Phase composition and structure of composite Ti/HA coatings synthesized by detonation spraying

Rakhadilov, Bauyrzhan; Baizhan, Daryn; Sagdoldina, Zhuldyz; Буйткенов, Д.Б.; Maulet, M.

doi:10.1063/5.0029754

Cited by 10 publications

(9 citation statements)

References 8 publications

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“…Thus, the anatase phase is formed earlier than rutile. With an increase in the applied voltage and current density, the temperature rises, and anatase is converted to rutile at 1461 °C, which is a more stable TiO 2 phase at high temperatures [16]. Diffraction patterns of coatings obtained in various electrolytes are shown in Figure 5.…”

Section: Resultsmentioning

confidence: 99%

Research of regimes of applying coats by the method of plasma electrolytic oxidation on Ti-6Al-4V

Rakhadilov¹,

Baizhan²,

Sagdoldina³

et al. 2022

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In this work, ceramic coatings were formed on Ti6Al4V titanium alloy using a technique of plasma electrolytic oxidation. Plasma electrolytic oxidation was carried out in electrolytes with different chemical compositions and the effect of the electrolyte on the macro-and microstructure, pore size, phase composition and wear resistance of coatings was estimated. Three types of electrolytes based on sodium compounds were used, including phosphate, hydroxide, and silicate. The composition of the electrolyte affects the intensity and size of microcharges and the volume of gas release of various electrolytes. The plasma electrolytic oxidation processes were carried out at a fixed voltage (270 V) for 5 minutes. The results showed that the coating was mainly composed of rutile- and anatase TiO2 , but a homogeneous structure with lower porosity and a large number of crystalline anatase phases was obtained in the coating prepared in the silicate-based electrolyte. The diffractogram electrolytes did not reveal the peaks of the crystalline phases associated with the PO4 3— and SiO3 2— anions. This means that these anions included only oxygen in the coatings. The morphology and phase composition of the samples were studied using a scanning electron microscope and an X-ray diffractometer, respectively. Wear resistance was evaluated by the “ball-disc” method on the TRB3 tribometer. The wear resistance of various coatings formed on Ti6Al4V titanium alloys showed completely different wear resistance. The lowest coefficient of friction (µ = 0.3) was demonstrated by the coating obtained based on phosphate. This may be due to a large number of crystal phases of rutile. The sample prepared in a hydroxide-based electrolyte showed a high wear coefficient (µ=0.52). This effect can be obtained by eliminating surface defects (microcracks and micropores).

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Section: Resultsmentioning

confidence: 99%

Research of regimes of applying coats by the method of plasma electrolytic oxidation on Ti-6Al-4V

Rakhadilov¹,

Baizhan²,

Sagdoldina³

et al. 2022

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“…The coating was obtained on the CCDS 2000 detonation unit [14][15]. Oxygen-acetylene mixtures of O 2 /C 2 H 2 = 1.856 were used as explosive gas and nitrogen as a carrier gas.…”

Section: Methodsmentioning

confidence: 99%

Influence of the content of aluminum on the structure of gradient detonation coatings based on NiCr-Al

Maulet¹,

Sagdoldina²,

Rakhadilov³

et al. 2022

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This paper studies the effects of aluminium content in the composite powder on the structure of detonation gradient coatings based on NiCr-Al. Gradient coatings were obtained by detonation spraying with a gradual stepwise decrease in the barrel filling volume with an acetylene-oxygen gas mixture from 50% to 25%. The elemental and phase composition, microstructure and surface roughness of coatings based on NiCr-Al with different aluminium content of 15%, 20%, and 30% were investigated. By varying the aluminium content in the powder composition, coatings with a gradient structure were obtained. The study results showed that the phase composition of the gradient coating strongly depends on the mass fraction of Al. In the case of an aluminium content of 30% in the composition of the composite powder, the formation of aluminium oxide was detected. It is established that under the same detonation deposition modes, the formation of the gradient structure of coatings will strongly depend on the aluminium content in the NiCr-Al composition. The study results showed that the optimal composition of the powder is NiCr – 80% and Al – 20% to obtain NiCr-Al coatings with a gradient structure.

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“…This can lead to undesirable overheating or melting of the particles and a significant substrate temperature increase, which is a major limitation of this method. Pulsed energy sources like detonation spraying, which uses the energy of an explosion of gas mixtures as a pulse source, are best suited for obtaining functional-gradient coatings [16]. This technology, which operates in pulsed mode, is better for obtaining functional-gradient coatings.…”

Section: Introductionmentioning

confidence: 99%

“…Functional-gradient materials are peculiar and promising composite materials whose composition/components and/or microstructure gradually change in space according to a given profile or sequence, along one or more space directions [10,[16][17][18][19]. Due to the gradual change in composition and/or microstructure, the physical and mechanical properties change in space according to the specific requirements for the prescribed application, which improves the operational characteristics of the material.…”

Section: Introductionmentioning

confidence: 99%

Obtaining functional-gradient Ti-HA coatings by detonation spraying

Sagdoldina¹,

Baizhan²,

Kambarov³

et al. 2022

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Functional-gradient titanium/hydroxyapatite (TiHA) coatings were obtained using detonation spraying technology to improve the structure and mechanical properties. To obtain functional-gradient coatings, pulsed energy sources are best suited, namely, detonation spraying, in which the energy of the explosion of gas mixtures is used as a source of pulsed action. By controlling the modes of detonation spraying, it is possible to vary the temperature and rate of coating deposition; accordingly, it is possible to obtain a certain structuralphase structure of the coatings. The structural-phase state and tribological properties of TiHA detonation coatings were investigated by modern materials science methods: X-ray phase analysis (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX-mapping), profilometry and ball-disk wear-resistance test. The results showed that the coatings had a continuously gradient elemental composition across the cross-section of the coatings with no boundary between the elemental layers of the coatings. The amount of Ti gradually decreased and the amount of hydroxyapatite gradually increased in the direction from the substrate to the surface of the coatings, which allows to expand the possibilities of using TiHA-coatings for bone implants. Since the surface layer is composed of HA, the resulting functional-gradient coating demonstrates excellent biocompatibility and the ability to create new bone tissue. The excellent mechanical strength of the functionally graded coatings is ensured by the Ti phase.

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Phase composition and structure of composite Ti/HA coatings synthesized by detonation spraying

Cited by 10 publications

References 8 publications

Research of regimes of applying coats by the method of plasma electrolytic oxidation on Ti-6Al-4V

Research of regimes of applying coats by the method of plasma electrolytic oxidation on Ti-6Al-4V

Influence of the content of aluminum on the structure of gradient detonation coatings based on NiCr-Al

Obtaining functional-gradient Ti-HA coatings by detonation spraying

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