resulting in decreased toughness from the precipitation of embrittling elements along grain boundaries. The study examines different types of embrittlement, remedies, and characterizes the microstructure and hardness of carbon steel samples tempered at various temperatures from 150-450°C. Hardness was found to decrease with increasing tempering temperature.
Crystal defects occur when the regular patterns of atoms in crystalline materials are interrupted. There are several types of crystal defects including point defects, line defects, and plane defects. Point defects are defects that occur at or around a single lattice point and include vacancies, interstitials, and substitutions. Vacancies occur when an atom is missing from its normal position in the crystal lattice. Interstitials occur when an atom occupies a position between normal lattice sites. Substitutions occur when a foreign atom replaces a host atom in the lattice. The presence of defects is necessary for crystals to have stability at any non-zero temperature due to the contribution of defects to entropy.
The Step by Step Process of Extracting Iron from its Ore using the Blast Furnace with details of Chemical Reactions. Question Answers based on the process of extraction of metals.
This document discusses hydrogen embrittlement, which is the loss of ductility in a material caused by hydrogen absorption. It can occur in body-centered cubic and hexagonal close-packed metals when as little as 0.0001% hydrogen is absorbed. Hydrogen is introduced through processes like corrosion and welding. It causes increased strain rate sensitivity and susceptibility to delayed fracture. Several mechanisms are proposed to explain how hydrogen causes embrittlement, including hydride formation and reducing decohesion strength. Prevention techniques include reducing corrosion, using cleaner steels, baking to remove hydrogen, proper welding practices, and alloying to reduce hydrogen diffusion.
The document discusses corrosion, which is defined as the degradation of a metal through a chemical reaction on its surface caused by its surrounding chemicals. It then discusses the chemical theory of corrosion, noting that oxygen and other gases can cause corrosion by directly reacting with metals. There are two main types of corrosion - dry corrosion, which occurs without moisture, and wet/electrochemical corrosion, which occurs when a metal is in contact with a conducting liquid. The document goes on to describe examples of different corrosion processes and methods used to protect metals from corrosion, including cathodic protection and coatings like paint.
The document discusses various methods for melting aluminium and dealing with hydrogen that can cause porosity in aluminium castings. It describes furnace types used for melting aluminium, such as reverberatory and induction furnaces. It also discusses sources of hydrogen absorption from the environment or reactions during melting, and methods for degassing molten aluminium like bubbling nitrogen or chlorine gas through the melt or using flux treatments. Pre-solidification is also mentioned as another degassing technique.
Novel electrowinning technologies are now a days has great talks among todays scientist. I heartily thanks to the behind this ppt.Namely- bhagyashree,neelu sheoran,pranitha geedigunta. thanks gls...
This document discusses diffusion and alloys in materials science. It defines diffusion as the movement of atoms in solids and describes mechanisms like vacancy and interstitial diffusion. Fick's laws of diffusion relating flux and concentration gradients are also covered. The document then discusses alloys, defining them as mixtures of elements and describing types like substitutional and interstitial solid solutions as well as intermetallic compounds. Rules for solid solubility like the Hume-Rothery rules are summarized. Superalloys are mentioned as high strength alloys that retain properties at high temperatures through mechanisms like grain boundary control.
Titanium can be extracted through Kroll's process or Hunter's process. Kroll's process involves reducing titanium tetrachloride with magnesium at 800°C to produce titanium sponge and magnesium chloride. Hunter's process reduces titanium tetrachloride with sodium in a series of steady-state reactions to produce titanium and sodium chloride. The brittle titanium sponge produced requires further processing like purification and melting to produce ductile titanium for applications such as jet engine components, air frames, and spacecraft.
The document discusses extractive metallurgy processes for zinc extraction. It describes the major zinc ores and details several pyrometallurgical and hydrometallurgical extraction processes. The key processes are roasting to produce zinc oxide from zinc sulfide ores, followed by leaching and electrolysis to recover zinc. Approximately 80% of zinc is produced via hydrometallurgical routes like roast-leach-electrowinning.
The document discusses the open hearth furnace process used in foundries. The open hearth furnace uses direct contact between fuel and metals to melt iron, aluminum, and other materials. It consists of a shallow bath capable of holding 60-300 tons of metal, with heating chambers on the sides and openings at each end to allow heated gases to burn and escape. The furnace lining depends on the impurities in the metal. Once charged and heated to 1500C, the scrap and pig iron melt over 3 hours as impurities are removed. The molten steel is then tapped and deslagged before being poured into ingots or castings.
Hydrogen embrittlement is a phenomenon that causes metals like steel, titanium, and aluminum alloys to become brittle. It occurs when hydrogen enters these metals, reducing their ductility and load bearing capacity. There are several ways hydrogen can get into metals, such as from acid cleaning, electroplating, welding, and heat treating. Once hydrogen is absorbed, even small amounts below detection levels can cause cracking or failure of parts, especially under stress. Proper baking and controlling hydrogen exposure during manufacturing processes can help prevent failures from hydrogen embrittlement.
Blast furnace process-Drain rate vs cating rate pdf 29 07 2020Anil Mistry
1. Drain rate, or the rate at which melt is removed from the furnace, should be higher than the production rate in order to prevent a build up of liquid levels in the hearth.
2. On cast time refers to the amount of time that tap holes remain open to drain liquid from the furnace. A longer on cast time supports achieving a higher drain rate than the production rate.
3. If drain rate is not higher than production rate, high liquid levels in the hearth can negatively impact burden descent and gas distribution patterns in the furnace.
Alloys contain more than one element, usually a mixture of metals, and are made for specific purposes like car parts, jewelry, and wheel rims. While pure metals have uniformly sized atoms arranged in sliding layers, alloys have atoms of different sizes that get jammed together. This makes alloys harder, stronger, and less ductile or malleable than their constituent metals. An experiment showed that bronze blocks produced smaller dents on average than copper blocks when struck with a weighted ball bearing, supporting the hypothesis that alloys are harder than pure metals.
Martensitic transformations are diffusionless, solid-state structural changes driven by shear displacements. They occur rapidly in many metal, ceramic, and polymer systems. Important examples include the transformation of austenite to martensite in steels during quenching, and the shape memory effect exploited in medical devices like stents. The Bain model originally proposed the mechanism as a combination of homogeneous lattice deformation and atomic shuffles, but has inconsistencies. Modern understanding involves dislocation or shear-based mechanisms constrained by the crystallography of the parent and product phases.
Refractory materials are required for steelmaking as they can withstand very high temperatures without undergoing chemical changes. They are needed to contain molten steel, slag and hot gases. High quality refractories are important to reduce costs as the refractory material costs are added to the overall product costs. Refractories must withstand high temperatures, thermal shocks, chemical reactions with molten materials, and abrasion. Common refractory materials include fireclay, magnesia, chromite, and alumina, which are selected based on the temperature and chemical environment they will be used in. Newer refractory application methods like monolithics and high emissivity coatings provide benefits over traditional refractory bricks.
This document studies temper embrittlement in steel samples. Temper embrittlement occurs when certain alloy steels are cooled slowly or held at temperatures from 400-660°C, resulting in decreased toughness from the precipitation of embrittling elements along grain boundaries. The study examines different types of embrittlement, remedies, and characterizes the microstructure and hardness of carbon steel samples tempered at various temperatures from 150-450°C. Hardness was found to decrease with increasing tempering temperature.
Crystal defects occur when the regular patterns of atoms in crystalline materials are interrupted. There are several types of crystal defects including point defects, line defects, and plane defects. Point defects are defects that occur at or around a single lattice point and include vacancies, interstitials, and substitutions. Vacancies occur when an atom is missing from its normal position in the crystal lattice. Interstitials occur when an atom occupies a position between normal lattice sites. Substitutions occur when a foreign atom replaces a host atom in the lattice. The presence of defects is necessary for crystals to have stability at any non-zero temperature due to the contribution of defects to entropy.
The Step by Step Process of Extracting Iron from its Ore using the Blast Furnace with details of Chemical Reactions. Question Answers based on the process of extraction of metals.
This document discusses hydrogen embrittlement, which is the loss of ductility in a material caused by hydrogen absorption. It can occur in body-centered cubic and hexagonal close-packed metals when as little as 0.0001% hydrogen is absorbed. Hydrogen is introduced through processes like corrosion and welding. It causes increased strain rate sensitivity and susceptibility to delayed fracture. Several mechanisms are proposed to explain how hydrogen causes embrittlement, including hydride formation and reducing decohesion strength. Prevention techniques include reducing corrosion, using cleaner steels, baking to remove hydrogen, proper welding practices, and alloying to reduce hydrogen diffusion.
The document discusses corrosion, which is defined as the degradation of a metal through a chemical reaction on its surface caused by its surrounding chemicals. It then discusses the chemical theory of corrosion, noting that oxygen and other gases can cause corrosion by directly reacting with metals. There are two main types of corrosion - dry corrosion, which occurs without moisture, and wet/electrochemical corrosion, which occurs when a metal is in contact with a conducting liquid. The document goes on to describe examples of different corrosion processes and methods used to protect metals from corrosion, including cathodic protection and coatings like paint.
The document discusses various methods for melting aluminium and dealing with hydrogen that can cause porosity in aluminium castings. It describes furnace types used for melting aluminium, such as reverberatory and induction furnaces. It also discusses sources of hydrogen absorption from the environment or reactions during melting, and methods for degassing molten aluminium like bubbling nitrogen or chlorine gas through the melt or using flux treatments. Pre-solidification is also mentioned as another degassing technique.
Novel electrowinning technologies are now a days has great talks among todays scientist. I heartily thanks to the behind this ppt.Namely- bhagyashree,neelu sheoran,pranitha geedigunta. thanks gls...
This document discusses diffusion and alloys in materials science. It defines diffusion as the movement of atoms in solids and describes mechanisms like vacancy and interstitial diffusion. Fick's laws of diffusion relating flux and concentration gradients are also covered. The document then discusses alloys, defining them as mixtures of elements and describing types like substitutional and interstitial solid solutions as well as intermetallic compounds. Rules for solid solubility like the Hume-Rothery rules are summarized. Superalloys are mentioned as high strength alloys that retain properties at high temperatures through mechanisms like grain boundary control.
1. BORÜRLER
NECMETTİN ERBAKAN ÜNİVERSİTESİ
Mühendislik ve Mimarlık Fakültesi
Metalurji ve Malzeme Mühendisliği Bölümü
İleri Teknoloji Seramikler Dersi
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
2. BOR NEDİR?
(What’s Boron?)
• Elmastan sonra en sert madendir.
• Ergime sıcaklığı: 2076-3000
°C’dir.
• Buharlaşma sıcaklığı :3927 °C’dir.
• Sertlik (Vickers) : 5000 HV
• Bor 2.33 gr/cm3 yoğunluklu kristal
ve 2.3 gr/cm3 yoğunluklu amorf
olmak üzere iki şekilde bulunur.
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
2/43
3. BOR NEDİR?
• Doğada yaklaşık 230 çeşit Bor minerali vardır.
• Ticari değere sahip 7 bor minerali vardır.
Boraks (Tinkal) Kernit (Razorit) Kolemanit Uleksit
Propertit Pandermit Borik Asit
3/43NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
4. (Borik Asit -H3BO3)
(Boric Acid)
• Bor’un oda sıcaklığında elektrik iletkenliği
zayıftır fakat yüksek sıcaklıklarda çok
yüksektir.
• Bor kimyasal olarak ametaldir.
• Bor, normal sıcaklıklarda hava, su ve
HCl/HF ile soy davranış gösterir.
• Sadece yüksek konsantrasyonlu nitrik asit ile
sıcak ortamda borik asite dönüşebilmektedir.
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NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
5. • Borürler, bor ve daha az elektronegatif
elementlerden oluşan bileşiklerdir.
• Çoğu borür, genel formülü MnBm olan ve
borun negatif yüklü olduğu metal
bileşiklerdir.
• Metal-bor oranına bağlı olarak, sonuç bor
açısından çok zengin olabilir.
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BORÜR NEDİR?
(What’s Boride?)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
6. • Alkali metaller gibi elektropozitif metaller,
bor açısından zengin, örneğin MB2 gibi
bileşikler oluşturur.
• Demir gibi daha az elektropozitif olan
metaller, M2B metalleri açısından zengin
borürler oluşturur.
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NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
BORÜR NEDİR?
(What’s Boride?)
Fe(II)Boride
Al Diboride
7. 7/43
BORÜR NEDİR?
Fe(II) Borür ve Al Diborür:
(Fe(II) Boride and Al Diboride)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
8. • Yüksek sıcaklıklarda saf oksijen ile
reaksiyona girerek bor oksit (B2Oj)
oluşturur.
Bor Trioksit (B2O3)
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NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
Bor Oksit (B2Oj)
(Boron Oxide)
9. • Aynı koşullarda nitrojen ile bor nitrat (BN)
ve titanyum diyorit (TiBj) gibi endüstride
kullanılan bileşikler oluşabilmektedir.
• Bor elementinin kimyasal özellikleri
morfolojisine ve tane büyüklüğüne
bağlıdır.
• Mikron ebadındaki amorf bor kolaylıkla ve
bazen şiddetli olarak reaksiyona girerken,
kristalin bor kolay reaksiyona girmez.
9/43
Bor Nitrat (BN)- Titanyum Diyorit (TiBj)
(Boron Nitrate-Titanium Diorite)
Bor Nitrat (BN)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
10. • Titanyum diborür, bir geçiş metali borürü olup, Ti-B sistemine ait ağırlıkça % 31,1 bor içeren bir
metal borürdür. Hegzagonal yapıdadır.
Titanyum Diborür (TiB2)
(Titanium Diboride)
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NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
11. • Yüksek sertlik,
• Yüksek ergime noktası (3.230 °C),
• Yüksek elastik modülü,
• Yüksek sürtünme katsayısı,
• Mükemmel aşınma ve korozyon direnci,
• İyi termal ve elektriksel iletkenlik,
• 1700 °C’ye kadar kimyasal ve ısıl kararlılık,
• Ergimiş metallere, HCl ve HF’e karşı dayanıklılık.
• TiB2 1000°C nin üstünde hava ile oksidasyona karşı
dirençlidir.
Titanyum Diborür (TiB2)
Üstün Özellikleri:
(High Properties)
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NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
12. • HF’e ve HCl’e karşı dirençli olsa da HNO3 ve H2SO4 ile etkileşir.
• Alkaliler ile kolay bir şekilde etkileşir.
12/43
Titanyum Diborür (TiB2)
Zayıf Özellikleri:
(Negative Properties)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
HNO3 - Nitrik Asit H2SO4 - Sülfürik Asit
13. • Sinterlemeye karşı dirençleri yüksektir. (1600-1700°C)
• Genellikle izostatik presleme veya sıcak press ile yoğunlaştırılır.
• TiB2’nin yüksek saflıkta elde edilmesi için basınçsız sinterleme yöntemi kullanılır.
• Yüksek sertliğinden dolayı pek çok sanayi alanında tercih edilir.
• Şekil vermedeki işlenebilirliğini zorlaştırdığı için TiB2’nin tek başına kullanılmasından
ziyade kompozit olarak kullanılmaya itmektedir.
13/43
Titanyum Diborür (TiB2)
Presleme-Sinterleme:
(Pressing-Sintering)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
İzostatik Pres
15. Çok çeşitli üretim yöntemleri vardır;
• Titanyum ve Borun katı hal reaksiyonu,
• Karbotermik indirgeme,
• Metalotermik indirgeme,
• Ergimiş tuz elektrolizi,
• Aerosol prosesi,
• Ve PVD yöntemleridir.
Titanyum Diborür (TiB2)
Üretimi: (Production)
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NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
16. • Üretim yöntemleri arasında en direkt olanıdır.
• Bu yöntemle titanyum diborür üretimi toz formda
ve yüksek saflıkta ürün elde edilmesine olanak
tanıdığı gibi kompozisyon kontrolü de
mümkündür.
Bu yöntemin avantajları olduğu gibi
dezavantajları da vardır;
• Titanyum (Ti) ve bor (B) tozları oksijen ile çok
reaktiftirler.
• Bu yüzden yüzeylerinde oksit tabakaları oluşabilir.
• Ayrıca güçlü ekzotermik reaksiyonlar sonucu
tehlikelere sebep olabilirler.
Titanyum Diborür (TiB2)
Titanyum ve Borun Katı Hal Reaksiyonu ile Üretimi:
(Production by Solid State Reaction of Titanium and Boron)
Ti + 2B=TiB2
TiB2 üretimi için elementel Titanyum ve
Bor kullanımı yerine oksitleri
tercih edilmektedir.
16/43
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
17. • Ucuz hammaddelerden dolayı yaygın
kullanılan basit bir yöntemdir.
• Karbotermal indirgeme karbür, borür veya
nitrür seramik tozlarının üretiminde kullanılan
bir yöntemdir.
• Borürlerin sentezi için metal oksit ve karbonun
yanı sıra bor kaynağı olarak elementel bor
veya bor içeren bir karbon kaynağı
kullanılması gereklidir.
Titanyum Diborür (TiB2)
Karbotermal Yöntem ile Üretimi: (Production by Carbotermal Method)
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18. • Bu yöntemle titanyum diborür üretimi,
çok enerji gerektiren bir prosestir.
• Özellikle hammaddelerin reaksiyona
girmesi için ısıtılıp daha sonra da
reaksiyonun gerçekleşmesi için büyük
miktarda enerji harcanır.
• Bu yolla hazırlanan tozlar nispeten
büyük tanecik boyutuna sahip
olmaktadır.
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NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
Titanyum Diborür (TiB2)
Karbotermal Yöntem ile Üretimi: (Production by Carbotermal Method)
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Karbotermal yolla titanyum diborür üretimi için önerilen iki ayrı tepkime vardır;
• Kimyasal sistem olarak iki reaksiyon birbirine
çok benzer, fakat Tepkime (1) sonucu oluşan
CO miktarı daha azdır ve (2). Tepkimeye göre
daha az sıcaklık ve enerji gerektirir.
• Genellikle tepkime (1), TiB2 üretiminde daha
çok tercih edilen reaksiyondur.
TiO2 + 1/2B4C + 3/2C = TiB2 + 2CO (1) (1173°C’un üzerinde)
TiO2 + B2O3 + 5C = TiB2 + 5CO (2) ( 1430 °C civarı)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
Titanyum Diborür (TiB2)
Karbotermal Yöntem ile Üretimi: (Production by Carbotermal Method)
20. • Titanyum oksit (TiO2) ve borik asitin (B2O3)
uygun bir redükleyici ajan ile indirgenmesi ile
gerçekleştirilmektedir.
• Metalotermik indirgeme, bir metal oksit veya
metal halojenür ile diğer bir metal arasında
meydana gelen bir yer değiştirme
reaksiyonudur.
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Titanyum Diborür (TiB2)
Metalotermik Yöntem ile Üretimi:
(Production by Metallothermic Reduction Method)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
Meı X + Meıı= Meı + Meıı X (A)
(X=oksijen, halojen)
21. • Termodinamik olarak tepkime (A)’nın gerçekleşmesi için reaksiyonun Gibbs serbest
enerjisinin negatif olması gereklidir, bu da Meıı ’nin oksijene veya halojenürlere olan
ilgisinin Meı ’e göre daha fazla olmasını gerektirmektedir.
• Metalotermik indirgemede kullanılan indirgeyiciler silisyum (Si), alüminyum (Al),
magnezyum (Mg) ve kalsiyumdur (Ca).
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Titanyum Diborür (TiB2)
Metalotermik Yöntem ile Üretimi:
(Production by Metallothermic Reduction Method)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
Meı X + Meıı= Meı + Meıı X (A) ΔG= ΔH-T ΔS<0
22. • Titanyum oksit termodinamik olarak silisyum ile
indirgenemediği için silisyum, titanyum diborür
üretimi için uygun bir indirgeyici değildir.
• Alüminyum, magnezyum ve kalsiyum hem titanyum
oksiti hem de borik asidi indirgeyebildiği için,
titanyum diborür üretimi için kullanılan
indirgeyicilerdir.
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Titanyum Diborür (TiB2)
Metalotermik Yöntem ile Üretimi:
(Production by Metallothermic Reduction Method)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
TiO2 + B2O3 + 5Mg = TiB2 + 5MgO (B)
∆H298 = 3949,59 J/1 g ürün
TiO2 + B2O3 + 5Ca = TiB2 + 5CaO (C)
∆H298 = 3538,98 J / 1 g ürün
3TiO2 + 3B2O3 + 10Al = 3TiB2 + 5Al2O3 (D)
∆H298 = 3572,91 J / 1 g ürün
23. • Magnezyum, alüminyuma göre tercih edilmektedir.
Çünkü;
(B) Reaksiyonu sonucunda oluşan Magnezyum Oksit HCl ile liç edilerek
uzaklaştırılabilir ve yüksek saflıkta Titanyum Diborür elde edilebilir.
TiO2 + B2O3 + 5Mg = TiB2 + 5MgO (B) ∆H298 = 3949,59 J/1 g ürün
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Titanyum Diborür (TiB2)
Metalotermik Yöntem ile Üretimi:
(Production by Metallothermic Reduction Method)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
24. • Titanyum diborür, ZrB2 , TaB2 , YbB6 , SrB6
gibi çeşitli borür bileşiklerinin ergimiş tuz
elektrolizi ile elektrokimyasal olarak
sentezlenmesi mümkündür.
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Titanyum Diborür (TiB2)
Ergimiş Tuz Elektrolizi Yöntemi ile Üretimi:
(Production by Melted Salt Electrolysis Method)
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Ergimiş Tuz Elektrolizi Yöntemi Şematik Gösterimi
25. • Aerosol prosesleri, gaz fazında gerçekleşen reaksiyonlar vasıtası ile toz üretimini amaçlayan
proseslerdir.
• Hammaddenin gaz veya parçacık (katı veya sıvı) olmasına göre iki ana gruba ayrılmaktadır.
• Bu prosesler, tek aşamalı üretime yönelik, fazla reaksiyon kademesi içermeyen ve katı
hammaddeler ile gerçekleştirilen işlemlere göre daha kısa süreler gerektiren süreçlerdir.
• Aerosol prosesleri yüksek saflıkta ürünlerin yüksek verimlerle üretilebilmesini sağlayabilen
yöntemlerdir.
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NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
Titanyum Diborür (TiB2)
Aerosol Prosesi ile TiB2 Tozu Sentezi:
(TiB2 Powder Synthesis by Aerosol Process)
26. • PVD çeşitli refrakter malzemeleri
ergime sıcaklıklarının altındaki
sıcaklıklarda kaplama olarak
kullanmaya izin veren bir yöntemdir.
• Bu teknik ile süreye bağlı olmak üzere,
kalınlığı bir mikronla birkaç milimetre
arasında değişen kaplamalar yapmak
mümkündür.
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Titanyum Diborür (TiB2)
PVD Yöntemi:
(PVD Method)
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27. • Titanyum diborür 1000-1300°C arasında, 1 atm basınçta titanyum tetraklorür ve bor
tetraklorürün hidrojen ile indirgenmesi ile üretilmektedir. (E)
TiCl4 + 2BCl3 + 5H2 = TiB2 + 10HCl (E)
• Bu reaksiyon güçlü bir ekzotermik reaksiyondur.
• Reaksiyonun gerçekleştiği sıcaklıklarda hızla tane büyümesi olduğundan bu yöntemle küçük
tane boyutlu titanyum diborür üretimi imkânsızdır.
• Bu sorunun çözümü için alternatif olarak Tepkime (F)’deki reaksiyon kullanılmaktadır.
10TiCl3(g) + 2BCl3(g) +TiB2(L) + 9TiCl4(g) (F)
• Bu yöntem ile mikron altı titanyum diborür üretimi mümkündür.
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Titanyum Diborür (TiB2)
PVD Yöntemi:
(PVD Method)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
28. • Titanyum diborür esaslı malzemelerin sertlik, termal ve elektriksel özelliklerinin
kombinasyonu bu malzemeyi birçok mühendislik uygulaması için cazip hale getirmektedir.
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Titanyum Diborür (TiB2)
Kullanım Alanları:
(Application Areas)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
29. • Kumlama ve sert partiküllerin püskürtüldüğü nozullarda kullanılır.
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Titanyum Diborür (TiB2)
Kullanım Alanları:
(Application Areas)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
30. • Titanyum diborür ergimiş alüminyum ve
kriyolite karşı inert olmanın yanı sıra yüksek
elektrik iletkenliğine sahip olması, bu
malzemenin alüminyum metalurjisinde
katot, elektrot ve termoçift kılıfı olarak
kullanılmasını sağlamaktadır.
• Monolitik titanyum diborür, Hall Héroult
hücrelerinde alüminyum elektrolizinde
kullanılmaktadır.
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Titanyum Diborür (TiB2)
Kullanım Alanları:
(Application Areas)
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Titanyum Diborür (TiB2)
Kullanım Alanları:
(Application Areas)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
• Askeri uygulamalarda seramik zırh olarak kullanılır.
• Amerika Birleşik Devletleri TiB2 kompozitlerini balistik zırh olarak silahlı kuvvetlerinin
envanterinde bulunan zırhlı araçların bazılarında kullanmaktadır.
32. • Yüksek sıcaklığa maruz kalan
kısımlarda kaplama veya parça olarak
(örneğin; motor parçalarında, roket
motor parçalarında, metal ergitme
nozülleri ve jet motoru parçalarında)
kullanılmaktadır.
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Titanyum Diborür (TiB2)
Kullanım Alanları:
(Application Areas)
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33. • Fiber optik kabloların koruma altlığı olarak kullanılır.
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Titanyum Diborür (TiB2)
Kullanım Alanları:
(Application Areas)
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34. • Kimyasal kararlılığıyla aşınmaya dayanıklı kısımlar ve kesici takım uçlarının üretiminde kullanılır.
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Titanyum Diborür (TiB2)
Kullanım Alanları:
(Application Areas)
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Lantanyum Hekzaborür (LaB6)
(Lanthanum Hexaboride)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
• İnorganik bir kimyasaldır.
• 2210°C erime noktasına sahip, suda ve
hidroklorik asitte çözünmeyen refrakter
seramik malzemedir.
• Düşük bir çalışma fonksiyonuna ve bilinen
en yüksek elektron emisyonlarından birine
sahiptir ve vakumda stabildir.
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• Yoğunluk: 4,72 g/cm³
• Erime Noktası: 2.210 °C
• Molar Kütle: 203,78 g/mol
• Kristal Yapısı: Kübik kristal yapı
• Suda Çözünürlük: insoluble
Lantanyum Hekzaborür (LaB6)
Genel Özellikler:
(General Properties)
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Lantanyum Hekzaborür (LaB6)
Kullanım Alanları:
(Application Areas)
• Lantan hekzaborürün temel kullanımı, tek bir
kristal olarak veya fiziksel buhar biriktirme ile
çökeltilen bir kaplama olarak sıcak katotlarda
kullanılır.
• Lantan hekzaborür (LaB6) ve seryum hekzaborür
(CeB6) gibi hekzaborürler, 2,5 eV civarında
düşük çalışma fonksiyonlarına sahiptir.
• Ayrıca LaB6 katot zehirlenmesine karşı
dirençlidir.
Lantanyum Hekzaborür (LaB6) Filamentler / Katotlar
38. • Hekzaborür katotlar, tungsten katotlardan yaklaşık
on kat daha parlaktır ve 10-15 kat daha uzun
ömürlüdür.
Heksaborür katotların kullanıldığı cihazlar ve
teknikler arasında;
• Elektron mikroskopları,
• Mikrodalga tüpleri,
• Elektron litografisi,
• Elektron ışını kaynağı,
• X-ışını tüpleri ve
• Serbest elektron lazerleri bulunur.
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Lantanyum Hekzaborür (LaB6)
Kullanım Alanları:
(Application Areas)
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Lantanyum Hekzaborür (LaB6) Filamentler / Katotlar
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Lantanyum Hekzaborür (LaB6)
Kullanım Alanları:
(Application Areas)
Lantanyum Hekzaborür (LaB6) Filamentler / Katotlar
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020
• LaB6 Tabancalarının tungsten
tabancalarından daha yüksek bir vakum
altında kullanılması gerektiğini ve LaB6
tabancalarının daha yüksek parlaklık, daha
küçük elektron kaynağı ve daha az enerji
yayılımı sağladığını göstermektedir.
• Bu nedenle, LaB6 tabancaları, analitik
elektron mikroskopları için tungsten
tabancalarından daha uygundur.
40. Solar Enerji Uygulamaları için Lantanyum Hekzaborür
(Lanthanum Hexaboride for Solar Energy Applications)
• Konsantre Güneş Enerjisi (CSP) sistemlerinde
katı soğurucular için olası adaylar olarak LaB6
bazlı malzemelerin optik özelliklerini
araştırılmıştır.
• Dökme LaB6 malzemeleri, ticari tozlardan
başlayarak sıcak presleme ile termal olarak
birleştirilmiştir.
• Güneş soğurma ve spektral seçicilik
özelliklerini değerlendirmek için, farklı
bileşimler, gözeneklilikler ve yüzey pürüzlülüğü
göz önünde bulundurularak ultraviyole ile orta
kızılötesi arasında oda sıcaklığı yarı küresel
yansıma spektrumları ölçülmüştür. (1100 °K)
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41. • LaB6 , Silikon Karbür gibi gerçek
tesislerdeki en gelişmiş güneş emici
malzemeyle karşılaştırılabilir bir güneş
emiciliğine sahiptir.
• LaB6 Aynı zamanda hem doğrudan yüksek
sıcaklıkta güneş emici hem de elektron
kaynağı olarak hareket edebilmesi için
termiyonik bir malzeme olmak için çekici
özelliklere sahiptir.
• Gelecekte yoğunlaşan güneş termiyonik
sistemlerinde, sistem karmaşıklığını önemli
ölçüde azaltacaktır.
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Solar Enerji Uygulamaları için Lantanyum Hekzaborür
(Lanthanum Hexaboride for Solar Energy Applications)
NECMETTİN ERBAKAN ÜNİVERSİTESİ 17010111003 EMRE AVCI 29 ARA 2020