The glow discharge plasma influence on the oxide layer and diffusion zone formation during process of thermal oxidation of titanium and its alloys

Januszewicz, Bartłomiej; Siniarski, D.

doi:10.1016/j.vacuum.2006.03.008

Cited by 16 publications

(16 citation statements)

References 2 publications

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“…In agreement with previous work [25,40,41], the TO treatment regime was found to be less efficient in hardening titanium compared to a plasmaassisted process. The triode plasma treatment used in this work is likely to accentuate further this discrepancy as the intensified plasma process is able to increase the generation of point defects compared to diode plasmas used elsewhere.…”

Section: Resultssupporting

confidence: 91%

“…For plasma-assisted diffusion processes, the energetic species not only create lattice defects which accelerate diffusion but also activate the surface, thereby enhancing oxide formation. Such an increase in oxide layer thickness when oxidation is performed in the presence of plasma has also been demonstrated in [25]; however, for TPO processed samples no complex oxides (Ti x O y ) were identified.…”

Section: Resultssupporting

confidence: 56%

“…Leng et al [8] used dc-plasma oxidation to synthesise oxide layers to improve the biocompatibility and wear resistance of commercially pure titanium. Januszewicz and Siniarski [25], on the other hand, used an Ar + O 2 dc-plasma glow discharge during the diffusion stage, to enhance oxygen diffusion kinetics; however, the use of a diode plasma resulted in little or no increase in the hardened layer thickness compared to thermal oxidation. Clearly, there is still ample scope for further work in order to permit the use of oxidation processes for engineering applications of titanium that involve tribological surface contacts.…”

Section: Introductionmentioning

confidence: 99%

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Surface modification of Ti–6Al–4V alloys using triode plasma oxidation treatments

Cassar

Wilson²,

Banfield

et al. 2012

Surface and Coatings Technology

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In this study, triode plasma oxidation (TPO) has been used to improve the tribological characteristics of Ti-6Al-4V. The effect of TPO on ball-on-plate reciprocating-sliding, impact, and micro-abrasion wear resistance of this alloy is investigated. Surface micro-profilometry, nano-/micro-indentation hardness testing, scratch-adhesion testing, scanning electron microscopy (SEM), atomic force microscopy (AFM), glancing-angle X-ray diffraction (GAXRD), and glow-discharge optical emission spectroscopy (GDOES) data is presented to corroborate the effects of the oxidation process. 'Traditional' thermal oxidation processes were used to benchmark this novel treatment. Following TPO treatment at 700°C for only 4 h, a hard (exceeding 11 GPa) and well-adhered oxide layer, composed of mixtures of the anatase and rutile polymorphs of TiO 2 , was formed at the surface of the Ti-alloy. This layer is accompanied by a much larger oxygen-solution strengthened zone which creates a gradual chemical and mechanical gradient from the hard oxide 'compound layer' into the ductile substrate core. The various wear testing methods employed revealed excellent wear resistance of the TPO-treated alloy-compared both to the untreated alloy and to conventional, thermally oxidised samples.

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Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

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Surface modification of Ti–6Al–4V alloys using triode plasma oxidation treatments

Cassar

Wilson²,

Banfield

et al. 2012

Surface and Coatings Technology

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“…It is well known that titanium alloys feature both a low strength and a low hardness. Load bearing capacity of the titanium alloys may be essentially improved by the deep hardening with the use of interstitial oxygen atoms . Therefore, the Ti‐6Al‐4V alloy was oxygen hardened by oxidation under plasma glow discharge in order to increase the hardness of the substrate.…”

Section: Introductionmentioning

confidence: 99%

Microstructure, mechanical and tribological properties of the nc‐Cr_xC_y/a‐C and nc‐Cr_xC_y/a‐C:H nanocomposite coatings on oxygen‐hardened Ti‐6Al‐4V alloy

Zimowski

Moskalewicz

Kot

et al. 2012

Surface & Interface Analysis

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The nanocomposite coatings, nc‐CrxCy/a‐C and nc‐CrxCy/a‐C:H, consisting of chromium carbide nanocrystals embedded in an amorphous hydrogen free carbon (a‐C) matrix or in an amorphous hydrogenated carbon (a‐C:H) matrix deposited on oxygen‐hardened Ti‐6Al‐4V alloy by magnetron sputtering were investigated. Oxygen hardening of titanium alloy was performed by oxidation under plasma glow discharge. For both coatings, the phase identification by high‐resolution transmission electron microscopy revealed the presence of Cr7C3 and Cr23C6 nanocrystals of size 2÷13 nm embedded in an amorphous carbon a‐C and a‐C:H matrix. The microhardness values were found to be 9.7 GPa and 12.1 GPa for the nc‐CrxCy/a‐C and nc‐CrxCy/a‐C:H coatings, respectively, and 10.6 GPa for oxygen‐hardened titanium alloy. Scratch tests indicated good coating‐substrate adhesion for both coatings. It was found that the hydrogenated nc‐CrxCy/a‐C:H coating exhibited lower coefficient of friction ranging from 0.1 to 0.15 (while sliding 1‐mm diameter alumina ball) as compared to friction coefficient of nc‐CrxCy/a‐C coating which showed higher value, up to 0.2. The coated alloy features much better wear resistance than oxygen‐hardened one. Copyright © 2012 John Wiley & Sons, Ltd.

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“…Borgioli has shown that, for the same treatment time, the hardened layer produced during plasma oxidation of pure titanium [10] and Ti6Al4V [11] is thicker and possesses superior mechanical properties compared to the oxide layer generated by conventional thermal oxidation processes. The marked increase in surface hardness as a result of plasma oxidation leads a reduction in the wear rate of the titanium alloy [12,13], hence improving its tribological performance.…”

Section: Introductionmentioning

confidence: 99%

An investigation into the effect of Triode Plasma Oxidation (TPO) on the tribological properties of Ti6Al4V

Banfield

Wilson²,

Cassar

et al. 2011

Surface and Coatings Technology

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Improving the tribological properties of titanium alloys has been the subject of extensive research for many years. A number of thermochemical processes have been developed for that purpose. In this study, surface hardening of Ti6Al4V is achieved by Triode Plasma Oxidation (TPO) which differs from conventional diode plasma treatments through the use of a third electrode; a negatively biased tungsten filament to enhance the ionisation levels in the plasma. The resultant surface generally consists of a top oxide layer with an oxygen diffusion zone lying immediately underneath it. The effects of process parameters such as substrate temperature, current density and oxygen partial pressure have been investigated. Surface hardness measurements at various indentation loads were carried out to assess the changes in hardness with depth across the diffusion layer. The hardness profiles obtained confirmed the gradual decrease in hardness with treatment depth and provided an indication of the thickness of the hardened layer produced. Ball-on-plate reciprocating sliding wear data and glancing angle XRD analyses of the oxidised samples are also presented. The results indicate that a harder and deeper case is achieved at both high substrate temperature and high oxygen partial pressure. Furthermore, XRD data show that the substrate temperature strongly affects the structure of the oxide layer produced. All TPO-treated samples exhibit significantly better wear performance compared to the untreated material.

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The glow discharge plasma influence on the oxide layer and diffusion zone formation during process of thermal oxidation of titanium and its alloys

Cited by 16 publications

References 2 publications

Surface modification of Ti–6Al–4V alloys using triode plasma oxidation treatments

Surface modification of Ti–6Al–4V alloys using triode plasma oxidation treatments

Microstructure, mechanical and tribological properties of the nc‐Cr_xC_y/a‐C and nc‐Cr_xC_y/a‐C:H nanocomposite coatings on oxygen‐hardened Ti‐6Al‐4V alloy

An investigation into the effect of Triode Plasma Oxidation (TPO) on the tribological properties of Ti6Al4V

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The glow discharge plasma influence on the oxide layer and diffusion zone formation during process of thermal oxidation of titanium and its alloys

Cited by 16 publications

References 2 publications

Surface modification of Ti–6Al–4V alloys using triode plasma oxidation treatments

Surface modification of Ti–6Al–4V alloys using triode plasma oxidation treatments

Microstructure, mechanical and tribological properties of the nc‐CrxCy/a‐C and nc‐CrxCy/a‐C:H nanocomposite coatings on oxygen‐hardened Ti‐6Al‐4V alloy

An investigation into the effect of Triode Plasma Oxidation (TPO) on the tribological properties of Ti6Al4V

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Microstructure, mechanical and tribological properties of the nc‐Cr_xC_y/a‐C and nc‐Cr_xC_y/a‐C:H nanocomposite coatings on oxygen‐hardened Ti‐6Al‐4V alloy