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Simultaneous degradation by corrosion and wear of titanium in artificial saliva containing fluorides

Souza, J.C.M; Barbosa, S. L; Ariza, E.; Celis, J-P.; Rocha, L. A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2012 ENG
Relevância na Pesquisa
37.01%
Article in press; The degradation of titanium-based oral rehabilitation systems can occur by corrosion and wear processes taking place simultaneously (tribocorrosion) and influenced by the presence of fluorides. In this study, the tribocorrosion behavior of titanium in artificial saliva solutions containing fluorides is investigated. Before sliding tests were started up, electrochemical measurements such as open circuit potential (OCP) and impedance spectroscopy (EIS) were performed to get information on the corrosion behavior of titanium in artificial saliva solutions. Then, sliding wear tests were carried out at the OCP taken by the test sample. Scanning electron microscopy and weight loss measurements were performed after the tribocorrosion tests. The presence of a compact passive surface film on titanium immersed was demonstrated in artificial saliva free of fluorides and in presence of up to 227 ppm F-. However, a progressive degradation of titanium was observed at a F- concentration of 12,300 ppm. Additionally, the corrosion and wear resistance of the titanium oxide film formed at a F- concentration of 12,300 ppm differ from the ones obtained up to 227 ppm F- reflected by a decrease of the coefficient of friction although the material loss increased. The synergism between wear and corrosion processes on titanium needs thus to be further investigated to reach a reliable prediction of the long-term behavior of titanium-based prostheses and implants in the oral cavity.

Titanium surface topography after brushing with fluoride and fluoride-free toothpaste simulating 10 years of use

Fais, Laiza M. G.; Fernandes-Filho, Romeu B.; Silva, Marcelo de Assumpção Pereira da; Vaz, Luis G.; Adabo, Gelson L.
Fonte: ELSEVIER SCI LTD; OXFORD Publicador: ELSEVIER SCI LTD; OXFORD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.95%
Objectives: To conduct a controlled study contrasting titanium surface topography after procedures that simulated 10 years of brushing using toothpastes with or without fluoride. Methods: Commercially pure titanium (cp Ti) and Ti-6Al-4V disks (6 mm circle divide x 4 mm) were mirror-polished and treated according to 6 groups (n = 6) as a function of immersion (I) or brushing (B) using deionised water (W), fluoride-free toothpaste (T) and fluoride toothpaste (FT). Surface topography was evaluated at baseline (pretreatment) and post-treatment, using atomic force microscope in order to obtain three-dimensional images and mean roughness. Specimens submitted to immersion were submerged in the vehicles without brushing. For brushed specimens, procedures were conducted using a linear brushing machine with a soft-bristled toothbrush. Immersion and brushing were performed for 244 h. IFT and BFT samples were analysed under scanning electron microscope with Energy-Dispersive X-ray Spectroscopy (EDS). Pre and post-treatment values were compared using the paired Student T-test (alpha = .05). Intergroup comparisons were conducted using one-way ANOVA with Tukey post-test (alpha = .05). Results: cp Ti mean roughness (in nanometers) comparing pre and post-treatment were: IW...

Avaliação da fusibilidade, desajuste marginal e união metalocerâmica do titânio comercialmente puro em função do tipo de revestimento e da temperatura final do molde; Evaluation of the castability, marginal misfit, and metal-ceramic bond strength of the commercially pure titanium in terms of investment type and mold final temperature

Macedo, Mônica Barbosa Leal
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 31/01/2008 PT
Relevância na Pesquisa
37.01%
O propósito deste trabalho foi avaliar a fusibilidade, o desajuste marginal e a resistência de união metalocerâmica (RUMC) do titânio comercialmente puro (CP) em função do tipo de revestimento, Rematitan Plus (P) ou Rematitan Ultra (U), e da temperatura final do molde: 400°C (T1), 550°C (T2) ou 700°C (T3). A partir de uma matriz metálica com linha de término cervical em bisel de 30°, foram obtidos sessenta padrões de resina/cera em forma de coping para os ensaios de fusibilidade e desajuste marginal. Para o ensaio de RUMC, foram obtidos sessenta padrões de resina/cera em forma de cilindro, com 8 mm de comprimento e 5 mm de diâmetro, utilizando uma matriz de teflon. Os padrões foram incluídos em dois revestimentos para titânio (P e U), compreendendo um coping e um cilindro para cada um dos anéis, que foram submetidos a ciclos térmicos, com variação da temperatura final (T1, T2 e T3) e fundidos em titânio CP. Após resfriamento, as fundições foram desincluídas e jateadas com óxido de alumínio (100 µm). Depois de recortados dos canais de alimentação, os copings foram submetidos aos ensaios de fusibilidade e desajuste marginal, enquanto os cilindros foram preparados para aplicação da cerâmica: suas superfícies foram usinadas...

Análise histomorfométrica dos implantes de titânio grau 4 e grau 5: estudo experimental em coelhos; Histomorphometric evaluation of titanium implants grade 4 and grade 5: experimental study in rabbits

Miranda, Aline Baia
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/05/2013 PT
Relevância na Pesquisa
37.03%
Os implantes dentários de titânio comercialmente puro (Ticp) grau 4 e os de titânio-alumínio-vanádio (Ti6Al4V) grau 5, possuem boas propriedades mecânicas. No entanto, algumas situações clínicas com restrição de espessura óssea impedem a utilização dos implantes com 3.75mm de diâmetro tradicionalmente fabricados em titânio 4 e que apresentam resistência mecânica testada em profusão. Como a liga de grau 5 possui superior resistência à tração e à fadiga, este estudo objetiva analisar a resposta óssea do titânio grau 4 e grau 5 em implantes curtos e estreitos através da análise do contato osso-implante (BIC) e da área de neoformação óssea. Para este fim, o presente estudo utilizou 15 coelhos da raça New Zealand, que receberam um total de trinta implantes divididos em suas tíbias direita e esquerda. Os implantes de grau 4 e de grau 5, com dimensões de 3.5x8mm e 2.9x7mm, respectivamente, foram fornecidos pela empresa NEODENT® (Curitiba-Brasil). Neste estudo, dois grupos foram formados, um com implantes de titânio grau 4 e outro com implantes de titânio grau 5, ambos contendo quinze implantes curtos e estreitos. Cortes histológicos foram realizados após duas semanas de osseointegração. Mensurações no analisador de imagens ImageJ foram feitas para verificar o BIC e a área de osso neoformado. Para a análise dos dados estatísticos...

What is the role of lipopolysaccharide on the tribocorrosive behavior of titanium?

Mathew, Mathew T.; Barao, Valentim Adelino Ricardo; Yuan, Judy Chia-Chun; Assuncao, Wirley G.; Sukotjo, Cortino; Wimmer, Markus A.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 71-85
ENG
Relevância na Pesquisa
37.07%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 07/58926-5; In an oral environment, titanium dental implants are exposed to a complex degradation process which is predominantly influenced by the intermittent mechanical events (mastication), continuous exposure to varying chemical solutions (saliva and food) and formation of microbiological (biofilm). Several studies have investigated the chemical corrosion and mechanical resistance of titanium; however, very few attempted to report on the effects of combined chemical, mechanical and microbiological interactions, which simulates the oral environment. A new multi-disciplinary research area, tribocorrosion (a combined study of wear and corrosion), was used to address such issues. The tribocorrosive nature of titanium in artificial saliva (pH 6.5) with lipopolysaccharide (LPS) was investigated. Rventy-four titanium discs (12 mm diameter, 7 mm thickness), were divided into 8 groups (n = 3) as a function of material (commercially pure titanium (cpTi) and titanium-aluminum-vanadium (TiAlV) alloy) and LPS concentrations (0, 0.15, 15 and 150 mu g/ml). Sliding duration (2000 cycles), frequency (1.2 Hz) and load (20 N) parameters mimicked the daily mastication process. Electrochemical impedance spectroscopy was conducted before and after tribocorrosion to comprehend the changes in corrosion kinetics. Worn surfaces were examined using white-light-interferometry and scanning electron microscopy. Total weight loss and roughness values were calculated. LPS affected the tribocorrosive behavior of both titanium types. LPS statistically accelerated the ion exchange between titanium and saliva...

CATHODIC BEHAVIOUR of ANODIZED TITANIUM IN SIMULATED PHYSIOLOGICAL CONDITIONS

Pelaez Abellan, E.; Rocha-Sousa, L.; Guastaldi, A. C.
Fonte: Plapiqui(uns-conicet) Publicador: Plapiqui(uns-conicet)
Tipo: Artigo de Revista Científica Formato: 199-203
ENG
Relevância na Pesquisa
36.98%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); In the present work, anodic oxide films on titanium specimens were formed in physiological solution under potentiostatic condition. The immediate- to short-term changes in the oxide film were studied by open-circuit potential measurements and cyclic voltammetry. The results show that the intensity of the cathodic current peak related to oxygen reduction at around -0.7 Vsce, decreased and disappeared after 30 minutes of finishing the anodic oxidation. For titanium without anodization (non-coated titanium), the cyclic voltammograms show an anodic current in the range that begins at -0.9 Vsce and continues to more positive potentials (vs SCE), related to the hydrogen oxidation reaction. For anodically polarized titanium (coated titanium), in the anodic direction of the cyclic voltammograms an anodic current in the range that begins at -0.9 Vsce and continues to more positive potentials (vs SCE) was observed. In this case, the oxidation process is related to previous cathodic processes: the hydrogen formation and the cathodic transformation of titanium oxides before the oxygen reduction potential region.

Osteogenesis-inducing calcium phosphate nanoparticle precursors applied to titanium surfaces

He, Wenxiao; Andersson, Martin; De Souza, Pedro Paulo Chaves; De Souza Costa, Carlos Alberto; Muñoz, Eduardo Mariscal; Schwartz-Filho, Humberto Osvaldo; Hayashi, Mariko; Hemdal, Amanda; Fredel, Axel; Wennerberg, Ann; Jimbo, Ryo
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.95%
This study investigated the effects of the morphology and physicochemical properties of calcium phosphate (CaP) nanoparticles on osteogenesis. Two types of CaP nanoparticles were compared, namely amorphous calcium phosphate (ACP) nano-spheres (diameter: 9-13 nm) and poorly crystalline apatite (PCA) nano-needles (30-50 nm x 2-4 nm) that closely resemble bone apatite. CaP particles were spin-coated onto titanium discs and implants; they were evaluated in cultured mouse calvarial osteoblasts, as well as after implantation in rabbit femurs. A significant dependence of CaP coatings was observed in osteoblast-related gene expression (Runx2, Col1a1 and Spp1). Specifically, the PCA group presented an up-regulation of the osteospecific genes, while the ACP group suppressed the Runx2 and Col1a1 expression when compared to blank titanium substrates. Both the ACP and PCA groups presented a more than three-fold increase of calcium deposition, as suggested by Alizarin red staining. The removal torque results implied a slight tendency in favour of the PCA group. Different forms of CaP nanostructures presented different biologic differences; the obtained information can be used to optimize surface coatings on biomaterials. © 2013 IOP Publishing Ltd.

Mechanical and chemical analyses across dental porcelain fused to CP titanium or Ti6Al4V

Souza, Julio C. M.; Henriques, Bruno; Ariza, Edith; Martinelli, Antonio E.; Nascimento, Rubens M.; Silva, Filipe S.; Rocha, Luis A.; Celis, Jean-Pierre
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 76-83
ENG
Relevância na Pesquisa
36.95%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); The aim of this study was to evaluate the evolution of mechanical properties and chemical variation across veneering dental porcelain fused to different titanium-based substrates. Test samples were synthesized by fusing dental feldspar-based porcelain onto commercially pure titanium grade II or Ti6Al4V alloy. Samples were cross-sectioned at angles of 10 and 90 degrees to the interface plane. Afterwards, nanoindentation tests and Scanning Electron Microscopy (SEM) imaging coupled to an Energy Dispersive Spectroscopy (EDS) system were carried out across interfaces extending from the metal towards the porcelain area. Elemental diffusion profiles across the porcelain-to-metal interfaces were also obtained by EDS analysis. The mismatch in mechanical properties found in porcelain-to-Ti6Al4V interfaces was lower than that of porcelain-to-CP titanium. Cracking was noticed at low-thickness veneering dental porcelain regions after the nanoindentation tests of samples cross-sectioned at low angles to the interface plane. A wide reaction zone between titanium and porcelain as well as higher incidence of defects was noticed at the porcelain-to-CP titanium interfaces. This study confirmed Ti6Al4V as an improved alternative to CF-titanium as it showed to establish a better interface with the veneering dental porcelain considering the slight chemical interaction and the lower mechanical properties mismatch. The elastic modulus of porcelain-to-Ti6Al4V samples showed to be less sensitive to porcelain thickness variations. (C) 2013 Elsevier B.V. All rights reserved.

Envolvimento dos TLR2 e TLR4 no reconhecimento das partículas de titânio e zircônia por macrofagos murinos; Involvement of TLR2 and TLR4 in recognition of particles of titanium and zirconia by murine macrophages

Gustavo Alberto Obando Pereda
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 30/01/2012 PT
Relevância na Pesquisa
37.03%
A reação biológica as partículas de desgaste é crítica para indução da perda asséptica do implante mediante a osteólise. Deste modo, foi objetivo deste trabalho avaliar o envolvimento dos receptores Toll-like receptors 2 e 4 no reconhecimento das partículas de titânio e zircônia. Mensurados em cultura de macrófagos murinos desafiados com as partículas de zircônia ou de titânio comparando a expressão de TLRs, seus adaptadores intracelulares e citocinas pró-inflamatórias. Em in vivo foram estudados a indução da osteolise utilizando o modelo de calvária e a geração da resposta inflamatória através da indução do edema e hiperalgesia. As partículas são prontamente fagocitadas pelos macrófagos em cultura, e resultam no aumento da expressão de RNAm para TLRs 2, 3, 4 e 9, os seus adaptadores MyD88 e NF-kB e das citocinas TNF-?, IL-1? e IL-6. Contudo, o padrão de expressão de RNAm para TLRs entre as partículas é distinto, enquanto a zircônia induz um aumento significativamente na expressão de TLR2, o titânio modula a expressão significativamente maior de TLR3, TL4 e TLR9, respectivamente. Todavia, a expressão do RNAm para a molécula adaptadora MyD88 envolvida na sinalização intracelular de TLR é estimulada em ambas as partículas e com uma cinética de expressão semelhante. O fator de transcrição NF-kB necessário para efetuar a expressão gênica das citocinas envolvidas na resposta inflamatória apresenta uma cinética de expressão distinta entre as partículas...

Synthesis and physicochemical characterization of titanium oxide and sulfated titanium oxide obtained by thermal hydrolysis of titanium tetrachloride

Esteban Benito,H.; Del Ángel Sánchez,T.; García Alamilla,R.; Hernández Enríquez,J. M.; Sandoval Robles,G.; Paraguay Delgado,F.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2014 EN
Relevância na Pesquisa
37.03%
This work reports the synthesis of titanium oxide (TiO2) and sulfated titanium oxide (TiO2-SO4(2-)) obtained by thermal hydrolysis of titanium tetrachloride. Titanium hydroxide synthesized by this method was impregnated with a 1 N H2SO4 solution, to give amounts of sulfate ions (SO4(2-)) of 3 and 7 wt%. The synthesized samples were dried at 120 °C during 24 h and then calcined for 3 h at 400 °C. Thermal analyses, X-ray diffraction, nitrogen physisorption, infrared spectroscopy, potentiometric titration with n-butylamine, U.V.-visible diffuse reflectance spectroscopy and scanning electron microscopy were used to characterize the materials. The results of physicochemical characterization revealed that a mixture of crystalline structures, anatase, brookite and rutile developed in the titanium oxide, stabilizing the anatase structure in the sulfated titanium oxides, and coexisting with a small amount of brookite structure. The synthesized mesoporous materials developed specific surface areas between 62 and 70 m² g-1, without detecting an important influence of sulfation on this parameter. The presence of sulfate ions improved the acidity of titanium oxide and modified the characteristics of light absorption in the 425-600 nm region...

Serum titanium, niobium, and aluminum levels after instrumented spinal arthrodesis in children

Cundy, T.; Antoniou, G.; Sutherland, L.; Freeman, B.; Cundy, P.
Fonte: Lippincott Williams & Wilkins Publicador: Lippincott Williams & Wilkins
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
Relevância na Pesquisa
37.03%
STUDY DESIGN. A prospective cohort study. OBJECTIVE. To determine serum titanium, niobium, and aluminum levels in pediatric patients within the first postoperative year after instrumented spinal arthrodesis. SUMMARY OF BACKGROUND DATA. Instrumented spinal arthrodesis is a common procedure to correct scoliosis and kyphosis. Titanium-based instrumentation is increasingly favored due to enhanced biomechanical properties, but concerns have arisen regarding metal debris release and the potential for local and systemic complications. METHODS. The pattern of systemic metal release over time was evaluated by measuring serum titanium, niobium, and aluminum levels preoperatively and 1 week, 1 month, 6 months, and 12 months after instrumented spinal arthrodesis using a titanium alloy. Serum metal levels were measured using high-resolution inductively coupled plasma mass spectrometry. RESULTS. Thirty-two patients were included in the study group. Mean age at surgery was 14.7 years. Preoperative and postoperative concentrations of serum titanium and niobium were significantly different (P = 0.0001). Median postoperative serum concentrations of titanium and niobium were elevated 2.4- and 5.9-fold above the normal range respectively with 95% and 99% of samples elevated postoperatively. A significant and rapid rise in serum titanium and niobium levels was observed within the first postoperative week...

Comparative study of bond characteristics between titanium/titanium alloy and ceramic; Comparative study of bond characteristics between titanium/titanium alloy and ceramic; Die vergleichende Untersuchung von Verbundeigenschaft zwischen Reintitan/Titanlegierung und Keramik

Lee, Ho-Rim
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
Relevância na Pesquisa
37.08%
Heutzutage ist der Gebrauch Titan-keramischer Restauration vermehrt, aber es gibt einige Probleme, die gelöst werden müssen. Um die Festigkeit von unlegiertem Titan zu verbessern, wurde die TiAl6Nb7 Legierung entwickelt, die einen höheren Wärmeausdehnungskoeffizient im Vergleich zu Reintitan hat. Aufgrund der verschiedenen Wärmeausdehnungskoeffizienten und elastischen Eigenschaften von Titan/Titan Legierung und verblendeter Keramik, beeinflusst die entstehende Spannung die metallkeramische Kompatibilität. Der Tübinger Gabel Test wurde entwickelt, um die thermische Kompatibilität zwischen Metall und verblendeter Keramik experimentell bewerten zu können. Das Ziel dieser Untersuchung sollte sein, die effektive thermische Kontraktionsdifferenz zu berechnen und die Verbundfestigkeit am System Reintitan/TiAl6Nb7 Legierung mit Keramik zu messen. Gabelförmige Prüfkörper mit zwei parallelen Ästen wurden von Reintitan Grade 2 und TiAl6Nb7 Legierung mit dem Einkammer-Vakuum-Druckgussgerät mit Lichtbogen-Schmelzeinrichtung gegossen. Nach der Oberflächebearbeitung mit SiC 1200 und Reinigen in Äthylalkohol, wurde Titankeramik auf der entgegengesetzten Seite jeden Astes gemäß Herstellerangaben verblendet. Nach dem Abkühlen wurde der Abstand der Durchbiegung der zwei Äste mit dem Mikroskop an der Front der Äste gemessen. Auf der Basis dieser Daten wurde die effektive thermische Kontraktionsdifferenz zwischen rein Titan/TiAl6Nb7 Legierung und Keramik berechnet. Der Dreipunktbiegeversuch nach Schwickerath wurde gemäß ISO 9693 durchgeführt...

Nano Hydroxyapatite/Collagen, Nano Hydroxyapatite and Anodic Oxides on Titanium - Preparation, Characterization and Biological Responses -; Nano Hydroxyapatite/Kollagen, Nano Hydroxyapatite und Anodische Oxide auf Titanium - Präparationen, Charakterisierungen and Biologische Antworten -

Zhu, Xiaolong
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
EN
Relevância na Pesquisa
36.98%
Aim The purpose of the present study is to develop, characterize and biologically evaluate a new surface for titanium implants to optimize osseointegration at the bone-implant interface. Materials and Metholds After pretreatment procedure, rectangular cp titanium specimens were anodized in a galvanostatic mode with a current density of 70 A/m2 till different voltages using either 0.2 M H3PO4 solution or a mixture of 0.03 M calcium glycerophosphate (Ca-GP) and 0.15 M calcium acetate (CA) as electrolyte. Surface characterization were performed including morphology, roughness, wettability, chemical compositions and states of elements. UV-irradiation was performed for 1 hours under two 254 nm UV-light bulbs. Nano HA was synthesized and its structure was analyzed by XRD and TEM. Collagen type I (calf skin) was homogeneously mixed with nano HA sol, and then the mixture was coated on the Ti surfaces. In vitro studies including cytotoxicity, cell attachment and spreading, cell proliferation and alkaline phosphatase activity were investigated into anodic oxides, nano HA and nano HA/collagen surfaces by cell culture and evaluation with the SaOS-2 human osteoblast-like cell line, derived from a human osteosarcoma. Results With an increase of anodizing voltages...

Osteoblasts response to anodized commercially pure titanium in vitro; Reaktion von Osteoblasten auf anodische Oxidation von technisch reinem Titan in vitro

Chen, Jun
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
EN
Relevância na Pesquisa
36.98%
In this study, the effect of anodized titanium surfaces on osteoblast-like cells behavior was investigated. Grade 2 commercially pure titanium specimens with 20x10x1 mm in size was anodized in two electrolytes with different compositions: 1) 0.2 M H3PO4 and 2) 0.03 M Ca-GP and 0.15 M CA. In the electrolyte 1, 200v, 300v, and 350v anodized voltages were used; 140v, 200v, 260v, and 300v were adopted in the electrolyte 2. Because of the different anodizing conditions, various oxide layers with different surface properties and chemical compositions were formed. To evaluate biocompatibility of these anodized titanium surfaces, cell culture of osteoblast-like cell line (Saos-2) was carried out. In current study, cytotoxicity test, cell attachment and spreading, cell morphology, cell proliferation and differentiation were estimated. The result of cytotoxicity test showed that anodic oxidation on titanium was not toxic. Cell attachment was enhanced on anodized titanium surfaces after 1 or 2 h cell culture. Marked morphologic difference of osteoblasts on anodized titanium surfaces was observed when compared with that on cp Ti. After 4 days cell culture, higher cell proliferation was shown on most of the anodized surfaces. In summary, the anodic oxidation technique investigated in present study had an effect on early osteoblast behaviour and may improve biocompatibility of titanium.; In dieser Studie wird der Effekt von anodisch oxidierten Titan- Oberflächen auf Osteoblasten untersucht. Proben aus technisch reinem Titan ( Grad 2) mit der Größe 20x10x1 mm wurden in zwei Elektrolyten mit verschiedenen Kompositionen anodisiert: 1) 0...

Processing of Elemental Titanium by Powder Metallurgy Techniques

Bolzoni, Leandro; Ruiz Navas, Elisa María; Gordo Odériz, Elena
Fonte: Trans. Tech. Publications Publicador: Trans. Tech. Publications
Tipo: info:eu-repo/semantics/acceptedVersion; info:eu-repo/semantics/conferenceObject; info:eu-repo/semantics/article Formato: application/pdf
Publicado em 24/07/2013 ENG
Relevância na Pesquisa
37.01%
Titanium is characterised by an outstanding combination of properties like high strength, low density, good corrosion resistance and biocompatibility. Nonetheless, widespread employment of titanium at the industrial level, especially in the automotive industry, has not been achieved yet because of its high extraction and production costs. Consequently, titanium finds applications mainly in high demanding sectors, such as the aerospace industry or to produce biomedical devices, where the final high cost is not the principal issue. The processing of titanium and its alloys by means of powder metallurgy (PM) techniques is claimed to be a suitable way to reduce the fabrication cost of titanium products as well as offering the possibility to design new alloys which are difficult to obtain using the conventional metallurgical route, for example due to segregation of heavy alloying elements. This work deals with the processing of hydride-dehydride elemental titanium powder by means of different PM methods and aims at investigating the processing of near net-shape, chemically-homogeneous and fine-grained titanium-based components. In particular, properties achievable (i.e. relative density, microstructure and mechanical properties) and problems related to the processing of elemental titanium...

Study of the properties of low-cost powder metallurgy titanium alloys by 430 stainless steel addition

Bolzoni, Leandro; Herraiz, E.; Ruiz Navas, Elisa María; Gordo Odériz, Elena; Gordo Odériz, Elena
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: info:eu-repo/semantics/acceptedVersion; info:eu-repo/semantics/article
Publicado em /08/2014 ENG
Relevância na Pesquisa
37.01%
Titanium is a lightweight metal with an outstanding combination of properties which make it the material of choice for many different applications. Nonetheless, its employment at industrial level is not widespread due to higher production costs with respect to competitor metals like steel and aluminium. In this work the production of low-cost titanium alloys is attempted by combining the utilisation of a powder metallurgy process and cheap alloying elements (i.e. commercial 430 stainless steel powder optimised for the powder metallurgy industry). Low-cost titanium alloys are fabricated by blending elemental titanium with stainless steel. The behaviour of the powders as well as that of the sintered materials are analysed and compared to that of a master alloy addition Ti6Al4V alloy. The produced low-cost titanium alloys show comparable properties to both wrought and powder metallurgy titanium alloys and, therefore, they are proposed as an alternative to obtain structural component made out of titanium alloys.; The authors want to acknowledge the financial support from the Spanish Ministry of Science through the R&D Projects MAT2012-38650-C02-01, and from Regional Government of Madrid through the ESTRUMAT (S2009/MAT-1585) project

Cathodic behaviour of anodized titanium in simulated physiological

Peláez Abellán,E.; Rocha-Souza,L.; Guastaldi,A. C.
Fonte: Latin American applied research Publicador: Latin American applied research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2011 EN
Relevância na Pesquisa
36.98%
In the present work, anodic oxide films on titanium specimens were formed in physiological solution under potentiostatic condition. The immediate- to short-term changes in the oxide film were studied by open-circuit potential measurements and cyclic voltammetry. The results show that the intensity of the cathodic current peak related to oxygen reduction at around -0.7 Vsce, decreased and disappeared after 30 minutes of finishing the anodic oxidation. For titanium without anodization (non-coated titanium), the cyclic voltammograms show an anodic current in the range that begins at -0.9 Vsce and continues to more positive potentials (vs SCE), related to the hydrogen oxidation reaction. For anodically polarized titanium (coated titanium),in the anodic direction of the cyclic voltammograms an anodic current in the range that begins at -0.9 Vsce and continues to more positive potentials vs SCE) was observed. In this case, the oxidation process is related to previous cathodic processes: the hydrogen formation and the cathodic transformation of titanium oxides before the oxygen reduction potential region.

Titanium production via metallothermic reduction of TiCl4in molten salt: Problems and products

van Vuuren,D.S.; Oosthuizen,S.J.; Heydenrych,M.D.
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 EN
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37.03%
Industrial production of titanium occurs via the batch-wise reduction of titanium tetrachloride (TiCl4) with a reducing metal, being magnesium in the Kroll process, or sodium in the Hunter process. In the search for low cost titanium, the CSIR is developing a continuous process to produce titanium powder directly via metallothermic reduction of TiCl4 in molten salt, dubbed the CSIR-Ti process. The move to a continuous process has been attempted by a number of organizations, but was until now always met with failure, due in no small part to challenges inherent in the process chemistry. The reaction between TiCl4 and the reducing metal can occur directly, when TiCl4 or any titanium sub-chlorides present, comes into contact with suspended or dissolved reducing metal. The reaction can also occur indirectly, without any physical contact between the reacting species, via an electronically mediated mechanism. The reaction mechanism via electronic mediation can cause TiCl4 to react at the outlet of the feed port, rapidly causing blockages of the TiCl4 feed line. The electrical conductivity of the metal reactor can also cause the electronically mediated reaction to favour the formation of titanium sponge on the reactor walls and internals, rather than titanium powder. Various methods were investigated to overcome the problem of blockages in the TiCl4 feed line...

The use of titanium hydride in blending and mechanical alloying of Ti-Al alloys

Mwamba,I.A.; Chown,L.H.
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 EN
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Titanium sponge, which is almost pure titanium, is extremely ductile and not easily processed into titanium powder. One method of producing powder is the hydride-dehydride (HDH) process, where titanium sponge is hydrided to form brittle titanium hydride (TiH2). Titanium hydride is easily milled to produce powder and is then dehydrided to form Ti powder. In this work, titanium hydride powder obtained from titanium sponge was used as a starting material for blending and mechanical alloying with elemental powders. Firstly, titanium hydride powder was blended with aluminium elemental powder to produce a homogenized powder, which was then compacted and sintered to produce powder metallurgy compacts. Secondly, titanium hydride powder was mechanically alloyed with aluminium elemental powder and then compacted. The mechanically alloyed powder was characterized in terms of particle size distribution, morphology and microstructure. In both blending and mechanical alloying, the green compacts were characterized by assessing the green density, while the sintered compacts were characterized by their sintered density, microstructure, and hardness. The two processes have resulted in the formation of TiAl3 intermetallic compound. It was established that by simple mixing and homogenizing...

Titanium: the innovators' metal - Historical case studies tracing titanium process and product innovation

Oosthuizen,S.J
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2011 EN
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37.04%
This paper examines innovation in relation to the availability of a new material: the metal titanium. The paper aims to highlight the need for the inclusion of entrepreneurial innovation as a necessary focus area in the development of a titanium metal value chain. Both the Department of Science and Technology (DST) and the Department of Mineral Resources (DMR) have identified the creation of titanium metals production capabilities as a key growth area for South Africa. Using historical literature as a source of data, the activities of selected innovators who used titanium metal as a central component in their success, were investigated. The origin of the process innovation behind the titanium metals industry, and two titanium product innovations: namely, medical implants and sporting goods, were detailed as case studies. It was found that individual innovators were responsible for the creation, and rapid growth, of the titanium industry and titanium product applications. There is a need to link the current research and development into titanium metals production with individuals and organizations capable of commercializing innovative processes and products.