Processing of dense nanostructured HAP ceramics by sintering and hot pressing

Veljović, Djordje; Jokić, Bojan; Petrović, Rada; Palcevskis, E.; Dindune, A.; Mihăilescu, I. N.; Janaćković, Dj.

doi:10.1016/j.ceramint.2008.07.007

Cited by 93 publications

(45 citation statements)

References 29 publications

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“…Nano-sized HAP powders doped with Sr and Mn ions were synthesized by modified precipitation methods, based on the chemical interaction between calcium hydroxide and phosphoric acid, as most suitable method for the synthesis of nano-sized HAP powders [24,33,34]. Strontium and manganese ions were added into the starting solutions in order to substitute calcium ions in the HAP structure, in different forms and in different percents (according to the optimal literature data) [7][8][9]21].…”

Section: Powder Synthesismentioning

confidence: 99%

“…Generally, the brittle nature and low fracture toughness of biphasic HAP/TCP bioceramics often limit the use of these materials in some load-bearing clinical applications [1,2,23,24]. High temperatures of conventional sintering often result in extreme grain coarsening, which further results in breakable biceramic materials.…”

Section: Introductionmentioning

confidence: 98%

“…During the first step of two-step sintering, the pressed samples were always heated to the higher temperature in order to achieve sufficient activation energy for attaining of critical density, and temperature of the second step must be lower but sufficient to result with high density of materials without grain growth [28]. Noticeable improvements in the fracture toughness and hardness of HAP-based bioceramic materials were achieved through control of the grain size [24,29,30]. Decreasing in the grain size of HAP could additionally result in biocompatibility improvement of potential implant materials and improved cell attachment and their proliferation [31,32].…”

Section: Introductionmentioning

confidence: 99%

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The influence of Sr and Mn incorporated ions on the properties of microwave single- and two-step sintered biphasic HAP/TCP bioceramics

et al. 2014

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The aims of this study were to investigate the effects of Sr-and Mn-doped ions on the sintering behaviors, microstructure and mechanical properties of the bioceramics processed by single-and two-step microwave sintering (MWSSS and MWTSS). Nano-sized calcium hydroxyapatite powders doped with Sr and Mn ions, obtained by modified precipitation synthesis, were isostatically pressed at 400 MPa and processed by MWSSS and MWTSS at different temperatures. In all cases during the sintering, the doped HAP powders turned into biphasic mixtures of HAP and TCP, but the amount of TCP was certainly lower in the case of MWTSS. It was shown that the doped ions significantly affected: density, microstructure, grain size, porosity, hardness, and fracture toughness of the processed bioceramics. Two-step microwave sintering was successfully applied for the processing of HAP/ TCP bioceramics doped with strontium and manganese ions. Both two-step microwave sintered doped bioceramics had similar and high hardness values, but the strontiumsubstituted bioceramic material certainly had higher fracture toughness (1.54 MPam 1/2 ), with an average grain size of 195 nm. Based on the results presented in this paper, it was concluded that the two-step microwave sintered strontium-doped bioceramics could be suitable materials in the bone regenerative field.

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Section: Powder Synthesismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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The influence of Sr and Mn incorporated ions on the properties of microwave single- and two-step sintered biphasic HAP/TCP bioceramics

et al. 2014

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“…For the fourth variant, concentrated NH 4 (OH) 2 was added to vigorously stirred water, pH = 10, and then NH 4 PO 3 and Ca(NO 3 ) 2 were added drop-wise while stirring for 10 min at room temperature and, then, the HA precipitate was placed in a Teflon liner that was sealed tightly in an autoclave and processed hydrothermally, at 200 o C for 20 h [39,40]. The fifth variant is a modification of the fourth one, with the modification involving spray-drying the HA precipitate at 120 ± 5 o C [41]. The fourth method is a hydrothermal method, in which microcrystalline HA is precipitated for 10 min at room temperature, after which some of supernatant is removed by centrifuging once to reduce the suspension by 75%, and then the concentrated HA-precipitated aqueous solution is placed on a tightlysealed Teflon ® liner that is in an autoclave and, finally, processed hydrothermally at 200 o C for 20 h [39].…”

Section: Nanophase Hydroxyapatite Powdermentioning

confidence: 99%

Nanostructured Hydroxyapatite Coating on Bioalloy Substrates: Current Status and Future Directions

Lewis¹

2017

JAN

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Abstract. Several shortcomings of the alloys that are used to fabricate a number of currentgeneration biomedical implants, such as Ti-6Al-4V alloy for the femoral stem of a total hip replacement and AZ3 Mg alloy for the scaffold of a fully bioabsorbable coronary artery stent, are well-known. Examples of these shortcomings are limited bioactivity/osseointegration (in the case of Ti-based alloys) and high corrosion rate (in the case of Mg-based alloys). It is now recognized that a nanostructured hydroxyapatite (nanoHA) coating on the substrate of a bioalloy can increase bioactivity and reduce corrosion of the substrate. A large number of nanoHA deposition methods and a variety of characterization techniques/methods have been used to obtain an assortment of properties of the coating, the coated specimens, and the coating-substrate interface. Examples of these deposition methods are electrophoretic deposition and radiofrequency magnetron sputtering and some of the most frequently used characterization techniques/methods are x-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, immersion tests in a biosimulating solution at 37 o C, and culturing in cells extracted from humans. Among the properties obtained are the morphology, thickness, size of the nanoHA; degree of crystallinity of the coating; and the adhesive strength and corrosion rate in an aqueous biosimulating solution at 37 o C. The present work is a comprehensive review of the very large body of literature in this field, with the focal topics being essential steps in a deposition method, discussion of the influence of deposition method variables on myriad coating properties (for a given deposition method), and identification of the shortcomings of the literature, and, hence, outlines of ten suggested directions for future research.

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“…To types of bioglasses were used for deposition: BG57 whit the composition 56.5% SiO 2 , 11% Na 2 O, 3% K 2 O, 15% CaO, 8.5% MgO, 6% P 2 O 5 and BG61 having the composition 61.1% SiO 2 , 10.3% Na 2 O, 2.8% K 2 O, 12.6% CaO, 7.2% MgO, 6% P 2 O 5 (Veljovic et al, 2009). Biomedical grade 4 Ti was used as substrate because it exhibits a good biocompatibility and is resistant to corrosion, properties which make it a good candidate for fabrication in orthopedic implants.…”

Section: Maple Experimentsmentioning

confidence: 99%

Polymer-Bioglass Composite Coatings: A Promising Alternative For Advanced Biomedical Implants

Floroian¹,

Popescu²,

Serban³

et al. 2011

Metal, Ceramic and Polymeric Composites for Various Uses

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Processing of dense nanostructured HAP ceramics by sintering and hot pressing

Cited by 93 publications

References 29 publications

The influence of Sr and Mn incorporated ions on the properties of microwave single- and two-step sintered biphasic HAP/TCP bioceramics

The influence of Sr and Mn incorporated ions on the properties of microwave single- and two-step sintered biphasic HAP/TCP bioceramics

Nanostructured Hydroxyapatite Coating on Bioalloy Substrates: Current Status and Future Directions

Polymer-Bioglass Composite Coatings: A Promising Alternative For Advanced Biomedical Implants

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