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Effect of pulse laser treatment at different process variables on mechanical behavior of carbon nanotubes electrophoretically deposited on titanium alloy

Majkowska-Marzec Beata, Staszewski Kacper, Sypniewska Joanna

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 2

157--168

EN

Titanium and its alloys are widely used as biomaterials for long-term implants, but they are usually surface-modified due to their weak bioactivity and wear resistance. Laser processing was used to modify the surface layer, and elemental carbon was a component of the deposited coatings. This research aims to use a combination of both methods based on preliminary electrophoretic deposition of multi-wall carbon nanotubes (MWNCTs) followed by pulse laser treatment. Carbon nanotubes were chosen due to their mechanical and chemical stability as well as their tubular shape, resulting in enhanced mechanical properties of laser-modified layers. Methods: The pulse laser power and laser scanning speed were defined as variable process parameters. The microstructure, roughness Ra, nanohardness H, Young’s modulus E, and indent depth values were measured, and the H/E, H 3 /E2 , and relative changes of all these values in comparison to MWCNTs-coated and non-coated surfaces, were calculated. Results: The obtained results show that the best mechanical properties of MWCNTs-coated and laser-treated specimens are obtained at a laser power of 900 W and laser feed of 6 mm/s. The observed relations can be explained considering processes occurring on the surface such as deposition of carbon nanotubes, melting and re-crystallization of the surface layer, formation and possible partial decomposition of titanium carbides, and associated changes in local chemical composition, phase composition, and a level of residual stresses beneath the surface. Conclusions: The developed process can substitute the time and money-consuming carbonization of titanium and its alloys.

2

Microstructure and mechanical properties of laser surface-treated Ti13Nb13Zr alloy with MWCNTs coatings

Majkowska-Marzec Beata, Sypniewska Joanna

Advances in Materials Science

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2021

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Vol. 21, nr 4(70)

5--18

EN

Laser surface modification of titanium alloys is one of the main methods of improving the properties of titanium alloys used in implantology. This study investigates the microstructural morphology of a laser-modified surface layer on a Ti13Nb13Zr alloy with and without a carbon nanotube coating deposited by electrophoretic deposition. Laser modification was performed for samples with and without carbon nanotube coating for two different laser powers of 800 W and 900 W and for different scan rates: 3 mm/s or 6 mm/s at 25 Hz, and the pulse duration was 2.25 ms or 3.25 ms. A scanning electron microscope SEM was used to evaluate the surface structure of the modified samples. To observe the heat-affected zones of the individual samples, metallographic samples were taken and observed under an optical microscope. Surface wettability tests were performed using a goniometer. A surface roughness test using a profilograph and a nanoindentation test by NanoTest™ Vantage was also performed. Observations of the microstructure allowed to state that for higher laser powers the surfaces of the samples are more homogeneous without defects, while for lower laser powers the path of the laser beam is clearer and more regular. Examination of the microstructure of the cross-sections indicated that the samples on which the carbon nanotube coating was deposited are characterized by a wider heat affected zone, and for the samples modified at 800 W and a feed rate of 3 mm/s the widest heat affected zone is observed. The wettability tests revealed that all the samples exhibit hydrophilic surfaces and the samples with deposited carbon nanotube coating increase it further. Surface roughness testing showed a significant increase in Ra for the laser-modified samples, and the presence of carbon nanotubes further increased this value. Nanoindentation studies showed that the laser modification and the presence of carbon coating improved the mechanical properties of the samples due to their strength.

3

The influence of laser alloying of Ti13Nb13Zr on surface topography and properties

Tęczar P., Majkowska-Marzec Beata, Bartmański Michał

Advances in Materials Science

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2019

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Vol. 19, nr 1(59)

44--56

EN

The laser alloying is a continually developing surface treatment because of its significant and specific structuration of a surface. In particular, it is applied for Ti alloys, being now the most essential biomaterials` group for load-bearing implants. The present research was performed on the Ti13Nb13Zr alloy subject to laser modification in order to determine the treatment effects on surface topography and its some mechanical properties like nanohardness, Young's modulus, roughness. A pulse laser Nd:YAG was applied at three different laser pulse regimes: either 700 W, 1000 W or 1000 W treatment followed by 700 W modification at a pulse duration of 1 ms. The surface topography and morphology were examined using light microscopy and scanning electron microscopy with spectroscope of X-ray energy dispersion. The mechanical properties were determined by nanoindentation tests and surface roughness with a use of profilograph. The wettability was tested with a goniometer. The obtained results demonstrate complex behavior of the material surface: decrease in penetration distance and increase in hardness after first laser treatment, maintenance of this trend when machining using a higher laser pulse power, followed by an increase in penetration and decrease in hardness after additional laser treatment at lower power input, due to which a surface with fewer defects is obtained. The change in Young`s modulus follows the change in other mechanical properties, but not a change in roughness. Therefore, the observed hardening with the increase of the laser pulse power and then a small softening with the use of additional treatment with lower power can be attributed to some processes of remelting, diffusion and crystallization, sensitive to the previous surface state and heat energy flux. Despite that, the laser treatment always caused a significant hardening of the surface layer.

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Hydroxyapatite deposition on the laser modified Ti13Nb13Zr alloy

Jażdżewska M., Majkowska-Marzec B.

Advances in Materials Science

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2017

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Vol. 17, nr 4(54)

5--13

EN

The Ti13Nb13Zr alloy was subjected to laser modification with the Nd:YAG laser provided that such treatment would increase the surface roughness followed improved adhesion of hydroxyapatite (HAp) coatings The hydroxyapatite was deposited by electrophoretic method in suspension of 0.5 g HA powder and 100 ml ethyl alcohol. The deposition was carried out for 10 min at 10 V voltage followed by drying at room temperature for 24 h and heating at 800°C for 1 h in vacuum. The thickness of the HAp coatings was found as of about 4.06 μm to 9.05 μm. The examinations of surfaces were carried out at each stage of the experiment with the ultra-high resolution scanning electron microscope. The measurements of surface roughness after laser treatment and after HAp deposition were performed with the Hommel Etamic Waveline profilograph.

5

Electrophoretic Deposition and Characterisation of Chitosan Coatings on Near-Β Titanium Alloy

Jugowiec D., Kot M., Moskalewicz T.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2A

657--664

EN

In this study, chitosan coatings were electrophoretically deposited (EPD) on near-β Ti-13Nb-13Zr alloy. The influence of colloidal solution composition and EPD parameters on the quality of chitosan coatings was investigated. It was established that the uniformity of as-deposited chitosan coatings is highly dependent on the chemical composition of the solution used for EPD, the pH, electrophoretic mobility and zeta potential of chitosan colloidal molecules, as well as EPD parameters, such as potential difference value and deposition time. The microstructure of the coatings was investigated using electron microscopy and X-ray diffractometry. The coatings 350 nm thick were homogeneous and exhibited an amorphous structure. The coatings had low hardness and Young’s modulus. The effect of surface of the substrate preparation prior to coating deposition on the adhesion of chitosan coatings to the Ti-13Nb-13Zr alloy was also investigated. The coatings exhibited good adhesion to the non-acid-etched surface of the titanium alloy.

6

Wpływ modyfikacji laserowej stopu Ti13Nb13Zr na mikrostrukturę powłok hydroksyapatytowych

Majkowska B., Jażdżewska M., Zieliński A., Antoszkiewicz M.

Inżynieria Materiałowa

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2015

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Vol. 36, nr 3

134--137

PL

Dotychczasowe badania powierzchni wszczepów tytanowych dla chirurgii kostnej wykazały, że osteointegracja na powierzchniach rozwiniętych jest znacznie szybsza niż na powierzchniach gładkich, co za tym idzie chropowatość powierzchni implantu ma bardzo duży wpływ na adhezję składników środowiska biologicznego. W artykule przedstawiono wstępne wyniki badań dotyczące wpływu chropowatości powierzchni stopu Ti13Nb13Zr o bardzo małym module Younga na budowę wytworzonej powłoki hydroksyapatytowej. Próbki z biostopu tytanu poddano obróbce laserowej za pomocą lasera Nd:YAG firmy Trumph o średniej mocy 150 W w celu zmiany geometrii powierzchni. Na tak przygotowanym podłożu wytwarzano powłoki hydroksyapatytowe metodą elektroforezy, stosując 0,5 i 1,0 g stężenie proszku HAp na 100 ml alkoholu etylowego. Osadzanie katodowe prowadzono przy napięciu 10 i 50 V przez 5 i 10 min. Po przeprowadzonej obróbce laserowej i wytworzeniu powłok HAp mierzono profil chropowatości powierzchni i prowadzono obserwacje za pomocą skaningowego mikroskopu elektronowego.

EN

So far research of the surfaces of titanium implants in bone surgery demonstrate that osteointegration on rough surface is much faster than on smooth ones. The roughness of implant surface influences then the adhesion of components of biological environment. In this paper the preliminary research results made on the Ti13Nb13Zr alloy treated with pulse laser and coated with hydroxyapatite are presented. The aim of the research was to determine the influence of effect of laser treatment and HAp deposition parameters on structure of the hydroxyapatite coating. The laser treatment was carried with the pulse Nd:YAG laser (Trumph) of the 150 W average power in order to change the surface geometry. Next the HAp coatings were deposited by electrophoretic method using the suspension of 0.5 or 1.0 g of HAp powder in 100 ml ethanol. The deposition was made at 10 V and 50 V for 5 and 10 min. The surface roughness profiles and microscopic examinations were performed after laser treatment and HAp deposition.