scholarly journals Sintering Behavior and Mechanical Properties of Biphasic Calcium Phosphate Ceramics

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Mehmet Yetmez
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Calcium Phosphate ◽  
Grain Growth ◽  
Vickers Hardness ◽  
Tricalcium Phosphate ◽  
Biphasic Calcium Phosphate ◽  
Sintering Temperature ◽  
Sintering Behavior ◽  
Microstructure Observation

The sintering behavior and the mechanical properties of a mechanical mixture of hydroxyapatite and tricalcium phosphate (BCP) ceramics with the composition of 30% HA and 70% TCP are experimentally investigated in the temperature range between 1000°C and 1300°C. The results show that consolidation, grain growth, and Vickers hardness generally increase with increasing sintering temperature up to 1200°C. However, microstructure observation indicates that cracks are formed along the grain boundaries as well as in the bulk of the grains after sintering at 1200°C. Moreover, the best values of compressive strength, modulus of elasticity, and toughness are achieved in the samples sintered at 1100°C. These properties at 1100°C decay with sintering at 1200°C and increase again after sintering at 1300°C.

Fabrication of α-Tricalcium Phosphate Ceramics through Two-Step Sintering

2014 ◽  
Vol 631 ◽  
pp. 78-82 ◽  
Author(s):  
Ill Yong Kim ◽  
Jian Wen ◽  
Chikara Ohtsuki
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Calcium Phosphate ◽  
Cortical Bone ◽  
Grain Growth ◽  
Tricalcium Phosphate ◽  
Porous Body ◽  
Physiological Condition ◽  
Dense Body ◽  
Conventional Sintering

α-tricalcium phosphate (α-TCP), which shows higher solubility than β-TCP, is bioabsorbable and receives special attention for its ability of turning into hydroxyapatite (HAp) in a physiological condition. Problems occasionally occur as α-TCP porous body is too brittle to be handled. Compressive strengths of β-TCP and HAp dense sintered blocks are reported to be comparable to that of human cortical bone. However, α-TCP dense body has rarely been reported. For fabrication of dense sintered body, two-step sintering (TSS) was applied in this study. The TSS generally has firing processes at the lower temperatures, following that at the higher temperatures. TSS is known as one of most effective processing to prevent grain growth comparing with conventional sintering (CS). Dense body of α-TCP was fabricated by both CS and TSS. TSS processing involves heating specimens to T1 temperature, followed by holding at a relatively lower T2 temperature for 12 h. Microstructures of the sintered bodies were characterized and mechanical properties were also evaluated. The specimen prepared by TSS processing with T1 1400 °C, T2 1300 °C showed the lowest porosity (2.7%) and highest compressive strength (714 MPa) among the prepared specimens. TSS processing might be applicable on densification of calcium phosphate powders to fabricate dense body.

Effect of Sintering Temperature on Biphasic Calcium Phosphate (BCP) Biocomposite

2015 ◽  
Vol 1087 ◽  
pp. 475-478 ◽  
Author(s):  
Shah Rizal Kasim ◽  
Nor Firdaus Muhamad ◽  
Sivakumar Ramakrishan
Keyword(s):  
Calcium Phosphate ◽  
Mathematical Models ◽  
Design Of Experiment ◽  
Tricalcium Phosphate ◽  
Biphasic Calcium Phosphate ◽  
Sintering Temperature ◽  
Present Report ◽  
Tcp Phases ◽  
Different Temperatures ◽  
Formation Porosity

The present report aims to fabricate biphasic calcium phosphate (BCP) biocomposite in order to study the effects of sintering temperature on the sintered BCP biocomposite characteristics (phase’s formation, porosity and hardness properties). These effects were quantified using design of experiment (DOE) to develop mathematical models. BCP biocomposite pellets (60 wt% HA) were fabricated using mixing, pressing and sintered at two different temperatures (1100°C and 1250°C). The experiment was run by following the run order suggested by DOE software (Minitab 16) through randomization stage. Results show that sintering temperature will affect the formation of α-tricalcium phosphate (α-TCP) and the porosity of the samples. The formation of α-TCP phases will reduce the hardness value of BCP biocomposite.

Surface Characteristics and Osteoinductivity of Biphasic Calcium Phosphate Ceramics with Different Sintering Temperature

2006 ◽  
Vol 309-311 ◽  
pp. 1299-1302 ◽  
Author(s):  
Hong Song Fan ◽  
Toshiyuki Ikoma ◽  
C.Y. Bao ◽  
H.L. Wang ◽  
Ling Li Zhang ◽  
...  
Keyword(s):  
Phase Composition ◽  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Biphasic Calcium Phosphate ◽  
Sintering Temperature ◽  
Surface Characteristics ◽  
Affecting Factors ◽  
Micro Structure ◽  
Factors Affecting ◽  
Distinct Temperature

Calcium phosphate (Ca-P) biomaterials have been proved to show osteoinductivity, however the affecting factors and mechanism are still unclear now. In this study, the surface characteristics of biphasic Ca-P ceramics (hydroxyapatite/tricalcium phosphate; HA/TCP) sintered at the distinct temperature were investigated and the mechanism of the osteoinductivity was discussed. The osteoinductivity of HA/TCP ceramics increased with decreasing the sintering temperature. The different surface micro-structure resulted from different sintering temperature includes phase composition, surface micro-structure, and surface potential. These characteristics should be the important factors affecting osteoinductivity.

Sintering of cubic boron nitride without additives at 7.7 GPa and above 2000 °C

1999 ◽  
Vol 14 (1) ◽  
pp. 162-169 ◽  
Author(s):  
Takashi Taniguchi ◽  
Minoru Akaishi ◽  
Shinobu Yamaoka
Keyword(s):  
Fracture Toughness ◽  
Boron Nitride ◽  
Grain Growth ◽  
Sintering Temperature ◽  
Cubic Boron Nitride ◽  
Sintering Behavior ◽  
Particle Sizes ◽  
Fine Powders ◽  
Microstructure Observation

The sintering behavior of cBN powder with various particle sizes from 0.5 to 12 µm was investigated when sintered at temperatures from 1500 to 2500 °C and pressure of 7.7 GPa without additives. Above 2000 °C, translucent sintered bodies were obtained. Microstructure observation indicated that the optimum sintering temperature was near 2350 °C for fine powders of 0.5 to 1.2 µm and 2 to 4 µm, and slightly higher than 2350 °C for powders from 8 to 12 µm. The fracture toughness of the well-sintered bodies decreased with grain growth above the optimum sintering temperature.

Processing and Mechanical Properties of Biphasic Calcium-Phosphate/Poly-L-Lactide Composite Biomaterials

2004 ◽  
Vol 471-472 ◽  
pp. 273-277
Author(s):  
Chak Yin Tang ◽  
N. Ignjatović ◽  
Dragan P. Uskokovic ◽  
P.S. Uskoković ◽  
K.C. Chan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Calcium Phosphate ◽  
Cortical Bone ◽  
Hot Pressing ◽  
Biphasic Calcium Phosphate ◽  
Wide Angle ◽  
Compression Tests ◽  
Temperature Range ◽  
Pressing Time

This study descripts processing of biphasic calcium-phosphate (BCP) and poly-L-lactide (PLLA) biocomposite implant material. The composite was obtained by mixing completely dissolved PLLA with granules of high crystalline BCP and was compacted by hot pressing using cylindrical dies at 450 K temperature and 98.1 MPa pressure, for 30 and 60 minutes. Wide-angle Xray structural (WAXS) analyses of BCP, PLLA and BCP/PLLA composite blocks were made followed by calorimetric (DSC) tests in the 320-520 K temperature range. Compression tests revealed that Young’s modulus and compressive strength of the composite increased with extended hot pressing time and were found to be within the bounds of the cortical bone values.

The Sintering Behaviour and Mechanical Properties of Hydroxyapatite - Based Composites for Bone Tissue Regeneration

2018 ◽  
Vol 69 (5) ◽  
pp. 1272-1275 ◽  
Author(s):  
Camelia Tecu ◽  
Aurora Antoniac ◽  
Gultekin Goller ◽  
Mustafa Guven Gok ◽  
Marius Manole ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tricalcium Phosphate ◽  
Cosmetic Surgery ◽  
Mechanical Stability ◽  
Raw Materials ◽  
Oyster Shell ◽  
Bone Tissue Regeneration ◽  
Sintering Behavior ◽  
Bovine Bone ◽  
Human Teeth

Bone reconstruction is a complex process which involves an osteoconductive matrix, osteoinductive signaling, osteogenic cells, vascularization and mechanical stability. Lately, to improve the healing of the bone defects and to accelerate the bone fusion and bone augmentation, bioceramic composite materials have been used as bone substitutes in the field of orthopedics and dentistry, as well as in cosmetic surgery. Of all types of bioceramics, the most used is hydroxyapatite, because of its similar properties to those of the human bone and better mechanical properties compared to b-tricalcium phosphate [1]. Currently, the most used raw materials sources for obtaining the hydroxyapatite are: bovine bone, seashells, corals, oyster shell, eggshells and human teeth. There are two common ways to obtain hydroxyapatite: synthetically and naturally. Generally, for the improvement of the mechanical properties and the structural one, hydroxyapatite is subjected to the sintering process. Considering the disadvantages of hydroxyapatite such as poor biodegradation rate, b-TCP has been developed, which has some disadvantages too, such as brittleness. For this reason, the aim of this study is to look into the effect of adding magnesium oxide on the sintering behavior, the structure and the mechanical properties of the hydroxyapatite-tricalcium phosphate composites.

scholarly journals The preparation and application of calcium phosphate biomedical composites in filling of weight-bearing bone defects

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lijia Cheng ◽  
Tianchang Lin ◽  
Ahmad Taha Khalaf ◽  
Yamei Zhang ◽  
Hongyan He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Weight Bearing ◽  
Bone Defects ◽  
Type I ◽  
Artificial Bone ◽  
Thermosensitive Hydrogel ◽  
Bone Repairing ◽  
Histological Staining

AbstractNowadays, artificial bone materials have been widely applied in the filling of non-weight bearing bone defects, but scarcely ever in weight-bearing bone defects. This study aims to develop an artificial bone with excellent mechanical properties and good osteogenic capability. Firstly, the collagen-thermosensitive hydrogel-calcium phosphate (CTC) composites were prepared as follows: dissolving thermosensitive hydrogel at 4 °C, then mixing with type I collagen as well as tricalcium phosphate (CaP) powder, and moulding the composites at 37 °C. Next, the CTC composites were subjected to evaluate for their chemical composition, micro morphology, pore size, Shore durometer, porosity and water absorption ability. Following this, the CTC composites were implanted into the muscle of mice while the 70% hydroxyapatite/30% β-tricalcium phosphate (HA/TCP) biomaterials were set as the control group; 8 weeks later, the osteoinductive abilities of biomaterials were detected by histological staining. Finally, the CTC and HA/TCP biomaterials were used to fill the large segments of tibia defects in mice. The bone repairing and load-bearing abilities of materials were evaluated by histological staining, X-ray and micro-CT at week 8. Both the CTC and HA/TCP biomaterials could induce ectopic bone formation in mice; however, the CTC composites tended to produce larger areas of bone and bone marrow tissues than HA/TCP. Simultaneously, bone-repairing experiments showed that HA/TCP biomaterials were easily crushed or pushed out by new bone growth as the material has a poor hardness. In comparison, the CTC composites could be replaced gradually by newly formed bone and repair larger segments of bone defects. The CTC composites trialled in this study have better mechanical properties, osteoinductivity and weight-bearing capacity than HA/TCP. The CTC composites provide an experimental foundation for the synthesis of artificial bone and a new option for orthopedic patients.

Effect of TiO2 and MgO on Microstructure of α-Alumina Ceramics and its Sintering Behavior

2015 ◽  
Vol 1112 ◽  
pp. 519-523 ◽  
Author(s):  
Jarot Raharjo ◽  
Sri Rahayu ◽  
Tika Mustika ◽  
Masmui ◽  
Dwi Budiyanto
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Physical And Mechanical Properties ◽  
Basic Material ◽  
Sintering Behavior ◽  
Pressureless Sintering ◽  
Alumina Ceramics ◽  
Density Measurements ◽  
Technical Alumina ◽  
Platelet Structure

Observation on the effect of adding titanium oxide (TiO2) and magnesium oxide (MgO) on the sintering of α-alumina (Al2O3) has been performed. In this study, technical alumina used as basic material in which the sample is formed by the pressureless sintering/cold press and sintered at 1500°C which is lower than alumina sintering temperature at 1700°C. Elemental analysis, observation of microstructure, hardness, fracture toughness and density measurements were carried out to determine the physical and mechanical properties of alumina. The results indicate a change in the microstructure where the content of the platelet structure are much more than the equilateral structure. At sintering temperature of 1500°C, neck growth occurs at ceramics grain, supported by the results of the density test which indicate perfect compaction has occurred in this process.

Synthesis of Alpha-Tricalcium Phosphate by Wet Reaction and Evaluation of Mechanical Properties

2012 ◽  
Vol 727-728 ◽  
pp. 1164-1169 ◽  
Author(s):  
Mônica Beatriz Thürmer ◽  
Rafaela Silveira Vieira ◽  
Juliana Machado Fernandes ◽  
Wilbur Trajano Guerin Coelho ◽  
Luis Alberto Santos
Keyword(s):  
Mechanical Properties ◽  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Calcium Nitrate ◽  
Chemical Precipitation ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Phosphate Cements

Calcium phosphate cements have bioactivity and osteoconductivity and can be molded and replace portions of bone tissue. The aim of this work was to study the obtainment of α-tricalcium phosphate, the main phase of calcium phosphate cement, by wet reaction from calcium nitrate and phosphoric acid. There are no reports about α-tricalcium phosphate obtained by this method. Two routes of chemical precipitation were evaluated and the use of two calcinations temperatures to obtain the phase of cement. The influence of calcination temperature on the mechanical properties of cement was evaluated. Cement samples were characterized by particle size analysis, X-ray diffraction, mechanical strength and scanning electron microscopy. The results demonstrate the strong influence of synthesis route on the crystalline phases of cement and the influence of concentration of reactants on the product of the reaction, as well as, on the mechanical properties of cement.

The Fabricated Collagen-Based Nano-Hydroxyapatite/β-Tricalcium Phosphate Scaffolds

2012 ◽  
Vol 506 ◽  
pp. 57-60 ◽  
Author(s):  
M. Ebrahimi ◽  
Naruporn Monmaturapoj ◽  
S. Suttapreyasri ◽  
P. Pripatnanont
Keyword(s):  
Mechanical Properties ◽  
Solid State ◽  
Calcium Phosphate ◽  
Biphasic Calcium Phosphate ◽  
Single Phase ◽  
Physical And Mechanical Properties ◽  
Total Porosity ◽  
Xrd Pattern ◽  
Collagen Coating ◽  
Dimensional Shrinkage

The biphasic calcium phosphate (BCP) concept was introduced to overcome disadvantages of single phase biomaterials. In this study, we prepared BCP from nanoHA and β-TCP that were synthesized via a solid state reaction. Three different ratios of pure BCP and collagen-based BCP scaffolds (%HA/%β-TCP; 30/70, 40/60 and 50/50) were produced using a polymeric sponge method. Physical and mechanical properties of all materials and scaffolds were investigated. XRD pattern proved the purity of each HA, β-TCP and BCP. SEM showed overall distribution of macropores (80-200 µm) with appropriate interconnected porosities. Total porosity of pure BCP (93% ± 2) was found to be higher than collagen-based BCP (85%± 3). It was observed that dimensional shrinkage of larger scaffold (39% ± 4) is lower than smaller one (42% ± 5) and scaffolds with higher HA (50%) ratio experienced greater shrinkage than those with higher β-TCP (70%) ratio (45% ±3 and 36% ±1 respectively). Mechanical properties of both groups tend to be very low and collagen coating had no influence on mechanical behavior. Further studies may improve the physical properties of these composite BCP.

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