scholarly journals Advances in Sintering Techniques for Calcium Phosphates Ceramics

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6133
Author(s):  
Abhishek Indurkar ◽  
Rajan Choudhary ◽  
Kristaps Rubenis ◽  
Janis Locs
Keyword(s):  
Bone Regeneration ◽  
Thermal Instability ◽  
Treatment Process ◽  
Sintering Temperature ◽  
Calcium Phosphates ◽  
External Pressure ◽  
Secondary Phases ◽  
Conventional Sintering ◽  
Long Time ◽  
Inorganic Mineral

Calcium phosphate (CaP) biomaterials are extensively used to reconstruct bone defects. They resemble a chemical similarity to the inorganic mineral present in bones. Thus, they are termed as the key players in bone regeneration. Sintering is a heat treatment process applied to CaP powder compact or fabricated porous material to impart strength and integrity. Conventional sintering is the simplest sintering technique, but the processing of CaPs at a high temperature for a long time usually leads to the formation of secondary phases due to their thermal instability. Furthermore, it results in excessive grain growth that obstructs the densification process, limiting the application of CaP’s ceramics in bone regeneration. This review focuses on advanced sintering techniques used for the densification of CaPs. These techniques utilize the synergy of temperature with one or more parameters such as external pressure, electromagnetic radiation, electric current, or the incorporation of transient liquid that boosts the mass transfer while lowering the sintering temperature and time.

Influence of Sintering Temperature on Structure and Electrical Properties of Modified-BNKT Lead-Free Piezoelectric Ceramics

2018 ◽  
Vol 777 ◽  
pp. 55-59 ◽  
Author(s):  
Pharatree Jaita ◽  
Supalak Manotham ◽  
Narumon Lertcumfu
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Mixed Oxide ◽  
Sintering Temperature ◽  
Ferroelectric Properties ◽  
Maximum Density ◽  
Lead Free ◽  
Secondary Phases ◽  
Xrd Pattern ◽  
Conventional Sintering

In this research, the effects of sintering temperature on phase structure, densification, microstructure, and electrical properties of modified-BNKT ceramics were investigated. Conventional sintering of lead-free 0.97Bi0.5(Na0.80K0.20)0.5TiO3-0.03(Ba0.70Sr0.30)O3or 0.97BNKT-0.03BSrT ceramic was investigated to clarify the optimal sintering temperature for densification and electrical properties. All ceramics were prepared by a conventional mixed oxide and sintered at various temperatures from 1100 to 1150°C. XRD pattern indicated all ceramics exhibited a single perovskite without any secondary phases. The maximum density of 5.80 g/cm3with relative density of 99.32% were observed for the ceramic sintered at 1125°C. Grain size tended to increase with increasing the sintering temperature. The good dielectric (Td= 121 °C, Tm= 320 °C and e¢max= 4982) and ferroelectric properties (Pr= 16.66 µC/cm2, Ec= 17.85 kV/cm and Rsq= 0.74) were obtained for the ceramic sintered at optimum sintering temperature of 1125°C.

Effect of Silver Ions on the Structural and Antibacterial Properties of Bone Replacement Material

2013 ◽  
Vol 795 ◽  
pp. 692-696 ◽  
Author(s):  
Nida Iqbal ◽  
Mohammed Rafiq Abdul Kadir ◽  
Nasrul Humaimi Bin Mahmood ◽  
Micheal Moses ◽  
Mashitah Binti Mad Salim ◽  
...  
Keyword(s):  
Calcium Phosphates ◽  
Bacterial Species ◽  
Calcium Nitrate ◽  
Antibacterial Properties ◽  
Silver Ions ◽  
Antibacterial Activities ◽  
Silver Addition ◽  
Wide Range ◽  
Microbial Infections ◽  
Inorganic Mineral

Antibacterial materials based on calcium phosphates have wide range of biomedical applications in the prevention of microbial infections. The synthesis of inorganic mineral component of bone i.e. hydroxyapatite was done with the addition of silver (Ag) (5-15 wt %) as antibacterial agent. The wet precipitation synthesis was carried out using diammonium hydrogen phosphate and calcium nitrate as P and Ca precursors. The presence and effect of silver addition on the structure was studied using Fourier Transform-Infrared (FTIR) spectroscopy and Energy Dispersive X-ray (EDX) techniques. The antibacterial properties of all samples were evaluated using Disc Diffusion Technique (DDT) againstS. aureus,B. subtilis, P. aeruginosaandE. coli. Antibacterial activities of samples were found to vary depending on the bacterial species and Ag loading percentage. The antibacterial assay suggested that the addition of Ag ions within hydroxyapatite can be effectively provided the required level of antibacterial activity against bacteria.

scholarly journals A INFLUÊNCIA DA FÉ NO TRATAMENTO DE PACIENTES ONCOLÓGICOS

2021 ◽  
Vol 7 (2) ◽  
pp. 214-235
Author(s):  
Catia Almeida Alves da Silva ◽  
Karina Aparecida Ferreira da Rocha ◽  
Luiz Roberto Marquezi Ferro ◽  
Aislan José de Oliveira ◽  
Márcia Guimarães Rivas
Keyword(s):  
Treatment Process ◽  
Life Quality ◽  
Public Health Problem ◽  
Technical Knowledge ◽  
Hospital Unit ◽  
The People ◽  
Oncological Patients ◽  
Long Time ◽  
Trust And Power ◽  
Negative Feelings

The cancer has been studied for a long time and some conclusions of these illness should be associate of many reasons. According some researches, this illness has been considered one of the biggest public health problem around the world and with many cases registered. Everybody who is in front of possibility to positive diagnostic of cancer can be negative feelings or thoughts about the future and their uncertainties. The psychologist should contribute with the mental process by using technical knowledge to help people and mental impacts caused because the illness and contribute with a complete care identifying potentials psychical disorders. In this process the faith becomes a significant alternative to the treatment, could result in trust and power of balance. The faith should be represented part of a process to understand and take on lidding with the cancer, improving the life quality and intensifying the struggle of illness. The focus on this studying was identifying the influence of faith on oncological patients’ treatment on hospital unit in São Paulo from capital. It was about a qualitative research and were considered seven people with the same repetitive talks after had been interviewed. The people selection was random, inside the hospital and all of participants was interviewed following a guide prepared before of the researches. The analyses results were produced about the “Talk Analyses or Speech Analyses” making the categories. In terms of expected results, the faith was considered a positive alternative and source to face or to feel of cancer. The faith phenomenon can contribute significantly to the cancer treatment process.

scholarly journals In Search of the Optimal Conditions to Process Shape Memory Alloys (NiTi) Using Fused Filament Fabrication (FFF)

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4718
Author(s):  
Pedro Carreira ◽  
Fábio Cerejo ◽  
Nuno Alves ◽  
Maria Teresa Vieira
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Sintering Temperature ◽  
Production Costs ◽  
Layer By Layer ◽  
Secondary Phases ◽  
Fused Filament Fabrication ◽  
Near Net Shape ◽  
Niti Shape Memory Alloys

This research was performed so as to investigate the additive manufacturing of NiTi shape memory alloys, which is associated with direct processes, such as selective laser melting. In addition to its expensive production costs, NiTi readily undergoes chemical and phase modifications, mainly as a result of Ni loss during processing as a result of high temperatures. This research explores the potential usefulness of NiTi as well as its limitations using indirect additive processes, such as fused filament fabrication (FFF). The first step was to evaluate the NiTi critical powder volume content (CPVC) needed to process high-quality filaments (via extrusion). A typical 3D printer can build a selected part/system/device layer-by-layer from the filaments, followed by debinding and sintering (SDS), in order to generate a near-net-shape object. The mixing, extruding (filament), printing (shaping), debinding, and sintering steps were extensively studied in order to optimize their parameters. Moreover, for the sintering step, two main targets should be met, namely: the reduction of contamination during the process in order to avoid the formation of secondary phases, and the decrease in sintering temperature, which also contributes to reducing the production costs. This study aims to demonstrate the possibility of using FFF as an additive manufacturing technology for processing NiTi.

Ceramics based on calcium phosphates substituted with magnesium ions for bone regeneration

2019 ◽  
Vol 17 (1) ◽  
pp. 342-353 ◽  
Author(s):  
Cristina‐Daniela Ghițulică ◽  
Andreia Cucuruz ◽  
Georgeta Voicu ◽  
Andrei T. Cucuruz ◽  
Sorina Dinescu ◽  
...  
Keyword(s):  
Bone Regeneration ◽  
Calcium Phosphates ◽  
Magnesium Ions

Influence of calcium phosphates incorporation into poly(lactic-co-glycolic acid) electrospun membranes for guided bone regeneration

2020 ◽  
Vol 179 ◽  
pp. 109253
Author(s):  
Vivian Inês dos Santos ◽  
Claudia Merlini ◽  
Águedo Aragones ◽  
Karina Cesca ◽  
Márcio Celso Fredel
Keyword(s):  
Bone Regeneration ◽  
Glycolic Acid ◽  
Calcium Phosphates ◽  
Guided Bone Regeneration ◽  
Electrospun Membranes

Effect of Sintering Conditions on Translucency of High Translucent Zirconia

2019 ◽  
Vol 829 ◽  
pp. 49-53
Author(s):  
Hiroshi Kono ◽  
Hiroyuki Arikawa ◽  
Syunichi Hamamura ◽  
Yasuhiro Sonoda ◽  
Masafumi Kikuchi
Keyword(s):  
Firing Temperature ◽  
Sintering Temperature ◽  
New Products ◽  
Contrast Ratio ◽  
Heating Time ◽  
Heating Rates ◽  
Sintering Time ◽  
Long Time ◽  
Sintering Conditions ◽  
Rising Time

Sintering of zirconia usually takes a long time. In recent years, new products with extremely short sintering time have been released. Therefore, it is useful to study in detail the effect of sintering temperature and time on translucency of zirconia. The prepared discs were sintered under four conditions; 30 minutes, 40 minutes, 50 minutes and 60 minutes as firing temperature rising time up to 1500°C. Samples were measured with a spectrophotometer and translucency parameter (TP), opalescence parameter (OP) and contrast ratio (CR) were calculated. In this study, there were no statistically significant differences between TP, OP and CR due to the differences in heating rates. There is a possibility that a heating time up to the sintering temperature does not affect translucency of zirconia.

Synthesis of Zn0.2Ca0.8TiO3:0.1Pr3+ by Sol-Gel and its Luminescence Characterization

2013 ◽  
Vol 750-752 ◽  
pp. 877-880
Author(s):  
Yi Shen ◽  
Li Ying Han ◽  
Lu Yao Hou
Keyword(s):  
Treatment Process ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Ultra Violet ◽  
Luminescent Properties ◽  
Luminescent Materials ◽  
Excitation Spectra ◽  
Surface Appearance ◽  
Calcination Temperatures ◽  
Characteristic Emission

The Zn0.2Ca0.8TiO3:0.1Pr3+ luminescent materials were prepared by sol-gel technology. The phase transformation of gel was studied by TG-DTA and XRD in heat treatment process. The luminescent properties of phosphor in different calcination temperatures were determined by fluorescence spectrophotometer, and then the best sintering temperature was confirmed. The luminescent properties of phosphor was obtained through the emission/ excitation spectra. The surface appearance measured with SEM. The results showed that the nanoZn0.2Ca0.8TiO3:0.1Pr3+ phosphor could be obtained by sol-gel, sintering at 900°C. It sent out red fluorescent under the Ultra Violet. This characteristic emission peak at 614nm is associated with the typical 1D23H4 transition of Pr3+ion.

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