Author: André Anders
Publisher: Springer Science & Business Media
ISBN: 0387791086
Category : Science
Languages : en
Pages : 555
Book Description
Cathodic arcs are among the longest studied yet least understood objects in science. Plasma-generating, tiny spots appear on the cathode; they are highly dynamic and hard to control. With an approach emphasizing the fractal character of cathode spots, strongly fluctuating plasma properties are described such as the presence of multiply charged ions that move with supersonic velocity. Richly illustrated, the book also deals with practical issues, such as arc source construction, macroparticle removal, and the synthesis of dense, well adherent coatings. The book spans a bridge from plasma physics to coatings technology based on energetic condensation, appealing to scientists, practitioners and graduate students alike.
Cathodic Arcs
Author: André Anders
Publisher: Springer Science & Business Media
ISBN: 0387791086
Category : Science
Languages : en
Pages : 555
Book Description
Cathodic arcs are among the longest studied yet least understood objects in science. Plasma-generating, tiny spots appear on the cathode; they are highly dynamic and hard to control. With an approach emphasizing the fractal character of cathode spots, strongly fluctuating plasma properties are described such as the presence of multiply charged ions that move with supersonic velocity. Richly illustrated, the book also deals with practical issues, such as arc source construction, macroparticle removal, and the synthesis of dense, well adherent coatings. The book spans a bridge from plasma physics to coatings technology based on energetic condensation, appealing to scientists, practitioners and graduate students alike.
Publisher: Springer Science & Business Media
ISBN: 0387791086
Category : Science
Languages : en
Pages : 555
Book Description
Cathodic arcs are among the longest studied yet least understood objects in science. Plasma-generating, tiny spots appear on the cathode; they are highly dynamic and hard to control. With an approach emphasizing the fractal character of cathode spots, strongly fluctuating plasma properties are described such as the presence of multiply charged ions that move with supersonic velocity. Richly illustrated, the book also deals with practical issues, such as arc source construction, macroparticle removal, and the synthesis of dense, well adherent coatings. The book spans a bridge from plasma physics to coatings technology based on energetic condensation, appealing to scientists, practitioners and graduate students alike.
Advanced Techniques for Surface Engineering
Author: W. Gissler
Publisher: Springer Science & Business Media
ISBN: 940170631X
Category : Technology & Engineering
Languages : en
Pages : 402
Book Description
Today's shortages of resources make the search for wear and corrosion resistant materials one of the most important tasks of the next century. Since the surface of a material is the location where any interaction occurs, it is that there the hardest requirements on the material are imposed: to be wear resistant for tools and bearings; to be corrosion resistant for turbine blades and tubes in the petrochemical industry; to be antireflecting for solar cells; to be decorative for architectural panels and to combine several of these properties in other applications. Surface engineering is the general term that incorporates all the techniques by which a surface modification can be accomplished. These techniques include both coating and modification of the surface by ion implantation and laser beam melting. In recent years a continuously growing number of these techniques were developed to the extent that it became more and more difficult to maintain an overlook and to understand which of these highly differentiated techniques might be applied to resolve a given surface engineering problem. A similar development is also occuring for surface characterization techniques. This volume contains contributions from renowned scientists and engineers to the Eurocourse the aim of which was to inform about the various techniques and to give a comprehensive survey of the latest development on this subject.
Publisher: Springer Science & Business Media
ISBN: 940170631X
Category : Technology & Engineering
Languages : en
Pages : 402
Book Description
Today's shortages of resources make the search for wear and corrosion resistant materials one of the most important tasks of the next century. Since the surface of a material is the location where any interaction occurs, it is that there the hardest requirements on the material are imposed: to be wear resistant for tools and bearings; to be corrosion resistant for turbine blades and tubes in the petrochemical industry; to be antireflecting for solar cells; to be decorative for architectural panels and to combine several of these properties in other applications. Surface engineering is the general term that incorporates all the techniques by which a surface modification can be accomplished. These techniques include both coating and modification of the surface by ion implantation and laser beam melting. In recent years a continuously growing number of these techniques were developed to the extent that it became more and more difficult to maintain an overlook and to understand which of these highly differentiated techniques might be applied to resolve a given surface engineering problem. A similar development is also occuring for surface characterization techniques. This volume contains contributions from renowned scientists and engineers to the Eurocourse the aim of which was to inform about the various techniques and to give a comprehensive survey of the latest development on this subject.
Plasma and Spot Phenomena in Electrical Arcs
Author: Isak Beilis
Publisher: Springer Nature
ISBN: 3030447472
Category : Science
Languages : en
Pages : 1137
Book Description
This book is devoted to a thorough investigation of the physics and applications of the vacuum arc – a highly-ionized metallic plasma source used in a number of applications – with emphasis on cathode spot phenomena and plasma formation. The goal is to understand the origins and behavior of the various complex and sometimes mysterious phenomena involved in arc formation, such as cathode spots, electrode vaporization, and near-electrode plasma formation. The book takes the reader from a model of dense cathode plasma based on charge-exchange ion-atom collisions through a kinetic approach to cathode vaporization and on to metal thermophysical properties of cathodes. This picture is further enhanced by an in-depth study of cathode jets and plasma acceleration, the effects of magnetic fields on cathode spot behavior, and electrical characteristics of arcs and cathode spot dynamics. The book also describes applications to space propulsion, thin film deposition, laser plasma generation, and magnetohydrodynamics, making this comprehensive and up-to-date volume a valuable resource for researchers in academia and industry.
Publisher: Springer Nature
ISBN: 3030447472
Category : Science
Languages : en
Pages : 1137
Book Description
This book is devoted to a thorough investigation of the physics and applications of the vacuum arc – a highly-ionized metallic plasma source used in a number of applications – with emphasis on cathode spot phenomena and plasma formation. The goal is to understand the origins and behavior of the various complex and sometimes mysterious phenomena involved in arc formation, such as cathode spots, electrode vaporization, and near-electrode plasma formation. The book takes the reader from a model of dense cathode plasma based on charge-exchange ion-atom collisions through a kinetic approach to cathode vaporization and on to metal thermophysical properties of cathodes. This picture is further enhanced by an in-depth study of cathode jets and plasma acceleration, the effects of magnetic fields on cathode spot behavior, and electrical characteristics of arcs and cathode spot dynamics. The book also describes applications to space propulsion, thin film deposition, laser plasma generation, and magnetohydrodynamics, making this comprehensive and up-to-date volume a valuable resource for researchers in academia and industry.
Handbook of Vacuum Arc Science & Technology
Author: Raymond L. Boxman
Publisher: William Andrew
ISBN: 0815517793
Category : Technology & Engineering
Languages : en
Pages : 775
Book Description
This is a comprehensive text describing the basic physics and technological applications of vacuum arcs. Part I describes basic physics of the vacuum arc, beginning with a brief tutorial review of plasma and electrical discharge physics, then describes the arc ignition process, cathode and anode spots which serve as the locus for plasma generation, and resultant interelectrode plasma. Part II describes the applications of the vacuum arc for depositing thin films and coatings, refining metals, switching high power, and as sources of intense electron, ion, plasma, and x-ray beams.
Publisher: William Andrew
ISBN: 0815517793
Category : Technology & Engineering
Languages : en
Pages : 775
Book Description
This is a comprehensive text describing the basic physics and technological applications of vacuum arcs. Part I describes basic physics of the vacuum arc, beginning with a brief tutorial review of plasma and electrical discharge physics, then describes the arc ignition process, cathode and anode spots which serve as the locus for plasma generation, and resultant interelectrode plasma. Part II describes the applications of the vacuum arc for depositing thin films and coatings, refining metals, switching high power, and as sources of intense electron, ion, plasma, and x-ray beams.
Arc Physics
Author: M.F. Hoyaux
Publisher: Springer Science & Business Media
ISBN: 3642856527
Category : Science
Languages : en
Pages : 312
Book Description
On first acquaintance the electric arc discharge appears to be both visually attractive and a relatively simple phenomena to understand. To those of us engaged in prolonged study of this discharge, it remains a constantly exciting phenomena but we become only too aware of its complex nature and the difficulties in interpreting its bulk properties. This is particu larly true when the arc exists in a practical device and is subjected therefore to extreme conditions. In recent years the possibilities for the beginning of a fuller understanding of the complexities of the arc has arisen out of the excellent research and development work of scientists and engineers throughout the world. Much of this work has been stimulated not only by the need for the development of practical devices but also by the interest in thermonuclear fusion, mag netohydrodynamic generation and space exploration. In much of this work, the arc discharge has been a common feature as a source of study of high temperature plasma. As a result of this increased interest in the arc, the expert and would-be expert is now faced with the problem of assessing extensive newly published information on arc properties. Thus there is the need for texts which present to the engineer and researcher a review and summary of the present situation. This book is a valuable contribution to this task.
Publisher: Springer Science & Business Media
ISBN: 3642856527
Category : Science
Languages : en
Pages : 312
Book Description
On first acquaintance the electric arc discharge appears to be both visually attractive and a relatively simple phenomena to understand. To those of us engaged in prolonged study of this discharge, it remains a constantly exciting phenomena but we become only too aware of its complex nature and the difficulties in interpreting its bulk properties. This is particu larly true when the arc exists in a practical device and is subjected therefore to extreme conditions. In recent years the possibilities for the beginning of a fuller understanding of the complexities of the arc has arisen out of the excellent research and development work of scientists and engineers throughout the world. Much of this work has been stimulated not only by the need for the development of practical devices but also by the interest in thermonuclear fusion, mag netohydrodynamic generation and space exploration. In much of this work, the arc discharge has been a common feature as a source of study of high temperature plasma. As a result of this increased interest in the arc, the expert and would-be expert is now faced with the problem of assessing extensive newly published information on arc properties. Thus there is the need for texts which present to the engineer and researcher a review and summary of the present situation. This book is a valuable contribution to this task.
Sculptured Thin Films
Author: Akhlesh Lakhtakia
Publisher: SPIE Press
ISBN: 9780819456069
Category : Technology & Engineering
Languages : en
Pages : 332
Book Description
Sculptured thin films (STFs) are a class of nanoengineered materials with properties that can be designed and realized in a controllable manner using physical vapor deposition. This text, presented as a course at the SPIE Optical Science and Technology Symposium, couples detailed knowledge of thin-film morphology with the optical response characteristics of STF devices. An accompanying CD contains Mathematica programs for use with the presented formalisms. Thus, readers will learn to design and engineer STF materials and devices for future applications, particularly with optical applications. Graduate students in optics and practicing optical engineers will find the text valuable, as well as those interested in emerging nanotechnologies for optical devices.
Publisher: SPIE Press
ISBN: 9780819456069
Category : Technology & Engineering
Languages : en
Pages : 332
Book Description
Sculptured thin films (STFs) are a class of nanoengineered materials with properties that can be designed and realized in a controllable manner using physical vapor deposition. This text, presented as a course at the SPIE Optical Science and Technology Symposium, couples detailed knowledge of thin-film morphology with the optical response characteristics of STF devices. An accompanying CD contains Mathematica programs for use with the presented formalisms. Thus, readers will learn to design and engineer STF materials and devices for future applications, particularly with optical applications. Graduate students in optics and practicing optical engineers will find the text valuable, as well as those interested in emerging nanotechnologies for optical devices.
Handbook of Surfaces and Interfaces of Materials, Five-Volume Set
Author: Hari Singh Nalwa
Publisher: Elsevier
ISBN: 0080533825
Category : Technology & Engineering
Languages : en
Pages : 1915
Book Description
This handbook brings together, under a single cover, all aspects of the chemistry, physics, and engineering of surfaces and interfaces of materials currently studied in academic and industrial research. It covers different experimental and theoretical aspects of surfaces and interfaces, their physical properties, and spectroscopic techniques that have been applied to a wide class of inorganic, organic, polymer, and biological materials. The diversified technological areas of surface science reflect the explosion of scientific information on surfaces and interfaces of materials and their spectroscopic characterization. The large volume of experimental data on chemistry, physics, and engineering aspects of materials surfaces and interfaces remains scattered in so many different periodicals, therefore this handbook compilation is needed.The information presented in this multivolume reference draws on two decades of pioneering research on the surfaces and interfaces of materials to offer a complete perspective on the topic. These five volumes-Surface and Interface Phenomena; Surface Characterization and Properties; Nanostructures, Micelles, and Colloids; Thin Films and Layers; Biointerfaces and Applications-provide multidisciplinary review chapters and summarize the current status of the field covering important scientific and technological developments made over past decades in surfaces and interfaces of materials and spectroscopic techniques with contributions from internationally recognized experts from all over the world. Fully cross-referenced, this book has clear, precise, and wide appeal as an essential reference source long due for the scientific community. The complete reference on the topic of surfaces and interfaces of materialsThe information presented in this multivolume reference draws on two decades of pioneering researchProvides multidisciplinary review chapters and summarizes the current status of the fieldCovers important scientific and technological developments made over past decades in surfaces and interfaces of materials and spectroscopic techniquesContributions from internationally recognized experts from all over the world
Publisher: Elsevier
ISBN: 0080533825
Category : Technology & Engineering
Languages : en
Pages : 1915
Book Description
This handbook brings together, under a single cover, all aspects of the chemistry, physics, and engineering of surfaces and interfaces of materials currently studied in academic and industrial research. It covers different experimental and theoretical aspects of surfaces and interfaces, their physical properties, and spectroscopic techniques that have been applied to a wide class of inorganic, organic, polymer, and biological materials. The diversified technological areas of surface science reflect the explosion of scientific information on surfaces and interfaces of materials and their spectroscopic characterization. The large volume of experimental data on chemistry, physics, and engineering aspects of materials surfaces and interfaces remains scattered in so many different periodicals, therefore this handbook compilation is needed.The information presented in this multivolume reference draws on two decades of pioneering research on the surfaces and interfaces of materials to offer a complete perspective on the topic. These five volumes-Surface and Interface Phenomena; Surface Characterization and Properties; Nanostructures, Micelles, and Colloids; Thin Films and Layers; Biointerfaces and Applications-provide multidisciplinary review chapters and summarize the current status of the field covering important scientific and technological developments made over past decades in surfaces and interfaces of materials and spectroscopic techniques with contributions from internationally recognized experts from all over the world. Fully cross-referenced, this book has clear, precise, and wide appeal as an essential reference source long due for the scientific community. The complete reference on the topic of surfaces and interfaces of materialsThe information presented in this multivolume reference draws on two decades of pioneering researchProvides multidisciplinary review chapters and summarizes the current status of the fieldCovers important scientific and technological developments made over past decades in surfaces and interfaces of materials and spectroscopic techniquesContributions from internationally recognized experts from all over the world
Metallurgical Coatings and Thin Films 1992
Author: G.E. McGuire
Publisher: Elsevier
ISBN: 0444596887
Category : Technology & Engineering
Languages : en
Pages : 638
Book Description
One of the increasingly important requirements for high technology materials is that they possess near-surface properties different to their bulk properties. Specific surface properties are generally achieved through the use of these films or coatings or by modifying the structure or composition of the near surface. This two-volume work contains 157 papers covering a wide range of topics involving films, coatings, and modified surfaces. All aspects of the development of deposition technologies are addressed including basic research, applied research, applications development and full scale industrial production. The work will be of interest to materials scientists, physicists, electronic, chemical and mechanical engineers, and chemists.
Publisher: Elsevier
ISBN: 0444596887
Category : Technology & Engineering
Languages : en
Pages : 638
Book Description
One of the increasingly important requirements for high technology materials is that they possess near-surface properties different to their bulk properties. Specific surface properties are generally achieved through the use of these films or coatings or by modifying the structure or composition of the near surface. This two-volume work contains 157 papers covering a wide range of topics involving films, coatings, and modified surfaces. All aspects of the development of deposition technologies are addressed including basic research, applied research, applications development and full scale industrial production. The work will be of interest to materials scientists, physicists, electronic, chemical and mechanical engineers, and chemists.
Physical vapor deposition and thermal stability of hard oxide coatings
Author: Ludvig Landälv
Publisher: Linköping University Electronic Press
ISBN: 9176850889
Category :
Languages : en
Pages : 60
Book Description
The state-of-the-art tools for machining metals are primarily based on a metal-ceramic composite (WC-Co) coated with different combinations of carbide, nitride, and oxide coatings. Combinations of these coating materials are optimized to withstand specific wear conditions. Oxide coatings, mainly α-Al2O3, are especially desired because of their high hot-hardness, chemical inertness with respect to the workpiece, and their low friction. The search for possible alloy elements, which may facilitate the deposition of such oxides by means of physical vapor deposition (PVD) techniques, has been the goal of this thesis. The sought alloy should form thermodynamically stable or metastable compounds, compatible with the temperature of use in metal cutting application. This thesis deals with process development and coating characterization of such new oxide alloy thin films, focusing on the Al-V-O, Al-Cr-Si-O, and Cr-Zr-O systems. Alloying aluminum oxide with iso-valent vanadium is a candidate for forming the desired alloys. Therefore, coatings of (Al1-xVx)2O3, with x ranging from 0 to 1, were deposited with reactive sputter deposition. X-ray diffraction showed three different crystal structures depending on V-metal fraction in the coating: α-V2O3 rhombohedral structure for 100 at.% V, a defect spinel structure for the intermediate region, (63 - 42 at.% V), and a gamma-alumina-like solid solution at lower V-content, (18 and 7 at.%), were observed, the later was shifted to larger d-spacing compared to the pure γ-Al2O3 sample obtained if deposited with only Al-target. Annealing the Al-rich coatings in air resulted in formation of V2O5 crystals on the surface of the coating after annealing to 500 °C for 42 at.% V and 700 °C for 18 at.% V metal fraction respectively. The highest thermal stability was shown for pure γ-Al2O3-coating which transformed to α-Al2O3 after annealing to 1100° C. Highest hardness was observed for the Al-rich oxides, ~24 GPa. The hardness then decreases with increasing V-content, larger than 7 at.% V metal fraction. Doping the Al2O3 coating with 7 at.% V resulted in a significant surface smoothening compared to the binary oxide. The measured hardness after annealing in air decreased in conjunction with the onset of further oxidation of the coatings. This work increases the understanding of this complicated material system with respect to possible phases formed with pulsed DC magnetron sputtering deposition as well as their response to annealing in air. The inherent difficulties of depositing insulating oxide films with PVD, requiring a closed electrical circuit, makes the investigation of process stability an important part of this research. In this context, I investigated the influence of adding small amount of Si in Al-Cr cathode on the coating properties in a pulsed DC industrial cathodic arc system and the plasma characteristics, process parameters, and coating properties in a lab DC cathodic arc system. Si was chosen here due to a previous study showing improved erosion behavior of Al-Cr-Si over pure Al-Cr cathode without Si incorporation in the coating. The effect of Si in the Al-Cr cathode in the industrial cathodic arc system showed slight improvements on the cathode erosion but Si was found in all coatings where Si was added in the cathode. The Si addition promoted the formation of the B1-like metastable cubic oxide phase and the incorporation led to reduced or equal hardness values compared to the corresponding Si-free processes. The DC-arc plasma study on the same material system showed only small improvements in the cathode erosion and process stability (lower pressure and cathode voltage) when introducing 5 at.% Si in the Al70Cr30-cathode. The presence of volatile SiO species could be confirmed through plasma analysis, but the loss of Si through these species was negligible, since the coating composition matched the cathode composition also under these conditions. The positive effect of added Si on the process stability at the cathode surface, should be weighed against Si incorporation in the coating. This incorporation seems to lead to a reduction in mechanical properties in the as-deposited coatings and promote the formation of a B1-like cubic metastable oxide structure for the (Al,Cr)2O3 oxide. This formation may or may not be beneficial for the final application since literature indicates a slight stabilization of the metastable phase upon Si-incorporation, contrary to the effect of Cr, which stabilizes the α-phase. The thermal stability of alloys for metal cutting application is crucial for their use. Previous studies on another alloy system, Cr-Zr-O, had shown solid solution, for Cr-rich compositions in that material system, in the sought corundum structure. The thermal stability of α-Cr0.28Zr0.10O0.61 coating deposited by reactive radio frequency (RF)-magnetron sputtering at 500 °C was therefore investigated here after annealing in vacuum up to 870 °C. The annealed samples showed transformation of α-(Cr,Zr)2O3 and amorphous ZrOx-rich areas into tetragonal ZrO2 and bcc-Cr. The instability of the α-(Cr,Zr)2O3 is surprising and possibly related to the annealing being done under vacuum, facilitating the loss of oxygen. Further in situ synchrotron XRD annealing studies on the α-Cr0.28Zr0.10O0.61 coating in air and in vacuum showed increased stability for the air annealed sample up to at least 975 °C, accompanied with a slight increase in ex-situ measured nanohardness. The onset temperature for formation of tetragonal ZrO2 was similar to that for isothermally vacuum annealing. The synchrotron-vacuum annealed coating again decomposed into bcc-Cr and t-ZrO2, with an addition of monoclinic–ZrO2 due to grain growth. The stabilization of the room temperature metastable tetragonal ZrO2 phase, due to surface energy effects present with small grains sizes, may prove to be useful for metal cutting applications. The observed phase segregation of α-(Cr,Zr)2O3 and formation of tetragonal ZrO2 with corresponding increase in hardness for this pseudobinary oxide system also opens up design routes for pseudobinary oxides with tunable microstructural and mechanical properties.
Publisher: Linköping University Electronic Press
ISBN: 9176850889
Category :
Languages : en
Pages : 60
Book Description
The state-of-the-art tools for machining metals are primarily based on a metal-ceramic composite (WC-Co) coated with different combinations of carbide, nitride, and oxide coatings. Combinations of these coating materials are optimized to withstand specific wear conditions. Oxide coatings, mainly α-Al2O3, are especially desired because of their high hot-hardness, chemical inertness with respect to the workpiece, and their low friction. The search for possible alloy elements, which may facilitate the deposition of such oxides by means of physical vapor deposition (PVD) techniques, has been the goal of this thesis. The sought alloy should form thermodynamically stable or metastable compounds, compatible with the temperature of use in metal cutting application. This thesis deals with process development and coating characterization of such new oxide alloy thin films, focusing on the Al-V-O, Al-Cr-Si-O, and Cr-Zr-O systems. Alloying aluminum oxide with iso-valent vanadium is a candidate for forming the desired alloys. Therefore, coatings of (Al1-xVx)2O3, with x ranging from 0 to 1, were deposited with reactive sputter deposition. X-ray diffraction showed three different crystal structures depending on V-metal fraction in the coating: α-V2O3 rhombohedral structure for 100 at.% V, a defect spinel structure for the intermediate region, (63 - 42 at.% V), and a gamma-alumina-like solid solution at lower V-content, (18 and 7 at.%), were observed, the later was shifted to larger d-spacing compared to the pure γ-Al2O3 sample obtained if deposited with only Al-target. Annealing the Al-rich coatings in air resulted in formation of V2O5 crystals on the surface of the coating after annealing to 500 °C for 42 at.% V and 700 °C for 18 at.% V metal fraction respectively. The highest thermal stability was shown for pure γ-Al2O3-coating which transformed to α-Al2O3 after annealing to 1100° C. Highest hardness was observed for the Al-rich oxides, ~24 GPa. The hardness then decreases with increasing V-content, larger than 7 at.% V metal fraction. Doping the Al2O3 coating with 7 at.% V resulted in a significant surface smoothening compared to the binary oxide. The measured hardness after annealing in air decreased in conjunction with the onset of further oxidation of the coatings. This work increases the understanding of this complicated material system with respect to possible phases formed with pulsed DC magnetron sputtering deposition as well as their response to annealing in air. The inherent difficulties of depositing insulating oxide films with PVD, requiring a closed electrical circuit, makes the investigation of process stability an important part of this research. In this context, I investigated the influence of adding small amount of Si in Al-Cr cathode on the coating properties in a pulsed DC industrial cathodic arc system and the plasma characteristics, process parameters, and coating properties in a lab DC cathodic arc system. Si was chosen here due to a previous study showing improved erosion behavior of Al-Cr-Si over pure Al-Cr cathode without Si incorporation in the coating. The effect of Si in the Al-Cr cathode in the industrial cathodic arc system showed slight improvements on the cathode erosion but Si was found in all coatings where Si was added in the cathode. The Si addition promoted the formation of the B1-like metastable cubic oxide phase and the incorporation led to reduced or equal hardness values compared to the corresponding Si-free processes. The DC-arc plasma study on the same material system showed only small improvements in the cathode erosion and process stability (lower pressure and cathode voltage) when introducing 5 at.% Si in the Al70Cr30-cathode. The presence of volatile SiO species could be confirmed through plasma analysis, but the loss of Si through these species was negligible, since the coating composition matched the cathode composition also under these conditions. The positive effect of added Si on the process stability at the cathode surface, should be weighed against Si incorporation in the coating. This incorporation seems to lead to a reduction in mechanical properties in the as-deposited coatings and promote the formation of a B1-like cubic metastable oxide structure for the (Al,Cr)2O3 oxide. This formation may or may not be beneficial for the final application since literature indicates a slight stabilization of the metastable phase upon Si-incorporation, contrary to the effect of Cr, which stabilizes the α-phase. The thermal stability of alloys for metal cutting application is crucial for their use. Previous studies on another alloy system, Cr-Zr-O, had shown solid solution, for Cr-rich compositions in that material system, in the sought corundum structure. The thermal stability of α-Cr0.28Zr0.10O0.61 coating deposited by reactive radio frequency (RF)-magnetron sputtering at 500 °C was therefore investigated here after annealing in vacuum up to 870 °C. The annealed samples showed transformation of α-(Cr,Zr)2O3 and amorphous ZrOx-rich areas into tetragonal ZrO2 and bcc-Cr. The instability of the α-(Cr,Zr)2O3 is surprising and possibly related to the annealing being done under vacuum, facilitating the loss of oxygen. Further in situ synchrotron XRD annealing studies on the α-Cr0.28Zr0.10O0.61 coating in air and in vacuum showed increased stability for the air annealed sample up to at least 975 °C, accompanied with a slight increase in ex-situ measured nanohardness. The onset temperature for formation of tetragonal ZrO2 was similar to that for isothermally vacuum annealing. The synchrotron-vacuum annealed coating again decomposed into bcc-Cr and t-ZrO2, with an addition of monoclinic–ZrO2 due to grain growth. The stabilization of the room temperature metastable tetragonal ZrO2 phase, due to surface energy effects present with small grains sizes, may prove to be useful for metal cutting applications. The observed phase segregation of α-(Cr,Zr)2O3 and formation of tetragonal ZrO2 with corresponding increase in hardness for this pseudobinary oxide system also opens up design routes for pseudobinary oxides with tunable microstructural and mechanical properties.
Medical Coatings and Deposition Technologies
Author: David Glocker
Publisher: John Wiley & Sons
ISBN: 1119310512
Category : Technology & Engineering
Languages : en
Pages : 637
Book Description
Medical Coatings and Deposition Technologies is an important new addition to the libraries of medical device designers and manufacturers. Coatings enable the properties of the surface of a device to be controlled independently from the underlying bulk properties; they are often critical to the performance of the device and their use is rapidly growing. This book provides an introduction to many of the most important types of coatings used on modern medical devices as well as descriptions of the techniques by which they are applied and methods for testing their efficacy. Developers of new medical devices and those responsible for producing them will find it an important reference when deciding if a particular functionality can be provided by a coating and what limitations may apply in a given application. Written as a practical guide and containing many specific coating examples and a large number of references for further reading, the book will also be useful to students in materials science & engineering with an interest in medical devices. Chapters on antimicrobial coatings as well as coatings for biocompatibility, drug delivery, radiopacity and hardness are supported by chapters describing key liquid coating processes, plasma-based processes and chemical vapor deposition. Many types of coatings can be applied by more than one technique and the reader will learn the tradeoffs given the relevant design, manufacturing and economic constraints. The chapter on regulatory considerations provides important perspectives regarding the marketing of these coatings and medical devices.
Publisher: John Wiley & Sons
ISBN: 1119310512
Category : Technology & Engineering
Languages : en
Pages : 637
Book Description
Medical Coatings and Deposition Technologies is an important new addition to the libraries of medical device designers and manufacturers. Coatings enable the properties of the surface of a device to be controlled independently from the underlying bulk properties; they are often critical to the performance of the device and their use is rapidly growing. This book provides an introduction to many of the most important types of coatings used on modern medical devices as well as descriptions of the techniques by which they are applied and methods for testing their efficacy. Developers of new medical devices and those responsible for producing them will find it an important reference when deciding if a particular functionality can be provided by a coating and what limitations may apply in a given application. Written as a practical guide and containing many specific coating examples and a large number of references for further reading, the book will also be useful to students in materials science & engineering with an interest in medical devices. Chapters on antimicrobial coatings as well as coatings for biocompatibility, drug delivery, radiopacity and hardness are supported by chapters describing key liquid coating processes, plasma-based processes and chemical vapor deposition. Many types of coatings can be applied by more than one technique and the reader will learn the tradeoffs given the relevant design, manufacturing and economic constraints. The chapter on regulatory considerations provides important perspectives regarding the marketing of these coatings and medical devices.