a-C(:H) and a-CNx(:H) films deposited by magnetron sputtering and PACVD

Nobili, Luca Giampaolo; Cavallotti, Pietro Luigi; Lecis, G. Coccia; Ponti, G.; Lenardi, Cristina

doi:10.1016/s0040-6090(97)00552-x

Cited by 12 publications

(4 citation statements)

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“…Films about 1 m thick were deposited on widia (sintered WC-8%Co) substrates, previously polished and smoothed. A detailed description of the deposition apparatus can be found in references [20,23]. As a result of the deposition process an amorphous hydrogenated and fluorinated carbon film is formed.…”

Section: Methodsmentioning

confidence: 99%

Elemental distribution in fluorinated amorphous carbon thin films

Lamperti

Bottani

Ossi

2005

J. Am. Soc. Mass Spectrom.

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Focused ion beam-secondary ion mass spectrometry (FIB-SIMS) with 20 nm spatial resolution has been used to analyze amorphous fluorinated carbon thin films, deposited by plasma assisted chemical vapor deposition (PACVD), at micro-to nano-scale. Mass spectra and ion imaging of film surface were acquired and the presence and distribution of contaminants were investigated. Surface images show the secondary ion distribution for F Ϫ , CH Ϫ , CF Ϫ . A change in size and topology of fluorine-rich areas is correlated with film hardness and with microstructure transition from diamond-like to polymer-like, as indicated by infrared and Raman spectroscopies. Based on the surface distributions of CF Ϫ and CH Ϫ and on the vibrational spectroscopy results, a mechanism of fluorine substitution for hydrogen and an attempt to explain the film structure and microstructure is proposed. . The physical properties of the ϪCF x groups, which are a film constituent, permit a considerable reduction in friction and a substantial improvement in wear resistance, and confer a hydrophobic behavior to the film surface. Electronic applications of such a material are also foreseen because of the low value of the dielectric constant k [5][6][7][8][9][10][11][12][13][14].Several material properties (structural, chemical, mechanical, electrical, optical, etc.) have been studied as functions of process parameters [4, 12, 14 -20], but a direct visualization of the surface element distribution is still lacking. We obtained a chemical surface image to reveal elements distributions, including contaminants and non-uniform elemental concentration. Such data can be used in conjunction with the other surface analysis results to gain a complete understanding of the film chemistry and structure.We analyzed two samples, representative of a set of deposited films, synthesized by PACVD, starting from C 2 H 2 and CF 4 , with different CF 4 content in the plasma atmosphere, namely 33 and 71.4% of the total gas influx; the films have different micro-structure and hardness, as deduced from previous analyses [19,20]. In particular, vibrational spectroscopies [19] enabled determination of the amorphous nature of the films, the fraction of sp 2 and sp 3 coordinated carbon atoms in the network and the presence of specific groups, specifically ϪCF x . The features of Raman spectra were also correlated with film hardness, which was measured by micro-indentation [20]. Infrared and Raman spectroscopies clearly showed the formation of a partially hydrogenated fluorocarbon film, evolving from diamond-like to polymer-like behavior as the fluorine content increases in the gas mixture.Focused ion beam secondary ions mass spectrometry (FIB-SIMS) is a unique technique for the visualization of the surface element distribution with high sensitivity and high resolution. It consists of a finely focused primary ion beam that scans and erodes a selected area on the sample surface. During the sputtering process, neutrals and secondary ions of the elements from the surface are ejected. The...

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Section: Methodsmentioning

confidence: 99%

Elemental distribution in fluorinated amorphous carbon thin films

Lamperti

Bottani

Ossi

2005

J. Am. Soc. Mass Spectrom.

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“…2 SEM photograph pertaining to a Ti-CN-a:C film in the film body, which decrease hard tetrahedral sp 3 -C bonding [39,40] and thus help the development of graphitized carbon [41] and also graphitic a:C layer at the upper surface of the film. Besides, some researchers [15,42] have mentioned that N has a reducer effect on hardness for DLC films. Voevodin et al [43] have also reported that the combination of multi-layer and functionally gradient approaches in the design of wear-protective coatings produces exceptionally tough wear-protective coatings for engineering applications, but this design approach may result in a decreased coating hardness.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Ti-CN-a: C films prepared by pulsed-dc bias sputtering

Bülbül

Efeoğlu

2010

Proceedings of the Institution of Mechanical Engineers, Part J:

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The incapable side of diamond-like carbon films is low adhesion, resulting from high internal stress. The incorporation of buffer layers into the coating structure to relieve stress and to allow crack energy dissipation by plastic deformation in the crack tip is an effective route for improving toughness. Although this approach will result in a partly decreased coating hardness, the gain in tribological properties is more preferred for many applications. In graded coatings, design and joining of the functional regions including sharp interfaces between layers are very important. The desirable properties can provide only through appropriate transition regions produced by using appropriate deposition methods. In this study, Ti-CN-a:C films were deposited on AISI M2 steel substrates by closed-field unbalanced magnetron sputtering using pulsed-dc biasing, and hardness, crystallography, wear, and adhesion properties of the film were investigated. Accordingly, Ti-CN-a:C films grown exhibited an increase of about 30 per cent in hardness according to that of the substrate and low (μ ∼ 0.1) and stable friction and good adhesion (L c = 43 N), whereas the crystallographic development of the film was amorphous. These properties obtained were attributed to using of CN transient layer and pulsed-dc magnetron sputtering technology.

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“…The deposition process has been fully described elsewhere. 9 The coatings under investigation are listed in Table 1. Al 2 O 3 balls (F99.7 Friatec) of 10 mm diameter and with a polished surface were used as counterbodies.…”

Section: Experimental: Materialsmentioning

confidence: 99%

“…The tribological performance of the steel can be improved by depositing Ti-based coatings and DLC on top of this. 9 …”

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confidence: 99%

Tribological characterisation of hard coatings with and without DLC top layer in fretting tests

Klaffke

2005

Tribotest

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The potential of coatings to protect components against wear and to reduce friction has led to a large variety of protective coatings. In order to check the success of coating modifications and to find solutions for different purposes, initial tests with laboratory tribometers are usually done to give information about the performance of a coating.Different Ti-based coatings (TiN, Ti(C,N), and TiAlN) and NiP were tested in comparison to coatings with an additional diamond-like carbon (DLC) top coating. Tests were done in laboratory air at room temperature with oscillating sliding (gross slip fretting) with a ball-on-disc arrangement against a ceramic ball (Al 2 O 3 ). Special attention was paid to possible effects of moisture (relative humidity). The coefficient of friction was measured on line, and the volumetric wear at the disc was determined after the test from microscopic measurements of the wear scar and additional profiles.The friction and wear behaviour is quite different for the different coatings and depends more or less on the relative humidity. The DLC coating on top of the other coatings reduces friction and wear considerably. In normal and in moist air the coefficient of wear of the DLC top-layer coating is significantly less than 10 −6 mm 3 /Nm and the coefficient of friction is below 0.1. In dry air, however, there is a certain tendency to high wear and high friction.

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a-C(:H) and a-CNx(:H) films deposited by magnetron sputtering and PACVD

Cited by 12 publications

References 10 publications

Elemental distribution in fluorinated amorphous carbon thin films

Elemental distribution in fluorinated amorphous carbon thin films

Characterization of Ti-CN-a: C films prepared by pulsed-dc bias sputtering

Tribological characterisation of hard coatings with and without DLC top layer in fretting tests

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