Mechanical And Thermal Stability Of Hard Nitride Coatings

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Mechanical And Thermal Stability Of Hard Nitride Coatings

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Author : Yu-Hsiang Chen
language : en
Publisher: Linköping University Electronic Press
Release Date : 2018-05-15

Mechanical And Thermal Stability Of Hard Nitride Coatings written by Yu-Hsiang Chen and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-05-15 with categories.

Hard coating’s thermal stability is essential due to the high temperature environment of high-speed cutting applications, while the phase and microstructure evolution induced by exposing the coating to high temperature affects the mechanical properties. In this thesis, the mechanical stability of arc-evaporated, hard, transition metal nitride coatings annealed at high temperature is analyzed and related to the phase and microstructure evolution. In addition to hardness, fracture toughness is evaluated by surface and cross-sectional investigations by scanning/transmission electron microscopy of damage events following mechanical tests. The crack resistance of Ti1?xAlxN with a range of Al content (x = 0.23-0.82) was studied by contact fatigue tests, where the differences in the microstructure were found to play a major role. Superior mechanical properties were found in Ti0.63Al0.37N; in the as-deposited state as a result of a favorable grain size, and after annealing at 900o C due to the microstructure formed during spinodal decomposition. The mechanical and high-temperature properties of hard coatings can be enhanced by alloying or multi-layering. Within this work, quaternary Ti-Al-X-N (X = Cr, Nb and V) alloys were studied and superior toughness was found for TiAl(Nb)N in both the as-deposited and annealed (1100? C) states. The hexagonal (h)-AlN formation in cubic (c)-TixAl0.37Cr1?0.37?xN (x = 0.03 and 0.16) was analyzed by in-situ x-ray scattering during annealing. The energy for h-AlN formation was found to be dependent on the microstructure evolution during annealing, which varies with the coating composition. High Al content h-ZrAlN/c-TiN and h-ZrAlN/c-ZrN multilayers were investigated through scratch tests followed by focused ion-beam analysis of the crack propagation. A c-Ti(Zr)N phase forms in h-ZrAlN/c-TiN multilayers at high temperatures and that contributes to enhanced hardness and fracture toughness by keeping the semi-coherent sub-interfaces. Finally, an in-situ analysis of coatings by x-ray scattering during a turning process was carried out. It demonstrates the possibility of observation of stress evolution and thermal expansion of the coatings or the work piece material during machining. This experiment provides real-time information on the coating behavior during cutting. Hårda skikts högtemperaturstabilitet är viktig på grund av den höga temperaturskikten utsätts för under skärande bearbetning, och den utveckling av faser och mikrostruktur som då sker påverkar skiktets mekaniska egenskaper. I den här avhandlingen har den mekaniska stabiliteten hos arcförångade, hårda metallnitridskikt som värmebehandlats vid höga temperaturer studerats. Förutom hårdhet har även skiktens seghet utvärderats genom yt- och tvärsnittsstudier av den sprickbildning som uppstår vid mekanisk provning med hjälp av svep- och transmissionselektronmikroskopi. Segheten hos Ti1?xAlxN skikt med varierande Al-halt (x = 0.23-0.82) studerades genom utmattningsprovning och resultaten visar att förändringar i mikrostrukturen spelar en stor roll. Ti0.63Al0.37N skikten hade överlägsna mekaniska egenskaper; på grund av en fördelaktig kornstorlek i de obehandlade skikten och efter värmebehandling som ett resultat av det spinodala sönderfall som skett. De mekaniska egenskaperna och högtemperaturegenskaperna hos hårda skikt kan förbättras genom legering eller genom multilagring. I den här avhandlingen har kvarternära Ti-Al-X-N (X = Cr, Nb eller V) skikt studerats och TiAl(Nb)N skikten hade en överlägsen seghet i både obehandlat och värmebehandlat (1100oC) tillstånd. Bildandet av h-AlN i TixAl0.37Cr1?0.37?xN (x = 0.03 and 0.16) skikt studerades genom in situ röntgenspridning under värmebehandling. Den energi som krävs för att bilda h-AlN beror av mikrostrukturutvecklingen under värmebehandling vilken i sin tur beror av skiktens kemiska sammansättning. h-ZrAlN/c-TiN och h-ZrAlN/c-ZrN multilager med hög Al-halt undersöktes genom reptester följda av tvärsnittsstudier av sprickbildningen genom en analys med en fokuserad jonstråle (FIB). En c-Ti(Zr)N fas bildas vid höga temperaturer i h-ZrAlN/c-TiN multilagren och det bidrar till förhöjd hårdhet och förbättrad seghet på grund av en bibehållen koherens mellan lagren. Slutligen har in situ röntgenspridningsstudier av ytskikt utförts vid svarvning. Studien visar på möjligheten att observera spänning och värmeutvidgning av skikten eller arbetsmaterialet under bearbetning. Experimenten ger information om skiktens beteende under bearbetning i realtid. La estabilidad térmica del recubrimiento es esencial debido a que estos recubrimientos durante su aplicación son utilizados a elevada temperatura y a alta velocidad. Durante dicho proceso, la evolución microestructural afecta a las propiedades mecánicas. En dicha tesis, la estabilidad mecánica de los recubimientos duros base nitruro producidos mediante arco y recocidos a elevada temperatura son analizados y se correlacionado con su transformación de fase. La dureza, la resistencia a la fractura son evaluados mediante la observación tanto superficial como transversal mediante microscopia electrónica de barrido. La resistencia a la propagación de grieta de Ti1?xAlxN con un contenido en Al que fluctúa entre 0.23-0.82 se estudia mediante ensayos de fatiga por contacto, donde la diferencia microstructural juega un papel importante. Las mejores propiedades mecánicas se encentran en las muestras con un 0.63 de Ti donde se ha realizado un proceso de recocido a 900o C debido a la descomposición espinoidal. Las características mecánicas y de alta temperatura de recubrimientos duros pueden ser mejoradas si tenemos un recubrimiento multicapa. Aleaciones cuaternarias de Ti-Al-X-N (X = Cr, Nb y V) son estudiada, y una mejor tenacidad de fractura se encuentra para la muestra TiAl(Nb)N sin tratamiento de recocido como recocida a 1000ºC. La formación del AlN con una estructura hexagonal en la muestra TixAl0.37Cr1?0.37?xN (x = 0.03 y 0.16) son analizadas mediante ensayos in-situ de difracción de rayos X durante el proceso de recocido. Cabe mencionar que la energía cinética para la formación de la AlN con una estructura hexagonal depende del proceso de recocido, la cual hace variar la composición química del recubrimiento. Multicapas de h (hexagonal)-ZrAlN/c (cúbica)-TiN con un elevado contenido de Al son estudiadas mediante ensayos de rayado y la generación de daño es observado mediante la técnica del haz de iones focalizados. Las formas de la fase de c-Ti(Zr)N en las multicapas de (h)-ZrAlN/c-TiN formadas a elevadas temperaturas contribuyen a mejorar la dureza y la tenacidad de fractura manteniendo la semicoherencia en las intercaras entre cada capa. Finalmente, se realiza un análisis in-situ de los diferentes recubrimientos me diante dispersión de rayos X durante un proceso de torneado. En este caso, se demuestra la posibilidad de observar la evolución de las tensiones residuales y de la expansión térmica durante el proceso de conformado. Dicho experimentos proporciona información en tiempo real sobre el comportamiento del recubrimiento en condiciones de servicio.

Physical Vapor Deposition And Thermal Stability Of Hard Oxide Coatings

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Author : Ludvig Landälv
language : en
Publisher: Linköping University Electronic Press
Release Date : 2019-04-26

Physical Vapor Deposition And Thermal Stability Of Hard Oxide Coatings written by Ludvig Landälv and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-04-26 with categories.

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.

Inside The Miscibility Gap

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Author : Lars Johnson
language : en
Publisher:
Release Date : 2012

Inside The Miscibility Gap written by Lars Johnson and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.

This thesis is concerned with self-organization phenomena in hard and wear resistant transition-metal nitride coatings, both during growth and during post deposition thermal annealing. The uniting physical principle in the studied systems is the immiscibility of their constituent parts, which leads, under certain conditions, to structural variations on the nanoscale. The study of such structures is challenging, and during this work atom probe tomography (apt) was developed as a viable tool for their study. Ti0.33Al0.67N was observed to undergo spinodal decomposition upon annealing to 900 °C, by the use of apt in combination with electron microscopy. The addition of C to TiSiN was found to promote and refine the feather-like microstructure common in the system, with an ensuing decrease in thermal stability. An age-hardening of 36 % was measured in arc evaporated Zr0.44Al0.56N1.20, which was a nanocomposite of cubic, hexagonal, and amorphous phases. Magnetron sputtering of Zr0.64Al0.36N at 900 °C resulted in a self-organized and highly ordered growth of a two-dimensional two-phase labyrinthine structure of cubic ZrN and wurtzite AlN.The structure was analyzed and recovered by apt, although the ZrN phase suffered from severe trajectory aberrations, rendering only the Al signal useable.The initiation of the organized growth was found to occur by local nucleation at 5-8 nm from the substrate, before which random fluctuations in Al/Zr content increased steadily from the substrate. Finally, the decomposition of solid-solution TiB0.33N0.67 was found, by apt, to progress through the nucleation of TiB0.5N0.5 and TiN, followed by the transformation of the former into hexagonal TiB2.

Properties Of Multilayered And Multicomponent Nitride Alloys From First Principles

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Author : Fei Wang
language : en
Publisher: Linköping University Electronic Press
Release Date : 2018-02-09

Properties Of Multilayered And Multicomponent Nitride Alloys From First Principles written by Fei Wang and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-02-09 with categories.

This thesis is a theoretical exploration of properties of multilayered and multicomponent nitride alloys, in particular their mixing thermodynamics and elastic behaviors. Systematic investigation of properties of a large class of materials, such as the multicomponent nitride solid solutions, is in line with the modern approach of high-throughput search of novel materials. In this thesis we benchmark and utilize simple but efficient methodological frameworks in predicting mixing thermodynamics, Young’s moduli distribution of multilayer alloys and the linear thermal expansion of quaternary nitride solid solutions. We demonstrate by accurate ab-initio calculations that Ti1−xAlxN solid solution is stabilized by interfacial effects if it is coherently sandwiched between TiN layers along (001). For TiN/AlN and ZrN/AlN multilayers we show higher thermodynamic stability with semicoherent interfaces than with isostructural coherent ones. Accurate 0 Kelvin elastic constants of cubic TixXyAl1−x−yN (X=Zr, Hf, Nb, V, Ta) solid solutions and their multilayers are derived and an analytic comparison of strengths and ductility are presented to reveal the potential of these materials in hard coating applications. The Young’s moduli variation of the bulk materials has provided a reliable descriptor to screen the Young’s moduli of coherent multilayers. The Debye model is used to reveal the high-temperature thermodynamics and spinodal decomposition of TixNbyAl1−x−yN. We show that though the effect of vibration is large on the mixing Gibbs free energy the local spinoal decomposition tendencies are not altered. A quasi-harmonic Debye model is benchmarked against results of molecular dynamics simulations in predicting the thermal expansion coefficients of TixXyAl1−x−yN (X=Zr, Hf, Nb, V, Ta). Denna avhandling är en teoretisk undersökning av egenskaperna hos multilager och multikomponentlegeringar av nitrider, särskilt deras blandningstermodynamik och elastiska egenskaper. Systematiska undersökningar av egenskaperna hos en stor materialfamilj, såsom fasta lösningar av multikomponentnitrider, ligger i linje med den moderna angreppsvinkeln av massundersökningar i sökandet efter nya material. I denna avhandling utvärderar och använder vi enkla men effektiva metodologiska ramverk för att förutsäga blandningstermodynamik, fördelning av Young’s moduli multilager och den linjära termiska expansionen i kvaternära fasta lösningar av nitrider. Vi visar med precisa ab-initio-beräkningar att en fast lösning av Ti1−xAlxN stabiliseras av gränssnittseffekter om den placeras koherent mellan TiN-skikt längs med (001). För multilager av TiN/AlN och ZrN/AlN påvisar vi högre termodynamisk stabilitet med semikoherenta gränsskikt än med isostrukturella koherenta. Precisa elastiska konstanter vid 0 K för kubiska fasta lösningar av TixXyAl1−x−yN (X=Zr, Hf, Nb, V, Ta) och deras multilager beräknas och en analytisk jämförelse av deras hållfasthet och duktilitet presenteras för att visa dessa materials potential som hårda beläggningar. Variationen av Young’s moduli materialen i bulk har gett en pålitlig deskriptor för att undersöka Young’s moduli koherenta multilager. Debye-modellen används för att undersöka hög-temperatur-termodynamiken och spinodalt sönderfall hos TixNbyAl1−x−yN. Vi visar att trots att vibrationers effekt på Gibbs fria energi för blandning är stor påverkas inte de lokala tendenserna för spinodalt sönderfall. En kvasiharmonisk Debye-modell jämförs med resultat från molekyldynamiksimuleringar för att förutsäga utvidgningskoefficienter för TixXyAl1−x−yN (X=Zr, Hf, Nb, V, Ta). Diese Arbeit ist eine theoretische Untersuchung der Eigenschaften von mehrschichtigen und mehrkomponentigen Nitridlegierungen, insbesondere deren Mischungs- Thermodynamik und elastischen Verhalten. Eine systematische Untersuchung von Eigenschaften einer großen Klasse von Materialien, wie zum Beispiel fester Lösungen von Mehrkomponenten-Nitriden, ist im Einklang mit dem zeitgenössischen Hochdurchsatzverfahren für die Suche nach neuen Materialien. In dieser Arbeit benchmarken und nutzen wir einfache, aber effiziente methodische Frameworks zur Vorhersage der Mischungs-Thermodynamik, der Verteilung des Elastizitätsmoduls von Mehrschichtlegierungen und der linearen thermischen Ausdehnung von festen, quaternären Nitrid-Lösungen. Wir zeigen durch genaue Ab-initio-Berechnungen, dass Ti1−xAlxN Mischkristalle durch Grenzflächenwirkungen stabilisiert werden, wenn sie kohärent zwischen TiN Schichten entlang (001) sandwichartig angeordnet sind. Die genauen elastischen Konstanten von kubischen TixXyAl1−x−yN (X = Zr, Hf, Nb, V, Ta) Mischkristallen und deren Mehrfachschichten bei 0 Kelvin werden abgeleitet und ein analytischer Vergleich der Festigkeit und Duktilität zeigt das Potential dieser Materialien in Hartbeschichtungsanwendungen. Das Debye-Modell wird verwendet, um die Hochtemperatur-Thermodynamik und die spinodale Entmischung von TixNbyAl1−x−yN aufzudecken. Wir zeigen, dass sich die lokale Tendenzen zur spinodalen Entmischung nicht ändern, obwohl die Wirkung von Vibrationen auf die Gibbs-Energie großist. Ein quasi-harmonisches Debye-Modell wird gegen die Ergebnisse von Moleküldynamik-Simulationen gebenchmarkt, um die thermische Ausdehnungskoeffizienten von TixXyAl1−x−yN (X=Zr, Hf, Nb, V, Ta) vorherzusagen.

Phase Stability And Defect Structures In Ti Al N Hard Coatings

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Author : Katherine M. Calamba
language : en
Publisher: Linköping University Electronic Press
Release Date : 2019-05-27

Phase Stability And Defect Structures In Ti Al N Hard Coatings written by Katherine M. Calamba and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-05-27 with categories.

This study highlights the role of nitrogen vacancies and defect structures in engineering hard coatings with enhanced phase stability and mechanical properties for high temperature applications. Titanium aluminum nitride (Ti,Al)N based materials in the form of thin coatings has remained as an outstanding choice for protection of metal cutting tools due to its superior oxidation resistance and high-temperature wear resistance. High-temperature spinodal decomposition of metastable (Ti,Al)N into coherent c-TiN and c-AlN nm-sized domains results in high hardness at elevated temperatures. Even higher thermal input leads to transformation of c-AlN to w-AlN, which is detrimental to the mechanical properties of the coating. One mean to delay this transformation is to introduce nitrogen vacancies. In this thesis, I show that by combining a reduction of the overall N-content of the c-(Ti,Al)Ny (y < 1) coating with a low substrate bias voltage during cathodic arc deposition an even more pronounced delay of the c-AlN to w-AlN phase transformation is achieved. Under such condition, age hardening is retained until 1100 ?C, which is the highest temperature reported for (Ti,Al)N films. During cutting operations, the wear mechanism of the cathodicarc-deposited c-(Ti0.52Al0.48)Ny with N-contents of y = 0.92, 0.87, and 0.75 films are influenced by the interplay of nitrogen vacancies, microstructure, and chemical reactions with the workpiece material. The y = 0.75 coating contains the highest number of macroparticles and has an inhomogeneous microstructure after machining, which lower its flank and crater wear resistance. Age hardening of the y = 0.92 sample causes its superior flank wear resistance while the dense structure of the y = 0.87 sample prevents chemical wear that results in excellent crater wear resistance. Heteroepitaxial c-(Ti1-x,Alx)Ny (y = 0.92, 0.79, and0.67) films were grown on MgO(001) and (111) substrates using magnetron putter deposition to examine the details of their defect structures during spinodal decomposition. At 900 ?C, the films decompose to form coherent c-AlN- and c-TiN- rich domains with elongated shape along the elastically soft <001> direction. Deformation maps show that most strains occur near the interface of the segregated domains and inside the c-TiN domains. Dislocations favorably aggregate in c-TiN rather than c-AlN because the later has stronger directionality of covalent chemical bonds. At elevated temperature, the domain size of (001) and (111)- oriented c-(Ti,Al)Ny films increases with the nitrogen content. This indicates that there is a delay in coarsening due to the presence of more N vacancies in the film. The structural and functional properties (Ti1-x,Alx)Ny are also influenced by its Al content (x). TiN and (Ti1-x,Alx)Ny (y = 1, x = 0.63 and x = 0.77) thin films were grown on MgO(111) substrates using magnetron sputtering technique. Both TiN and Ti0.27Al0.63N films are single crystals with cubic structure. (Ti0.23,Al0.77)N film has epitaxial cubic structure only in the first few atomic layers then it transitions to an epitaxial wurtzite layer, with an orientation relationship of c-(Ti0.23,Al0.77)N(111)[1-10]??w-(Ti0.23,Al0.77)N(0001)[11-20]. The w-(Ti0.23,Al0.77)N shows phase separation of coherent nm-sized domains with varying chemical composition during growth. After annealing at high temperature, the domains in w-(Ti0.23,Al0.77)N have coarsened. The domains in w-(Ti0.23,Al0.77)N are smaller compared to the domains in c-(Ti0.27,Al0.63)N film that has undergone spinodal decomposition. The results that emerged from this thesis are of great importance in the cutting tool industry and also in the microelectronics industry, because the layers examined have properties that are well suited for diffusion barriers.

Nanostructured Coatings

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Author : Albano Cavaleiro
language : en
Publisher: Springer Science & Business Media
Release Date : 2007-02-19

Nanostructured Coatings written by Albano Cavaleiro and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007-02-19 with Technology & Engineering categories.

This book delivers practical insight into a broad range of fields related to hard coatings, from their deposition and characterization up to the hardening and deformation mechanisms allowing the interpretation of results. The text examines relationships between structure/microstructure and mechanical properties from fundamental concepts, through types of coatings, to characterization techniques. The authors explore the search for coatings that can satisfy the criteria for successful implementation in real mechanical applications.

Ti Al N Based Hard Coatings

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Author : Florent Uny
language : en
Publisher:
Release Date : 2019

Ti Al N Based Hard Coatings written by Florent Uny and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with Electronic books categories.

For several decades, the increasing productivity in many industrial domains has led to a significant and ever-increased interest to protective and hard coatings. In this context, titanium-aluminum nitrides were developed and are now widely used in a large range of applications, due to their high hardness, good thermal stability, and oxidation resistance. This chapter reviews the thermodynamical characteristics of the Ti-Al-N system by reporting the progress made in the description of the Ti-Al-N phase diagram and the main mechanical and chemical properties of Ti1,àíxAlxN-based coatings. As a metastable phase, the existence of the fcc-Ti1,àíxAlxN depends on particular process parameters, allowing stabilizing this desirable solid solution. The influence of process parameters, with a particular interest for chemical vapor deposition (CVD) methods, on morphology and crystallographic structure is then described. The structure of Ti1,àíxAlxN thin films depends also on the aluminum content as well as on the annealing temperature, due to the spinodal nature of the Ti-Al-N system. These changes of crystallographic structure can induce an improvement of the hardness, oxidation resistance, and wear behavior of these coatings. The main mechanical and chemical properties of physical vapor deposition (PVD) and CVD Ti1,àíxAlxN-based coatings are also described.

Theoretical And Experimental Studies Of Ternary And Quaternary Nitrides For Machining And Thermoelectric Materials

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Author : Robert Pilemalm
language : en
Publisher: Linköping University Electronic Press
Release Date : 2019-04-02

Theoretical And Experimental Studies Of Ternary And Quaternary Nitrides For Machining And Thermoelectric Materials written by Robert Pilemalm and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-04-02 with Non-Classifiable categories.

Nitrides are used as coatings and thin films for a wide range of applications. The study and use of nitrides in the recent decades have shifted towards ternary, quaternary or even higher order (complex) nitrides. There is an interest to use ternary and quaternary nitrides for machining and thermoelectric materials, because it gives the possibility to choose composition and thereby design the materials properties. This thesis presents research results on TiAlN and and TiAlN-based coatings that are used as hard coatings for machining and on ternary scandium nitrides that are of interest for thin films for thermoelectric applications. The high-pressure high-temperature behavior of cubic TiAlN deposited on cubic boron nitride has been experimentally studied. It has been shown that the spinodal decomposition, which means decomposition into cubic domains enriched in TiN and AlN, is delayed as a result of high pressure compared to ambient pressure. No chemical interaction between coating and substrate occurs. TiZrAlN has been theoretically and experimentally studied at high temperature. The results show that the when Zr-content is decreased and the Al-content is increased the decomposition route changes from nucleation and growth to spinodal decomposition. The microstructure evolution with temperature depends on the initial composition. In the case where the decompositon starts with only spinodal decomposition the microstructure at 1100 °C consists of domains that are larger than in the case where the decomposition occurs by nucleation and growth. ScMN2 (M=V, Nb, Ta) phases have been experimentally demonstrated for M=Nb and Ta in a few studies, but have not been much investigated. In this theseis, their crystal structure, stability, elastic properties, electronic structure and thermoelectric properties have been studied. At 0 K and 0 GPa it has been shown that these three phases are thermodynamically and elastically stable. Additionally, these are narrow-bandgap semiconductors and their thermoelectric properties can be tuned by doping. Pressure has a stabilizing effect on these structures. When pressure increases from 0-150 GPa the elastic constants and moduli increases in the range 53-317 %.

Coatings For High Temperature Environments

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Author : Amirhossein Pakseresht
language : en
Publisher: Springer Nature
Release Date : 2023-12-05

Coatings For High Temperature Environments written by Amirhossein Pakseresht and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-12-05 with Technology & Engineering categories.

This book addresses the recent trends in high-temperature coatings that are used to provide oxidation and wear resistance to metallic/ceramic components in extreme environments. Ceramics, intermetallics, organosilicon polymers, cermets, and other materials with great thermal stability have long been recognized for these applications. This book introduces the state of the art in coating materials and processes for high-temperature environments and identifies areas for improvement in materials selection, performance upgrades, design considerations, and manufacturing methods. The book covers a variety of high-temperature coatings prepared through various synthesis processes such as thermal spraying, physical vapor deposition, electrodeposition, and sol–gel methods. It covers corrosion/oxidation, phase stability, and thermal and mechanical behavior of high-temperature coating materials having greater thermal stability. With contributions from international researchers active in the field, this edited book features the most recent and up-to-date literature references for a broad readership consisting of academic and industrial professionals. It is suitable for graduate students as well as scientists and engineers working in the area of anti-corrosion and anti-wear resistant high-temperature coatings for industrial applications.

Novel Nanocomposite Coatings

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Author : Rostislav Daniel
language : en
Publisher: CRC Press
Release Date : 2014-12-16

Novel Nanocomposite Coatings written by Rostislav Daniel and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-12-16 with Technology & Engineering categories.

Nanocomposite materials as a special class of nanostructured materials have recently attracted great interest due to their extraordinary mechanical properties as well as thermal stability and oxidation resistance. The unique structure and exceptional properties make nanocomposite materials a possible alternative to traditional polycrystalline materials, which have met their limits in many recent engineering applications. In particular, nanocomposite coatings synthesized by plasma-assisted deposition processes under highly non-equilibrium conditions provide a high potential for new applications as protective and functional coatings in automotive, aerospace, tooling, electronic, or manufacturing industry. This book provides a comprehensive overview of the synthesis of Si-containing hard nanocomposite coatings based on transition metal nitrides by plasma-based thin film processing. It demonstrates the full versatility of these nanocomposites for low Si-containing coatings tailored with superior mechanical properties and novel high Si-containing nanocomposite coatings with extraordinary thermal stability and resistance against oxidation optimized for high-temperature applications. It pays special attention to understanding growth mechanisms of these structures under specific deposition conditions, structure–property relations, and stability of individual constituents to enhance their functionality for various applications.