X-Ray Diffraction Characterization of Crystallinity and Phase Composition in Plasma-Sprayed Hydroxyapatite Coatings

Prevéy, Paul S.

doi:10.1361/105996300770349827

Cited by 137 publications

(61 citation statements)

References 11 publications

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“…Although the increased solubility of the APS deposited HA coatings may allow for rapid osseointegration compared with the pure HA surfaces, it is however generally associated with the formation of fibrous bone [1] rather than stable, lamellar bone observed previously for CoBlast surfaces [37]. The XRD peak broadening displayed in each of the HA coating spectra has been suggested by Prevéy to be due to the presence of nanocrystalline HA [55]. The XRD spectra for the titanium alloy substrates after acid removal of the HA layer are shown in Fig 9. The MAUD software was further utilised to examine the substrate XRD spectra, and specifically monitored for α and β phases of the metal titanium as the Ti-6Al-4V is defined as an α-β phase titanium alloy [56].…”

Section: Compositional Analysismentioning

confidence: 90%

Evaluation and comparison of hydroxyapatite coatings deposited using both thermal and non-thermal techniques

Barry

Twomey

Cowley

et al. 2013

Surface and Coatings Technology

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This paper compares the properties of hydroxyapatite (HA) coatings, obtained using two different deposition technologies on Ti-6Al-4V substrates. The deposition techniques evaluated were: atmospheric plasma spray (APS, thermal treatment) and a novel micro-blasting technique known as CoBlast (non-thermal treatment). The HA coatings were examined with respect to their morphology, crystallinity and adhesion, while the phase concentration of the metallic substrates were also analysed. In vitro cell proliferation and cell morphology studies using MG-63 osteoblastic cells were carried out on the HA coated substrates obtained using the two deposition techniques, with untreated titanium grade 5 (Ti-6Al-4V) substrates utilised as a control. XRD analysis of the CoBlast deposited HA coatings demonstrated that it was comprised of the same crystalline HA as the precursor powder. For the APS HA coatings however, additional calcium phosphate phases were observed, and these were attributed to phase changes caused by the high plasma deposition temperatures. The APS treated samples also exhibited evidence of substrate modification, with substrate conversion to a β-rich surface at the HA/substrate interface was observed in the XRD analysis. CoBlast HA coatings, with an average thickness of approx. 2.5 µm, were found to have higher tensile adhesion values (33.6 and 35.7MPa), when compared with the 5 MPa obtained for the approx. 26.9 µm thick APS coatings using a modified tensile adhesion test. This lower adhesion tensile value is most likely due to the increased residual stress generated in the HA coating during thermal plasma processing. The cell response studies on the four surfaces tested indicate that the HA surfaces exhibited higher levels of cell proliferation than the untreated titanium after 5 days, with the CoBlast surfaces displaying statically significant increases in cell proliferation.3

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Section: Compositional Analysismentioning

confidence: 90%

Evaluation and comparison of hydroxyapatite coatings deposited using both thermal and non-thermal techniques

Barry

Twomey

Cowley

et al. 2013

Surface and Coatings Technology

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“…During plasma spraying, the molten HA particles deposited on the metal substrate are quenched at a high cooling rate leading to the formation of amorphous calcium phosphate compounds and the reduction of the crystallinity of the coating. Some metastable compounds, such as calcium-deficient hydroxyapatite (CDHA), oxyhydroxyapatite (OHA), calcium oxide (CaO), a-tricalcium phosphate (a-TCP), b-tricalcium phosphate, and tetra-calcium phosphate (TTCP) have been detected in the coating [230,235]. It has been reported that the amorphous and metastable compounds are more soluble than the crystalline HA [236] thereby accelerating fixation of the implant with the bone and promoting bone remodeling and attachment [237].…”

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confidence: 99%

Surface modification of titanium, titanium alloys, and related materials for biomedical applications

Liu

Chu

Ding

2004

Materials Science and Engineering: R: Reports

3,027

1,477

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Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, in order to improve the biological, chemical, and mechanical properties, surface modification is often performed. This article reviews the various surface modification technologies pertaining to titanium and titanium alloys including mechanical treatment, thermal spraying, sol-gel, chemical and electrochemical treatment, and ion implantation from the perspective of biomedical engineering. Recent work has shown that the wear resistance, corrosion resistance, and biological properties of titanium and titanium alloys can be improved selectively using the appropriate surface treatment techniques while the desirable bulk attributes of the materials are retained. The proper surface treatment expands the use of titanium and titanium alloys in the biomedical fields. Some of the recent applications are also discussed in this paper. #

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“…Entretanto, com o aumento No entanto, como mencionado por Guerrini et al [9] , uma outra possibilidade para o cálculo da cristalinidade é o uso de difração de raios X (DRX). Para tal foi utilizado o índice de razão de intensidade (RIR) como definido por Prevéy [27] . A Tabela 3 resume os resultados obtidos.…”

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Caracterização morfológica de nanomembranas de poliamida-66 dopadas com grafeno obtidas por electrospinning

2012

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IntroduçãoDevido à elevada relação entre sua área superficial e seu volume, à interconectividade de suas fibras e à existência de espaço intertistial, as nanomembranas são de grande interesse em um grande número de aplicações onde estruturas porosas são desejáveis, tais como: compósitos estruturais, exocompósitos, nanobiotecnologia, sistemas de purificação de ar, bioengenharia, engenharia ambiental e eletrônica, e indústrias energética, de defesa e segurança [1][2][3][4][5] .Embora a técnica de fabricação de fibras sintéticas utilizando descargas elétricas tenha sido descoberta no século passado [6,7] , foi apenas recentemente que o electrospinning tornou-se alvo de um grande número de pesquisadores em todo o mundo [8,9] . O princípio operacional do processo de electrospinning é relativamente simples, tornando-o bastante vantajoso quando comparado aos demais métodos de fabricação de nanofibras [2] . Além disso, o controle dimensional das nanofibras geradas, a reprodutibilidade de resultados e o grande potencial para aplicações industriais em larga escala fizeram com que o processo de electrospinning se tornasse bastante "popular" nos últimos anos.A técnica de electrospinning envolve a aplicação de um forte campo elétrico entre o polímero e um coletor metálico [3,10,11] . Geralmente, o polímero, fundido ou em solução, está contido em um reservatório com um tubo capilar (tipicamente, uma seringa hipodérmica e uma agulha), e é forçado a escoar por uma agulha por ação da gravidade ou com o auxílio de uma bomba de infusão. Quando se aplica uma alta tensão elétrica no tubo capilar, que está localizado à uma certa distância de um coletor (que pode ser plano e estacionário ou cilíndrico e rotativo), ocorre uma polarização nas moléculas do polímero. Quando a diferença de potencial elétrico entre o tubo capilar e o coletor ultrapassa um valor crítico, a força eletrostática atuando no polímero passa a ser maior do que a tensão interfacial da solução na ponta do tubo, formando o chamado cone de Taylor e acarretando a formação de um jato que é atraído em direção ao coletor. Neste ponto, o campo elétrico é responsável por alongar o jato, tornando-o cada vez mais fino, dando origem às fibras de diâmetros micro ou nanométricos [12,13] .Para que o processo de electrospinning seja possível, é necessário que o polímero esteja fundido ou disperso em solução. Dessa forma, fica evidente que as propriedades da solução (peso molecular do polímero, viscosidade, tensão interfacial e condutividade elétrica da solução, e efeito dielétrico do solvente) irão desempenhar um papel importante no processo de geração das nanofibras. Outros fatores de grande influência Caracterização Morfológica de Nanomembranas de Poliamida-66 Dopadas com Grafeno Obtidas por Electrospinning José de Ávila Júnior Programa de Pós-graduação em Engenharia Mecânica, UFMG Antônio Ferreira Ávila Departamento de Engenharia Mecânica, UFMG Matt H. Triplett Aviation and Missile Research Development and Engineering Center, AMSRD-AMR-WD-GAResumo: Neste estudo, investigou-se a ...

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X-Ray Diffraction Characterization of Crystallinity and Phase Composition in Plasma-Sprayed Hydroxyapatite Coatings

Cited by 137 publications

References 11 publications

Evaluation and comparison of hydroxyapatite coatings deposited using both thermal and non-thermal techniques

Evaluation and comparison of hydroxyapatite coatings deposited using both thermal and non-thermal techniques

Surface modification of titanium, titanium alloys, and related materials for biomedical applications

Caracterização morfológica de nanomembranas de poliamida-66 dopadas com grafeno obtidas por electrospinning

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