M. Tech. Department of Chemical and Metallurgical Engineering. / Aims to understand and study the tribology and tribocorrosion behaviour of the adaptive titanium-nickel-zirconia composite coatings deposited on AISI 316 stainless steel using laser surface deposition technique under various laser processing speeds. The research aim is meant to be achieved through the following objectives: 1. Determine appropriate procedure for laser feedstock deposition ; 2. Investigate tribological performance of laser composites under various loads ; 3. Evaluate the corrosion of the laser composites coatings. and 4. Assess tribocorrosion behavior of the composite coatings

Thesis (PhD) - Swinburne University of Technology, School of Engineering and Science, 2008. / A thesis submitted for the degree of Doctor of Philosophy, School of Engineering and Science, Swinburne University of Technology, 2008. Typescript. Includes bibliographical references (p. 189-204).

Thesis (Ph.D.)--Flinders University, Dept. of Chemistry. / Typescript bound. Includes bibliographical references. Also available online.

Orientador: Célia Marina de Alvarenga Freire / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-21T02:18:10Z (GMT). No. of bitstreams: 1 Pelici_BiancadeOliveira_M.pdf: 3905161 bytes, checksum: 85a5220db551a3df1468acd995cba296 (MD5) Previous issue date: 2012 / Resumo: As latas em folha-de-flandres representam a maior parte das embalagens metálicas para conservas alimentícias. Como não são inertes, durante o período de estocagem, ocorre interação com o produto e alguma dissolução de metais pode acontecer, principalmente quando se acondiciona alimentos ácidos. Para minimizar essa interação faz-se uso de revestimentos orgânicos, sendo a resina epóxi-fenólica a mais utilizada. Uma vez que os alimentos são sistemas bioquímicos complexos, na maioria dos estudos relacionados à interação produto/embalagem utiliza-se simulantes, que são substâncias orgânicas com propriedades difusivas análogas aos de um alimento e que apresentam composição química mais simples. Essas substâncias são utilizadas nos ensaios em substituição ao alimento, visando facilitar, agilizar e reduzir custos de procedimentos analíticos. A escolha do simulante é feita de acordo com as características físicoquímicas do alimento, que segue a classificação determinada pela legislação. No caso de alimentos aquosos ácidos o simulante proposto é o ácido acético 3% (m/v). Este trabalho teve por objetivo avaliar soluções simulantes alternativas ao ácido acético, realizando análises quanto ao desempenho de latas com camada nominal de estanho 2,0 g/m2 revestidas com verniz do tipo epóxi-fenólico (dupla camada interna) quando em contato com estas soluções. A técnica de espectroscopia de impedância eletroquímica foi utilizada para monitorar a degradação do revestimento orgânico e para caracterizar suas propriedades de barreira ao longo do tempo quanto a resistência à corrosão; a polarização foi aplicada para determinar a taxa de corrosão e a susceptibilidade do material metálico à corrosão. Também foram obtidas imagens da superfície das amostras através da Microscopia Eletrônica de Varredura e da Espectroscopia de Energia Dispersiva (MEV/EDS) após os ensaios eletroquímicos para complementar a caracterização do filme / Abstract: Tin-plate cans represent most of the cans for canned food. Since they are not inert, during the storage period, interaction occurs with the product and metal dissolution can occur, especially when it is acid food. To minimize this interaction it is used organic coatings, and epoxy-phenolic resin is the the most used. As the foods are complex biochemical systems, in most of the studies related to the interaction product / package simulants are used, that are organic substances that are analogous to the diffusive properties of food and have simpler composition. These substances are used in the tests to replace the food, to facilitate, speed up and reduce costs in analytical procedures. The choice of simulating is made according to the physico-chemical properties of the food, which follows the classification determined by the legislation. For acidic aqueous food the proposed simulant is acetic acid 3% (w / v). This work aimed to evaluate alternative solutions to acetic acid simulating, analyzing the performance in cans with nominal layer of tin 2.0 g/m2 coated with lacquer-type epoxy phenolic (double inner layer) when in contact with these solutions . The technique of electrochemical impedance spectroscopy was used to monitor the degradation of organic coating and to characterize their barrier properties over time as corrosion resistance; polarization was applied to determine the corrosion rate and susceptibility to corrosion of metallic material. Also images were also obtained of the sample surfaces by Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM / EDS) after the electrochemical tests to complement the characterization of the film / Mestrado / Materiais e Processos de Fabricação / Mestra em Engenharia Mecânica

Research has focused on the influences of flowing fluid on the corrosion of bare metals, but there is little emphasis on the degradation of metal-protective coating. Evaluating the metal-protective coating usually uses the Electrochemical Impedance Spectroscopy (EIS) method. This paper presents a new impedance-based wireless sensor network for metal-protective coating evaluation. This wireless sensor network consists of two parts: impedance-based wireless sensor nodes and a wireless data base that are equipped with a network analyzer (AD5933) and a RF transceiver (CC1111/CC1110). In the experiment, three coating panels are immersed in flowing deionized water (DI water) and one coating panel immersed in stationary DI water. Experimental results demonstrate that this wireless sensor network is capable of evaluating the coating degradation.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The aerospace- and automotive industries have an urgency to save space and reduce weight, as well as a need to increase fuel efficiency and reduce emissions. This has led to the use of lightweight structural materials, such as Ti6A14V alloy, which is the most widely used titanium alloy in the aerospace industry. This alloy has an exceptional strength-to-density ratio. The work also covers studies on tool steel 40CrMnMo7 that is used in applications in the tooling-, aerospace and automotive industry. In the quest for improved performance new alternative methods of efficiently machining these materials are investigated. One of the important criteria during machining of these materials is their machinability. This study discusses current research in high performance machining strategies and techniques for advanced materials such as Ti6Al4V and 40CrMnMo7. The properties that make these materials advantageous for the use in the aerospace- and automotive industry also make them difficult to cut. The widespread application of Ti6Al4V in the aerospace industry has encouraged investigations into cooling strategies or -techniques to maintain and improve tool life. Ti6Al4V has a low thermal conductivity causing the heat generated during machining to accumulate on the cutting edge of the tool. During various experiments the application of external compressed air blow cooling (dry cutting), flood cooling, high pressure through spindle cooling (HPTSC) and modifications thereof were investigated. The research project also evaluated the performance of a coating (TiAlN) and various coating treatments. The objectives of the HPTSC modifications were to improve the coolant stream impingement on the tool surface, effectively compressing the thermal barrier, and to reduce the chip-tool contact area. This would lead to a decrease in tool heating and wear. The modified techniques failed to increase tool life but showed signs of increased heat removal capability under the given conditions. It was observed that air blow cooling (dry cutting) delivered the best results when considering cutting materials, coating, coating treatment and cooling strategies or –techniques throughout the experiments conducted. / AFRIKAANSE OPSOMMING: Die Ruimte-en motor-industrie het 'n dringendheid om ruimte te bespaar en gewig te verminder, sowel as 'n behoefte om brandstofdoeltreffendheid te verbeter en emissies te verminder. Dit het gelei tot die gebruik van liggewig strukturele materiale, soos Ti6A14V Allooi , wat die mees gebruikte titanium allooi in die Ruimte is. Hierdie allooi het 'n uitsonderlike krag-tot-digtheid-verhouding. Die studie dek ook gereedskapstaal 40CrMnMo7 wat in die gereedskap, Ruimte-en motor-industrie aangewend word. In die soeke na verbeterde prestasie word nuwe alternatiewe metodes om effektief bewerking van hierdie materiaal ondersoek. Een van die belangrikste kriteria tydens bewerking van hierdie materiaal is die bewerkbaar daarvan. Hierdie studie bespreek die huidige navorsing in hoë prestasie bewerking strategieë en tegnieke vir gevorderde materiale, soos Ti6Al4V en 40CrMnMo7. Die eienskappe wat hierdie materiaal voordelig maak vir die gebruik in die lug-en Ruimte-en motor-industrie, maak dit terselfdetyd moeilik om te sny. Die wydverspreide toepassing van Ti6Al4V in die lug-en Ruimte industrie moedig ondersoeke aan na koelstrategieë of -tegnieke om die instrumentlewe te handhaaf en te verbeter. Ti6Al4V het lae termiese geleidingsvermoë wat veroorsaak dat die hitte, wat gegenereer word tydens bewerking, versamel op die voorpunt van die instrument. Tydens verskillende eksperimente was die toepassing van eksterne saamgeperste lugblaas-verkoeling (droë sny), vloed verkoeling, hoë-druk-deur-die-spil-afkoeling (HPTSC) en aanpassings daarvan geondersoek. Die navorsingsprojek het ook die prestasie van 'n bedekkingslaag (TiAlN) en verskeie bedekkingslaagbehandelings geëvalueer. Die doelwit van die HPTSC aanpassing was om die koelmiddelstroom beklemming op die instrument oppervlak te verbeter, en effektiewelik die termiese versperring saam te pers, asook die skerf-teenoorinstrument kontak te verminder. Dit sou lei tot 'n afname in die instrumentverwarming en -slytasie. Die gewysigde tegnieke het daarin misluk om die instrumentlewe te verhoog, maar het tekens getoon van 'n toename in hitte verwydering vermoë onder die gegewe omstandighede. Dit is dus waargeneem dat lugblaasverkoeling (droë sny) die beste resultate gelewer het in die oorweging van sny materiale, bedekkingslaag, bedekkingslaagbehandelings en verkoeling strategieë of -tegnieke wat regdeur die eksperimente uitgevoer was.

Orientador: Rodnei Bertazzoli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-13T22:40:42Z (GMT). No. of bitstreams: 1 Machado_CarlosHenriquedeCampos_M.pdf: 20350934 bytes, checksum: 9d0ed15edcf31e375ad6d36587a7ca3f (MD5) Previous issue date: 2009 / Resumo: o processo de deposição das ligas de zinco vem encontrando aplicações cada vez maiores na indústria de galvanoplastia, especificamente na produção de auto peças destinadas às empresas montadoras de veículos. Neste trabalho, o processo de deposição da liga Zn-Co foi estudado através da técnica de voltametria cíclica para kientificar as regiões de potenciais para a deposição dos constituintes da liga. A seguir, foram simuladas variações composicionais e operacionais do eletrólito para deposição da liga Zn-Co, normalmente observadas em linhas de produção. Adicionalmente, além das variações do eletrólito, foram estudadas amostras de peças (ferro fundido nodular como substrato) obtidas em condições adversas de processamento. O objeti,vo foi estudar a influência desses parâmetros na composição final do depósito, e na resistência à corrosão através de ensaios acelerados em câmara de névoa salina. O processo para deposição da líga Zn-Co apresentou boa estabilidade e', baixa sensibilidade às variações de concentração que podem ocorrer no cotidiano de uma linha de produção. Os ensaios em célula de Hull mostraram que variações deliberadas de 2 g.L-1 a 8 g.L-1 de Co (II) no banho produzem depósitos com 0,6 % a 1,6 % de Co na liga. Na faixa recomendada de trabalho de 4 g.L-1 a 6 g.L-1. obtém-se 0,9 % a 1,2 %. Os ensaios acelerados de corrosão em câmara de névoa salina mostraram que, mesmo nas condições mais improváveis de funcionamento, onde o teor de cobalto pode cair para 0,6 %, a camada resiste a mais de 500 horas de ensaio. Tempo de ensaio de 720 horas foi obtido quando [Zn(II)]=46 g.L-1 e [Co(II)]=4,6 g.L-1. ou seja, [Zn(II)]/[Co(II)]=10 / Abstract: Zinc alloy coatings have found large application in the metal finishing índustry, particularly for coatíng automotive parts. In thís work, the deposítíon of Zn-Co process was characterízed by cyclic voltammetry in order to identify the rangCe of deposition potential of the alloy and its constituents. Then, variations of deposition parameters and bath composition were símulated in order to study their influence on the coating properties. In addition, beside plating variation, samples produced under qnideal process condítion were studied. The plating bath presented good stability and low sensibility to variations usually observed in the industrial production. Hull-cell, experiments shown that, despite the deliberated changes in bath composítion, ,cobalt concentration in the alloy is always wíthín the range of 0,6 % to 1,6 %. Recommended values are from 0,9 % to 1,2 %. Salt spray tests shown that the Zn-Co coating lasted 500 h of test and, in the optimum deposition conditions, 720 h was obtained / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

Orientador: Amauri Hassui / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-21T02:22:26Z (GMT). No. of bitstreams: 1 Aguiar_HerbertCesarGoncalvesde_M.pdf: 11222250 bytes, checksum: a22406ca3de132e13522314dd3490816 (MD5) Previous issue date: 2012 / Resumo: Os aços inoxidáveis superduplex são materiais de estrutura bifásica contendo ferrita e austenita, que garantem ao material boa resistência à corrosão por pitting, resistência mecânica e outras características que tornam o material atrativo para as indústrias: petrolífera, óleo/gás, papel/ celulose e química. As mesmas características que tornam o aço inoxidável superduplex mais resistente dificultam a sua usinagem. Portanto, a definição dos parâmetros de usinagem deve atender ao compromisso de por um lado garantir alta produtividade e por outro não comprometer as características do material na sua aplicação. O presente trabalho consiste no torneamento com lubrificação do aço inoxidável superduplex, variando os parâmetros de usinagem e utilizando ferramentas de metal duro da classe M05-M20 revestidas com TiN/Al2O3/TiCN, Al2O3/TiCN e TiAlN, com o objetivo de investigar os efeitos dos parâmetros de usinagem sobre o mecanismo de desgaste da ferramenta através de micrografias obtidas por microscopia eletrônica de varredura (MEV) e de micro-análise semi-quantitativa através do sistema de espectroscopia de energia dispersiva (EDS), a tensão residual induzida no material usinado medida por difração raio-X e a rugosidade na peça. As análises do desgaste da ferramenta mostraram a predominância do mecanismo de adesão/attrition com surgimento de entalhe causado pelo martelamento da rebarba gerada no cavaco durante o torneamento. Isso por sua vez contribuiu ainda mais com a adesão dificultando a remoção do material que aumentou os esforços de corte gerando tensões residuais superficiais compressivas. A ferramenta revestida com TiN/Al2O3/TiCN se destacou por apresentar melhor resultado em termos de vida da ferramenta e menores tensões residuais superficiais de tração no início de vida da ferramenta em relação às ferramentas revestidas com TiAlN e Al2O3/TiCN. A condição de vc = 80 m/min e f = 0,4 mm/rev se destacou dentre todas as classes testadas em termos de produtividade. No entanto, o f = 0,4 mm/rev é prejudicial à integridade superficial gerando tensões trativas e maiores rugosidades / Abstract: The super duplex stainless steels are materials of biphasic structure containing ferrite and austenite, which guarantee a good pitting corrosion resistance, mechanical resistance and other characteristics that make the material attractive to industries: petroleum, oil/gas, paper/cellulose and chemical. The same characteristics that make the super duplex stainless steel more resistant make its machining more difficult. Therefore, the definition of machining parameters should comply with the commitment on the one hand of guaranteeing high productivity and on the other of not compromising the characteristics of the material in its application. This work consists on the turning with lubrication of the super duplex stainless steel, varying the machining parameters and using carbide tools of the grade M05-M20 coated with TiN/Al2O3/TiCN, TiAlN and Al2O3/TiCN, with the objective of investigating the effects of the machining parameters over the tools wear mechanism was also analyzed through micrographs obtained by scanning electron microscopy (SEM) and by semi-quantitative micro-analysis through the system energy dispersive spectroscopy (EDS), the residual stress induced into machined material measured by X-ray diffraction and the parts roughness. The tool wear analysis showed a predominance of the adherence/attrition mechanism with the appearance of grooves caused by the hammering of the burr generated in the chip during the turning. This, in its turn, contributed even more with the adhesion, making it difficult to remove the material which increased the effort in cutting, generating superficial compressive residual stress. The tool coated with TiN/Al2O3/TiCN highlighted itself for presenting better result in terms of the life of the tool and lower surface residual stresses of tensile at the beginning of tool life in relation to the tools coated with TiAlN and Al2O3/TiCN. The condition of vc = 80 m/min and f = 0,4 mm/rev highlighted itself among all the tested classes in terms of productivity. However, the f = 0,4 mm/rev is prejudicial to the superficial integrity, generating tensile stress and greater roughness / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

With the amalgamation of hard coating in cutting tools industries for three decades now, a stage with proven performance has been reached. Today, nearly 40% of all cutting tools used in machining applications are sheltered with coatings. Coatings have proven to dramatically improve wear resistance, increase tool life and enable use at higher speed. Over the years TiN, TiAlN and TiC have emerged as potential materials to coat machining tools. Chemical vapor deposition was the first technology to be used to deposit these coatings followed by physical vapor deposition. Currently, extensive use is being made of cathodic arc evaporation and sputtering for coatings components. The principal limiting factor in the performance of these cutting tools lies in their failure due to the brittleness of these coatings. These hard coatings, usually coated on soft steel substrates, are subjected to contact damage during service. This contact damage is driven by mismatch strain between the elastically deforming film on a plastically deforming substrate. Understanding of the contact damage is the key parameter for improvement in the coating design. Contact damage involves initiation of cracks and subsequent propagation within coating. Multiple cracking modes are seen in nitride coatings on soft substrate and mutual interaction of cracks may lead to spallation of the coating, exposing the substrate to extreme service conditions. Hence visualization of subsurface crack trajectories facilitates the classification of benign and catastrophic modes of failure, which consequently allows us to tailor the coating architecture to eliminate catastrophic failure. Multilayers have shown to perform better then monolayer coatings. In multilayer coatings, application specific particular properties can be engineered by alternately stack-ing suitable layers. The multilayer utilizes benefits of interfaces by crack deflection, crack blunting and desirable transition in residual stress across the interface. Hence, designing interfaces is the key parameter in the multilayer coating. However, very few studies exist that describe experimental visualization of deformation modes in multilayer coatings with different types of interfaces, e.g. nitride/nitride and nitride/metal. Thus the prime objective of the present study is to comprehend the influence of different interface structures as well as its architecture on the various contact damage modes in these coatings. TiAlN/TiN has shown better tribological properties compared to its constituent monolayers. There is an order of magnitude augmentation in loads for cracking without any hardness enhancement relative to monolayers of constituents, with the additional feature that both constituents exhibit similar hardness and modulus. The resistance to cracking is seen to increase with increase in number of interfaces. Hence this uniqueness in toughening without drastic reduction in mechanical properties provides the motivation for understanding the fundamental mechanisms of toughening provided by the interfaces in these hard/hard coatings. Another combination for the present study is with interfaces between hard-soft phases ZrN/Zr, a composite that seeks to compromise hardness in order to achieve greater toughness. The selected combination has potential of providing a model system without any substoichiometric nitrides influencing the interfacial structure. There is a great need to optimize the metal fraction/thickness for exploiting the benefits of toughening without much compromise on hardness and stiffness, since the principal applications of these coatings lies in preventing erosive and corrosive wear. As all the deformation modes in theses coatings are stress driven, the influence of different variables on stress field would dictate the emerging damage. To understand the role of stress fields on contact damage, finite element method and an analytical model was used to predict the stress field within the coating. The TiAlN/TiN coatings were deposited by cathodic arc evaporation, while sputtering was employed to procure the ZrN/Zr multilayer coatings with much finer layer spacing. Microstructural characterization of the as received coatings was done by XRD, scanning electron microscopy, focused ion beam cross section machining and transmission electron microscopy. Mechanical properties like hardness and modulus were evaluated by nanoindentation with restricted penetration depths to allow measurements that were not influenced by the substrate. Contact damage was induced by micro indentation at high loads. Indentations were examined from plan view as well as cross section for getting details of crack nucleation as well as propagation trajectories. Focused ion beam was used to examine cross sections of indents as well as to prepare electron transparent thin foils for transmission electron microscopy examination of subsurface damage induced by indentation. To emphasize specific issues in detail, the present work is divided into four sections: 1 Microstructure and mechanical characterization of the as deposited coatings of ZrN/Zr multilayer (while that of TiAlN/TiN has been reported elsewhere) 2 Details of contact damage in ZrN/Zr coating 3 Resolution of micro mechanistic issues in TiAlN/TiN coating utilizing detailed microscopy 4 The effect of change in architecture through heat-treatment of ZrN/Zr multilayer coatings on the mechanical behavior and contact damage Detailed microstructural, compositional and mechanical characterization was done on ZrN/Zr as received multilayer coatings. Thickness of metal layer was seen to influence the texture in the nitride, thick metal acquiring basal texture in turn inducing (111) texture in the nitride to reduce interfacial energy. Microstructure revealed that the nitride grows with interrupted columnar grains, renucleating at each metal/nitride interface. Presence of both phases was confirmed at even very low bilayer spacing, with slight changes in multilayers architecture, from planar interfaces to curved interfaces. The chosen system proved to be an ideal system for multilayer study without formation of secondary nitrides. Residual stress and hardness reduced with increase in metal layer thickness, whereas modulus was seen to follow the rule of mixture value. Detailed contact damage study of ZrN/Zr is reported in section two with influence of volume fraction and metal layer thickness. All the experimental results were corroborated with finite element methods. A comparative study of contact damage of multilayer with monolayer was carried out with cross section as well as plan view of indents. Metal plasticity was able to distribute damage laterally as well as vertically, hence reducing the stress concentration. There lies an optimum thickness of the metal providing maximum toughening by increasing the threshold load required for edge cracking. The sliding of columns is resisted by the metal. However, thick metal layers promote microcracking in individual nitride layers. Cracking is restricted to within individual nitride layers, eliminating through thickness cracking. The intermediate metal thickness was able to provide a mechanism of laterally distributing sliding and hence a higher tolerance level of the indentation strain that can be accommodated without cracking. Thin metal multilayers were seen to show delamination, strongly influenced by the multilayer architecture. We use the finite element method to understand the influence of stress fields in driving these various modes of damage for varying volume fraction and metal layer thicknesses. It is demonstrated how metal plasticity results in stress enhancement in the nitride layer compared to a monolayer and reduces the shear stress, which is the driving force for columnar sliding. The micro cracking to columnar shearing transition with metal thickness was explained with the help of average shear and normal stress across the multilayer which could explain the transition from cracking and sliding to interfacial delamination in thin metal layer multilayers with enhancement in interfacial shear stress. TiAlN/TiN multilayer allowed to exploit a form of compositional contrast to measure the strain with respect to depth. Layers acting as strain markers quantify the amount of sliding in terms of the offset in layers with respect to depth within the coating. We illustrate with transmission electron micrographs, the flaw generation that occurs as a result of sliding of misaligned column boundaries. These boundary kinks,upon further loading, may lead to cracks running at an angle to the indentation axis in an otherwise dense, defect free, as deposited coating. A previous study illustrates the increase in resistance of multilayers to multiple modes of cracking that are seen in the monolayer nitride coatings on steel substrates. We provide evidence of the enhanced plasticity, seen as macroscopic bending, which in reality is column sliding in a series of distributed small steps. We discuss the role of misfit dislocations in spreading the material laterally to accommodate the constraints during indentation and lattice bending. Interfacial sliding is seen to reduce the stress concentration by distributing the vertical column sliding and accommodating the flaws generated by the sliding of misaligned column boundaries. Some preferred boundaries with special orientation relations do slide, while near the substrate, the sliding is facilitated by the relaxation in intrinsic residual stresses. An analytical model which was formulated earlier is used to support our experimental findings. Investigations of the plausible reasons for the naturally occurring multilayer mollusc sea shells to reach stiffnesses equal to the upper bound of the rule of mixture value have concluded that its brick and mortar organization is responsible for its exceptional mechanical properties. Inspired by the same model, heat treatment was used to change the architecture of the soft-hard metal/nitride combination from that of the planar interface of the as deposited multilayer to a brick and mortar arrangement. Such an interconnected ZrN microstructure was successfully achieved and the stiffness and hardness were both seen to increase relative to the as received coatings. The possible reasons for this enhancement are discussed in term of this newly emerged architecture ,change in residual stress as well as changes in stoichiometry after heat treatment. The contact damage, though, was found to be more catastrophic relative to the as deposited coating with increased propensities for edge and lateral cracking. This was attributed to the interconnected nitrides formed in the brick and mortar architecture as well as residual stress changes due to the dissolution of Zr in ZrN to form off-stoichiometric nitrides. The cracks feel the presence of the metal and deviate from the otherwise smooth trajectory and take a path along the interface of the metal packet and the interconnected nitride. Summarizing, the present study clearly illustrates the fact that interfaces play an important role in damage control under contact loading. Fracture and deformation are either controlled by metal plasticity, distributing the column sliding in metal/nitride multilayers or by interfacial sliding mediated by interfacial misfit dislocations in case of the nitride/nitride multilayer coatings. The effective role of interfaces is to distribute damage laterally as well as horizontally to relieve stresses and hence enhance the damage tolerance under indentation. Optimum metal layer thickness has been proposed for maximum toughening in the metal/nitride multilayer coating and the role of interfaces in providing modes of plasticity is presented for the nitride/nitride multilayer coatings by use of extensive transmission electron microscopic investigations. A new interconnected architecture coatings provides a unique way of combining stiffness and toughness along with scope for further developing such configurations with improved mechanical properties.