scholarly journals Titanium production by magnesium thermal reduction in the electroslag process

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ernests Platacis ◽  
Imants Kaldre ◽  
Ervīns Blumbergs ◽  
Linards Goldšteins ◽  
Vera Serga
Keyword(s):  
Titanium Sponge ◽  
Pure Titanium ◽  
High Strength ◽  
Batch Process ◽  
Thermal Reduction ◽  
Reduction Reaction ◽  
Metallic Titanium ◽  
Kroll Process ◽  
Product Separation ◽  
Magnesium Thermal Reduction

AbstractTitanium is widely used in specific applications due to its high strength, low density and good chemical stability. Despite it is one of the most abundant elements in the earth’s crust, it is very expensive, because production of pure metallic titanium is very complex. Kroll process is the way how most of the titanium is produced nowadays. Shortages of this process are that it is batch process and it is very energy exhaustive, because titanium sponge material after reduction reaction needs complex post processing to isolate pure titanium. In this work we describe and experimentally investigate technology for Ti production from titanium tetrachloride using combined Kroll and electroslag process. Such process allows to achieve better reaction product separation by molten slag and process can potentially be continuous, thus technological process to produce metallic titanium can be significantly shortened.

Effect of Catalyst on the Preparation of Silicon Carbide Whiskers from Silica and Carbon

2007 ◽  
Vol 336-338 ◽  
pp. 1304-1306
Author(s):  
Mu Wen Xie ◽  
Long Hao Qi ◽  
Qiang Xu
Keyword(s):  
Silicon Carbide ◽  
Fibrous Material ◽  
High Strength ◽  
Thermal Reduction ◽  
Reduction Reaction ◽  
Subsequent Evolution ◽  
Silicon Carbide Whiskers ◽  
Nickel Cobalt ◽  
Metal Ceramic ◽  
Iron Nickel

Silicon carbide whiskers (SiCw) as a kind of high strength fibrous material are widely used in the reinforcement of metal, ceramic and polymer. In this paper preparation of Silicon carbide whiskers by carbon thermal reduction reaction from the mixture of Silica and carbon was investigated with an emphasis on the study of the effect of catalyst. Fe, Co, Ni and their compounds were used as catalyst in this study. Since vapor–liquid–solid (VLS) mechanism was found to be responsible for the growth of whiskers, the formation of catalyst and its subsequent evolution on whisker nucleation, growth and appearance was a subject of extensive research. The catalyst that has the best effect among iron, nickel, cobalt and their compounds was made certain by comparing the products.

In vitro Behaviour of Alumina-Hydroxiapatite Composites Coatings

2018 ◽  
Vol 69 (6) ◽  
pp. 1416-1418
Author(s):  
Alexandru Szabo ◽  
Ilare Bordeasu ◽  
Ion Dragos Utu ◽  
Ion Mitelea
Keyword(s):  
Pure Titanium ◽  
Titanium Substrate ◽  
High Strength ◽  
Biological Properties ◽  
Commercially Pure Titanium ◽  
Hvof Spraying ◽  
Before And After ◽  
Sbf Solution ◽  
Oxygen Fuel

Hydroxyapatite (HA) is a very common material used for biomedical applications. Usually, in order to improve its poor mechanical properties is combined or coated with other high-strength materials.The present paper reports the manufacturing and the biocompatibility behaviour of two different biocomposite coatings consisting of alumina (Al2O3) and hydroxyapatite (HA) using the high velocity oxygen fuel (HVOF) spraying method which were deposited onto the surface of a commercially pure titanium substrate. The biological properties of the Al2O3-HA materials were evaluated by in vitro studies. The morphology of the coatings before and after their immersing in the simulated body fluid (SBF) solution was characterized by scanning electron microscopy (SEM). The results showed an important germination of the biologic hydroxyapatite crystallite on the surface of both coatings.

scholarly journals Anti-Galling Cold, Dry Forging of Pure Titanium by Plasma-Carburized AISI420J2 Dies

2021 ◽  
Vol 11 (2) ◽  
pp. 595
Author(s):  
Tatsuhiko Aizawa ◽  
Tomoaki Yoshino ◽  
Yohei Suzuki ◽  
Tomomi Shiratori
Keyword(s):  
Pure Titanium ◽  
Solid Lubrication ◽  
Cold Forging ◽  
Contact Interface ◽  
Metallic Titanium ◽  
Low Friction ◽  
Debris Particles ◽  
Titanium Wire ◽  
Oxide Debris

A bare AISI420J2 punch often suffers from severe adhesion of metallic titanium as well as titanium oxide debris particles in dry, cold forging of biomedical titanium alloys. This punch was plasma-carburized at 673 K for 14.4 ks to harden it up to 1200 HV on average and to achieve carbon supersaturation in the carburized layer. This plasma-carburized punch was employed in the cold, dry forging of a pure titanium wire into a flat plate while reducing the thickness by 70%. The contact interface width approached the forged workpiece width with increasing the reduction ratio. This smaller bulging deformation reveals that the workpiece is upset by homogeneous plastic flow with a lower friction coefficient. This low-friction and anti-galling forging process was sustained by an in situ solid lubrication mechanism. Unbound free carbon was isolated from the carbon-supersaturated AISI420J2 matrix and deposited as a thin tribofilm to protect the contact interface from mass transfer of metallic titanium.

A modified graphitic carbon nitride (MCN)/Fe3O4 composite as a super electromagnetic wave absorber

2021 ◽  
Author(s):  
Xiaoyu Zhu ◽  
Hongfang Qiu ◽  
Ping Chen
Keyword(s):  
Electromagnetic Wave ◽  
Nitrogen Content ◽  
Carbon Nitride ◽  
Thermal Reduction ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Magnesium Thermal Reduction

The nitrogen content of g-C3N4 was reduced by magnesium thermal reduction to obtain porous C (MCN), and MCN was combined with Fe3O4 particles by decomposition of ferric acetylacetonate.

scholarly journals On the Role of the Cathode for the Electro-oxidation of Perfluorooctanoic Acid

2020 ◽  
Author(s):  
Alicia Garcia-Costa ◽  
André Savall ◽  
Juan A. Zazo ◽  
Jose A. Casas ◽  
Karine Groenen Serrano
Keyword(s):  
Electrochemical Techniques ◽  
High Strength ◽  
Perfluorooctanoic Acid ◽  
Reduction Reaction ◽  
Adsorbed Hydrogen ◽  
Boron Doped Diamond ◽  
Bdd Anode ◽  
Boron Doped ◽  
Initial Ph

Perfluorooctanoic acid (PFOA), C7F15COOH, has been widely employed over the past fifty years, causing an environmental problem due to its dispersion and low biodegradability. Furthermore, the high stability of this molecule, conferred by the high strength of the C-F bond makes it very difficult to remove. In this work, electrochemical techniques are applied for PFOA degradation in view to study the influence of the cathode on defluorination. For this purpose, boron doped diamond (BDD), Pt, Zr and stainless steel have been tested as cathodes working with BDD anode at low electrolyte concentration (3.5 mM) to degrade PFOA at 100 mg/L. Among these cathodic materials, Pt improves the defluorination reaction. The electro-degradation of a PFOA molecule starts by a direct exchange of one electron at the anode and then follows a complex mechanism involving reaction with hydroxyl radicals and adsorbed hydrogen on the cathode. It is assumed that Pt acts as an electrocatalyst, enhancing PFOA defluorination by the reduction reaction of perfluorinated carbonyl intermediates on the cathode. The defluorinated intermediates are then more easily oxidized by HO• radicals. Hence, high mineralization (xTOC: 76.1%) and defluorination degrees (xF-: 58.6%) were reached with Pt working at current density j = 7.9 mA/cm2. This BDD-Pt system reaches a higher efficiency in terms of defluorination for a given electrical charge than previous works reported in literature. Influence of the electrolyte composition and initial pH are also explored.

Molten-salt nitridation synthesis of cubic ZrN nanopowders at low temperature via magnesium thermal reduction

2018 ◽  
Vol 44 (7) ◽  
pp. 8710-8715 ◽  
Author(s):  
Yang Chen ◽  
Chengji Deng ◽  
Chao Yu ◽  
Jun Ding ◽  
Hongxi Zhu
Keyword(s):  
Low Temperature ◽  
Molten Salt ◽  
Thermal Reduction ◽  
Magnesium Thermal Reduction

scholarly journals On the Role of the Cathode for the Electro-Oxidation of Perfluorooctanoic Acid

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 902
Author(s):  
Alicia L. Garcia-Costa ◽  
Andre Savall ◽  
Juan A. Zazo ◽  
Jose A. Casas ◽  
Karine Groenen Serrano
Keyword(s):  
Electrochemical Techniques ◽  
High Strength ◽  
Perfluorooctanoic Acid ◽  
Reduction Reaction ◽  
Adsorbed Hydrogen ◽  
Boron Doped Diamond ◽  
Bdd Anode ◽  
Boron Doped ◽  
Initial Ph

Perfluorooctanoic acid (PFOA), C7F15COOH, has been widely employed over the past fifty years, causing an environmental problem because of its dispersion and low biodegradability. Furthermore, the high stability of this molecule, conferred by the high strength of the C-F bond makes it very difficult to remove. In this work, electrochemical techniques are applied for PFOA degradation in order to study the influence of the cathode on defluorination. For this purpose, boron-doped diamond (BDD), Pt, Zr, and stainless steel have been tested as cathodes working with BDD anode at low electrolyte concentration (3.5 mM) to degrade PFOA at 100 mg/L. Among these cathodic materials, Pt improves the defluorination reaction. The electro-degradation of a PFOA molecule starts by a direct exchange of one electron at the anode and then follows a complex mechanism involving reaction with hydroxyl radicals and adsorbed hydrogen on the cathode. It is assumed that Pt acts as an electrocatalyst, enhancing PFOA defluorination by the reduction reaction of perfluorinated carbonyl intermediates on the cathode. The defluorinated intermediates are then more easily oxidized by HO• radicals. Hence, high mineralization (xTOC: 76.1%) and defluorination degrees (xF−: 58.6%) were reached with Pt working at current density j = 7.9 mA/cm2. This BDD-Pt system reaches a higher efficiency in terms of defluorination for a given electrical charge than previous works reported in literature. Influence of the electrolyte composition and initial pH are also explored.

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