A comparative study of the mechanical strength of chemical vapor-deposited diamond and physical vapor-deposited hard coatings

Kamiya, Shoji; Nagasawa, H.; Yamanobe, Kiichiro; Saka, Masumi

doi:10.1016/j.tsf.2004.05.135

Cited by 22 publications

(9 citation statements)

References 23 publications

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“…[16,32] the prenotch was machined straight down in the central part of the sample only, leaving two side walls that formed a precrack when bend-testing thin film samples of silicon oxide, nitride or oxynitride. Testing of small-scale beams containing FIB-premachined notches has been shown in several studies to give K c values near those found for macroscopic samples [15][16][17]26,27]; however, in many other studies, different results, ranging from values slightly to much higher [11,18,19,[21][22][23][24]30,33], or in some cases lower [20,34], than the toughness data from tests on macroscopic specimens of the same material were obtained with FIB-notched specimens.…”

Section: Introductionmentioning

confidence: 89%

Fracture toughness testing of nanocrystalline alumina and fused quartz using chevron-notched microbeams

et al. 2015

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We show that chevron-notched samples offer an attractive approach to the measurement of fracture toughness in micron-scale samples of brittle materials and use the method to characterize quartz and nanocrystalline alumina. Focused ion beam milling is used to carve bend bars of rectangular cross-section a few micrometres wide and containing a notch with a triangular ligament. Load-controlled testing is conducted using a nanoindentation apparatus. If the notch is appropriately machined, cracks nucleate and propagate in a stable fashion before becoming unstable. Sample dimensions are measured using a scanning electron microscope, and are used as input in finite element simulations of the bars' elastic deformation for various crack lengths. The calculated compliance calibration curve and the measured peak load then give the local fracture toughness of the material. Advantages of the method include a low sensitivity to environmental subcritical crack growth, and the fact that it measures toughness at the tip of a sharp crack situated in material unaffected by ion-milling. The approach is demonstrated on two materials, namely, monolithic fused quartz and nanocrystalline alumina Nextele 610 fibres; results for the latter give the intrinsic grain boundary toughness of alumina, free of grain bridging effects.

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Section: Introductionmentioning

confidence: 89%

Fracture toughness testing of nanocrystalline alumina and fused quartz using chevron-notched microbeams

et al. 2015

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“…[12][13][14][15] Figure 4 shows the finite element model used in the numerical simulation. [12][13][14][15] Figure 4 shows the finite element model used in the numerical simulation.…”

Section: B Numerical Simulation For Evaluating Interface Adhesionmentioning

confidence: 99%

A comparative study of a new microscale technique and conventional bending techniques for evaluating the interface adhesion strength in IC metallization systems

et al. 2010

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We developed a new microscale technique for evaluating the local interface adhesion in a thin film stack and we compared it with a conventional four-point bending technique. Using the microscale technique, the interface adhesion was estimated to be 3.0 J/m 2 by comparing experimental results with numerical simulation results for interface crack propagation behavior. The four-point bending technique was applied to the same interface and the interface adhesion was estimated to be 4.4 J/m 2 by experiment. However, this value is an overestimate because it includes the plastic deformation of epoxy resin used to fabricate the specimens. By eliminating the additional energy dissipated through plastic deformation of the epoxy resin close to the interface crack tip, the interface adhesion was evaluated to be 3.3 J/m 2 . This value agrees well with that obtained using the microscale technique.

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“…A spontaneous delamination of the coating from the substrate still prior to the beginning of the operation due to considerable compressive stresses is observed in [40], whereas in [41] it is reported about the decrease in the coating-substrate adhesion due to residual compressive stresses in the process of operation. The authors [45,46] also state that due to too high level of residual stresses, coatings become more brittle and their adhesion with the base material loosens. In [28], the beginning of the crack formation in the tool base material is related to the presence of the residual tensile stresses in the surface area of the substrate, added by tensile stresses that occur in the process of the tool operation.…”

Section: Relationship Between Residual Stresses and The Mechanical Chmentioning

confidence: 99%

Evaluation of residual stresses in PVD-coatings. Part 1. Review

Soroka

2010

Strength Mater

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We present a review of the results of investigations on residual stresses in plasma-vacuum coatings obtained by the physical vapor deposition methods. The data on the character of residual stresses and factors influencing their values and distribution are analyzed. The works are considered that investigate the effect of residual stresses on the physico-mechanical characteristics of the substratecoating system. Recommendations on the further studies of residual stresses in PVD-coatings and the improvement in their level control are presented.Keywords: vacuum plasma coatings, residual stresses, thermal and structural components of stresses, reference potential, intermediate and buffer interlayers, multilayer coating, nanostructural and nanolayer coatings, discontinuous coating. Introduction.One of the peculiar features of modified surface layers of structural materials is the occurrence of residual stresses therein. Residual stresses in functional coatings affect the performance characteristics and life of parts and tools with coatings, as well as the strength characteristics of both the coating itself and the substrate-coating system. The account of these stresses is required, since the residual stresses promote or inhibit fracture processes, depending on the sign, distribution and mode of loading. Therefore, a strong need exists to correctly estimate the level of residual stresses, to reveal the reasons for their occurrence, to establish the manufacturing factors and parameters of the surface architecture that influence their value.The use of coatings obtained by the physical vapor deposition (PVD) method that has started in the sixties of the last century, is gaining further acceptance, particularly for parts and tools operating under conditions of heavy loads and high temperatures.The goal of the work is to review published investigations involving the defining of the physical nature and value of residual stresses in PVD-coatings, the revealing of the characteristics of the coating formation process and the parameters of the surface architecture that influence these stresses, and also the establishing of the relationship between the strength and wear resistance of the substrate-coating system and the level of residual stresses. We hope that this review will make it possible to state the problems and ways for further investigations on the residual stresses in PVD-coatings and to find the methods for attaining such "useful" level of these stresses that will agree with the maximum mechanical properties.Residual Stresses in PVD-Coatings: Value and Distribution, Physical Nature, and Dependence on Manufacturing Parameters. The occurrence of residual stresses is due to different factors, such as the difference in the coefficients of thermal expansion for the substrate and coating materials; the presence of the captured atoms of gas; the condensate imperfection, etc. Assumptions on the physical nature of residual stresses in PVD-coatings are somewhat different. In [1], using the X-ray method, it was determined that res...

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A comparative study of the mechanical strength of chemical vapor-deposited diamond and physical vapor-deposited hard coatings

Cited by 22 publications

References 23 publications

Fracture toughness testing of nanocrystalline alumina and fused quartz using chevron-notched microbeams

Fracture toughness testing of nanocrystalline alumina and fused quartz using chevron-notched microbeams

A comparative study of a new microscale technique and conventional bending techniques for evaluating the interface adhesion strength in IC metallization systems

Evaluation of residual stresses in PVD-coatings. Part 1. Review

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