Relationship between mechanical properties of thin nitride-based films and their behaviour in nano-scratch tests

Beake, Ben D.; Vishnyakov, Vladimir; Harris, Adrian

doi:10.1016/j.triboint.2010.12.002

Cited by 89 publications

(64 citation statements)

References 48 publications

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“…Increasing ion assistance during deposition decreases hardness and stiffness of the films in agreement with our previous report that ion assistance produces softer TiFeN films when accompanied by compositional changes [7,44]. Adding iron into TiN films can either lead to inclusions of Fe or FeNx clusters [46].…”

Section: Discussionsupporting

confidence: 91%

“…In dry sliding and abrasive contact wear resistance has been found to correlate more closely with H/E than with hardness alone [1][2]. The dimensionless ratio H/E is a measure of the elastic strain to break and is strongly correlated with energy dissipation in mechanical contact and can easily be obtained in a nanoindentation test from H/Er (where Er is the reduced indentation modulus) [4][5][6][7]. In a nanoindentation test the parameter H/Er is correlated (i) with the indentation plasticity index which is the plastic or irreversible work done during indentation (Wp) divided by the total elastic (We) and plastic work done during the indentation and (ii) with hr/hmax where hr = residual indentation depth and hmax = maximum indentation depth with the relationship taking the form Plasticity index = Wp/(Wp + We)  hr/hmax  1 -x(H/Er) [1] 3…”

Section: Introductionmentioning

confidence: 99%

“…We have previously reported that a-C [41], TiFeN [7] and nc-TiN/a-SiNx [32] films deposited on silicon with high hardness can perform poorly in nano-scratch tests showing significant delamination extending far from the scratch track. However, in these previous studies it was not possible to fully determine the relationship between mechanical properties and scratch behaviour due to the limited number of samples tested.…”

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confidence: 99%

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Nano-scratch testing of (Ti,Fe)N x thin films on silicon

Beake

Vishnyakov

Harris

2017

Surface and Coatings Technology

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Thin films of (Ti,Fe)Nx have been produced on silicon wafers with a wide range of compositions and mechanical properties to investigate correlations between the mechanical properties measured by indentation and crack resistance in the highly loaded sliding contact in a nano-scratch test. The nano-scratch test data on the thin films using a well-worn Berkovich indenter with ~1 m end radius were supported by high resolution scanning electron microscopic (SEM) imaging and analytical stress modelling. The results show that mechanical properties of the coating, its thickness and the substrate properties all influence the deformation process. They affect the critical loads required, the type of failures observed and their location relative to the moving probe. The differences in coating mechanical properties affect how the interface is weakened (i.e. by initial substrate or coating yielding or both) and determine the deformation failure mechanism. The load dependence of the friction coefficient provides details of the sliding contact zone and the location of failure relative to the sliding probe. Improved performance was achieved at intermediate hardness and H 3 /E 2 in the nano-scratch tests on thin films. The friction and modelling results strongly suggest that failure at low load on the hardest coatings is due to a combination of high tensile stress at the 2 rear of the contact zone and substrate yield. Designing thin films for protective coatings with in-built dissipative structures (such as soft and low elastic modulus inclusions) and mechanisms to combat stress may be a more successful route to optimise their toughness in highly loaded sliding conditions than aiming to minimise plasticity by increasing their hardness.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Nano-scratch testing of (Ti,Fe)N x thin films on silicon

Beake

Vishnyakov

Harris

2017

Surface and Coatings Technology

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“…This combination of properties is referred to as toughness, a measure of the resistance of a material to crack formation. Several thin-film toughening approaches have been developed, including the incorporation of ductile phases, [11][12][13] multilayer structures, 14,15 compressive stresses, 16,17 phase transformations, 18,19 and carbon-nanotubes. [20][21][22] However, these approaches, which are based on methods applied to bulk materials, raise significant problems in coatings.…”

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confidence: 99%

Toughness enhancement in hard ceramic thin films by alloy design

Kindlund¹,

Sangiovanni²,

et al. 2013

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Hardness is an essential property for a wide range of applications. However, hardness alone, typically accompanied by brittleness, is not sufficient to prevent failure in ceramic films exposed to high stresses. Using VN as a model system, we demonstrate with experiment and density functional theory (DFT) that refractory VMoN alloys exhibit not only enhanced hardness, but dramatically increased ductility. V0.5Mo0.5N hardness is 25% higher than that of VN. In addition, while nanoindented VN, as well as TiN reference samples, suffer from severe cracking typical of brittle ceramics, V0.5Mo0.5N films do not crack. Instead, they exhibit material pile-up around nanoindents, characteristic of plastic flow in ductile materials. Moreover, the wear resistance of V0.5Mo0.5N is considerably higher than that of VN. DFT results show that tuning the occupancy of d–t2g metallic bonding states in VMoN facilitates dislocation glide, and hence enhances toughness, via the formation of stronger metal/metal bonds along the slip direction and weaker metal/N bonds across the slip plane

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“…Nevertheless, other geometries such as Berkovich [51] and cube corner have been used [52]. The latter combines a small end radius with high acuity and contact strain and so it particularly suited to the scratch testing of very thin films.…”

Section: Influence Of Probe Radius and Geometrymentioning

confidence: 99%