scholarly journals Evaluation of Structural and Mechanical Properties of Porous Artificial Bone Scaffolds Fabricated via Advanced TBA-Based Freeze-Gel Casting Technique

2019 ◽  
Vol 9 (9) ◽  
pp. 1965 ◽  
Author(s):  
Tae-Rim Kim ◽  
Min-Su Kim ◽  
Tae Sik Goh ◽  
Jung Sub Lee ◽  
Yun Hak Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cancellous Bone ◽  
Casting Process ◽  
High Porosity ◽  
Artificial Bone ◽  
Porous Hydroxyapatite ◽  
Casting Technique ◽  
Bone Scaffolds ◽  
Gel Casting

Porous hydroxyapatite (HA) artificial bone scaffolds were prepared via the freeze-gel casting process in order to improve their mechanical strengths. As a porogen, various volumes of poly (methyl methacrylate) (PMMA) powders were added to obtain high porosity, such as in cancellous bone. After fabrication, the porous and mechanical properties of the scaffolds were examined. The HA60 scaffold, with a porosity over 80%, had proper compressive strength and modulus and satisfied the range of properties of cancellous bone. Moreover, it was found that the investigated mechanical properties were affected by the scaffolds’ porosity. However, a section was found where the compressive strength was high despite the increase in the porosity. Specifically, HA30 had a porosity of 62.9% and a compressive strength of 1.73 MPa, whereas the values for HA60 were 81.9% and 3.23 MPa, respectively. The results indicate that there are factors that can preserve the mechanical properties even if the porosity of the scaffold increases. Therefore, in this study, various parameters affecting the porous and mechanical properties of the scaffolds during the manufacturing process were analyzed. It is expected that the improvement in the mechanical properties of the artificial bone scaffold having a high porosity can be applied to tissue engineering.

Preparation of Porous Hydroxyapatite-Zirconia Composite Scaffolds by Combination of Gel-Casting and Polymer Sponge Methods

2010 ◽  
Vol 105-106 ◽  
pp. 616-619 ◽  
Author(s):  
Li Li Wang ◽  
Xiu Feng Wang ◽  
Hong Tao Jiang ◽  
Cheng Long Yu
Keyword(s):  
Compressive Strength ◽  
Electron Microscope ◽  
Porous Structure ◽  
Porous Scaffolds ◽  
Pore Morphology ◽  
Porous Composite ◽  
Composite Scaffolds ◽  
Porous Hydroxyapatite ◽  
Casting Technique ◽  
Gel Casting

Hydroxyapatite (HA) doped with 3%yttria-stabilized 20wt% zirconia (ZrO2) ceramic were developed in order to produce a porous composite biomaterial by integrating the gel-casting technique with polymer sponge method with improved mechanical strength and controllable porous structure. The pore morphology, size, and distribution of the scaffolds were characterized using an electron microscope. The scaffolds prepared have an open, uniform and interconnected porous structure with a pore size of 300~500m. The porosity of the open pores in the scaffold can be controlled by changing HA-ZrO2 composite concentration and it is between 87%~35%. A compressive strength of 12MPa for HA-ZrO2 porous scaffolds with HA-ZrO2 concentration of 55wt% was achieved, which is comparable to that of cortical bone.

Comparison of Porous Ti6Al4V Made by Sponge Replication and Directly 3D Fiber Deposition and Cancellous Bone

2007 ◽  
Vol 330-332 ◽  
pp. 999-1002 ◽  
Author(s):  
J.P. Li ◽  
J.R. Wijn ◽  
Clemens A. van Blitterswijk ◽  
K. de Groot
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Structure ◽  
Cancellous Bone ◽  
Structure And Properties ◽  
Porous Ti ◽  
Fiber Deposition ◽  
Regular Open

The present investigation gives a comparison of the structure and properties of porous Ti6Al4V made by sponge replication (Sponge Ti) and directly 3D fiber deposition (D3DF Ti) and cancellous bone. Although the macrostructure of these two materials differs, their microstructure seems to be similar. Both scaffolds reveal an open pore structure, while D3DF Ti shows a fairly regular open pore structure, sponge Ti6Al4V exhibit an irregular open pore structure similar to that of cancellous bone. The mechanisms resulting in mechanical properties like stiffness or strength are, accordingly, different. The compressive strength and E’ modulus of Ti6Al4V scaffold are higher than that of cancellous bone,. The permeability results show both Ti6Al4V scaffolds are quite comparable with cancellous bone.

Microstructure and mechanical properties of hydroxyapatite obtained by gel-casting process

2008 ◽  
Vol 34 (2) ◽  
pp. 359-364 ◽  
Author(s):  
Biqin Chen ◽  
Tao Zhang ◽  
Jingxian Zhang ◽  
Qingling Lin ◽  
Dongliang Jiang
Keyword(s):  
Mechanical Properties ◽  
Casting Process ◽  
Gel Casting ◽  
Microstructure And Mechanical Properties

Porous hydroxyapatite scaffolds containing calcium phosphate glass-ceramics processed using a freeze/gel-casting technique

2014 ◽  
Vol 20 (1) ◽  
pp. 135-140 ◽  
Author(s):  
Tae Wan Kim ◽  
Su Chak Ryu ◽  
Byung Kyu Kim ◽  
Seog Young Yoon ◽  
Hong Chae Park
Keyword(s):  
Calcium Phosphate ◽  
Phosphate Glass ◽  
Glass Ceramics ◽  
Porous Hydroxyapatite ◽  
Casting Technique ◽  
Gel Casting

scholarly journals Behavior of Steel Slag Concrete Subjected to Elevated Temperature

2020 ◽  
Vol 9 (4) ◽  
pp. 1165-1170
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Coarse Aggregate ◽  
Steel Slag ◽  
Partial Replacement ◽  
High Porosity ◽  
Residual Mechanical Properties

Recycling of materials has become a major interest for engineers. At present, the amount of slag deposited in storage yard adds up to millions of tons/year leading to the occupation of farm land and serious pollution to the environment, as a result of the rapid growth in the steel industry. Steel slag is made at 1500- 1650°C having a honey comp shape with high porosity. Using steel slag as the natural aggregate with a lower waste material cost can be considered as a good alternative for sustainable constructions. The objective of this study is to evaluate the performance of residual mechanical properties of concrete with steel slag as coarse aggregate partial replacement after exposing to high temperatures .This study investigates the behavior of using granulated slag as partial or fully coarse aggregate replacement with different percentages of 0%, 15%, 30%, 50% and 100% in concrete when subjected to elevated temperatures. Six groups of concrete mixes were prepared using various replacement percentages of slag exposed to different temperatures of 400 °C, 600 °C and 800 °C for different durations of 1hr, 1.5hr and 2hr. Evaluation tests were compressive strength, tensile strength, and bond strength. The steel slag concrete mixes showed week workability lower than control mix. A systematic increasing of almost up to 21.7% in compressive strength, and 66.2% in tensile strength with increasing the percentage of steel slag replacement to 50%. And the results showed improvement on concrete residual mechanical properties after subjected to elevated temperatures with the increase of steel slag content. The findings of this study give an overview of the effect of steel slag coarse aggregate replacement on concrete after exposed to high temperatures.

scholarly journals Sinterability of Magnesium Hydroxyapatite Bioceramic and Its Mechanical Properties

2018 ◽  
Vol 7 (3.11) ◽  
pp. 197
Author(s):  
Syakir Ramli ◽  
Mardziah Che Murad ◽  
Nik Rozlin Nik Masdek
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Compressive Strength ◽  
Organic Compounds ◽  
Sintering Temperature ◽  
Precipitation Method ◽  
Artificial Bone ◽  
Lower Strength ◽  
Similar Composition ◽  
Dense Bodies

One of the most favoured material in bone tissue engineering field nowadays is hydroxyapatite (HA), which is also known to be bioactive and has a similar composition to human bone. However, developing an artificial bone or bone graft using biocompatible HA is a challenging task due to the lower strength of the main substance. To improve the mechanical properties of synthetic HA, introduction of metallic substance such as magnesium (Mg) into HA has been proposed. In this present study, 0, 10 15 wt% of magnesium hydroxyapatite (MgHA) nanopowders were prepared by a simple wet precipitation method. These nanopowders were then compacted using a 10-ton compression uniaxial press machine with 150 MPa pressure to form a disc shape of dense MgHA. After that, the MgHA discs were sintered at a temperature of 1000 °C and 1100 °C to remove the organic compounds and further densify the ceramics. XRD results showed that the crystallinity of MgHA increased when the sintering temperature increases. The compression test showed that the 10 wt% MgHA sample recorded the highest compressive strength (243.59 MPa) when sintered at 1100 °C, while pure HA has the lowest value with 49.37 MPa. This study also demonstrates that sintering temperature at 1100 °C gives significant improvement to the mechanical properties of the MgHA dense bodies compared to sintering at 1000 °C.  

scholarly journals Study on mechanical properties and permeability of elliptical porous scaffold based on the SLM manufactured medical Ti6Al4V

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247764
Author(s):  
Chenglong Shi ◽  
Nana Lu ◽  
Yaru Qin ◽  
Mingdi Liu ◽  
Hongxia Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Pore Size ◽  
Cancellous Bone ◽  
Simulation Analysis ◽  
Porous Scaffold ◽  
Angle Distribution ◽  
Artificial Bone ◽  
Mechanical Compression ◽  
Human Cancellous Bone ◽  
Computational Fluid Dynamics Cfd

In this paper, we take the elliptical pore structure which is similar to the microstructure of cancellous bone as the research object, four groups of bone scaffolds were designed from the perspective of pore size, porosity and pore distribution. The size of the all scaffolds were uniformly designed as 10 × 10 × 12 mm. Four groups of model samples were prepared by selective laser melting (SLM) and Ti6Al4V materials. The statics performance of the scaffolds was comprehensively evaluated by mechanical compression simulation and mechanical compression test, the manufacturing error of the scaffold samples were evaluated by scanning electron microscope (SEM), and the permeability of the scaffolds were predicted and evaluated by simulation analysis of computational fluid dynamics (CFD). The results show that the different distribution of porosity, pore size and pores of the elliptical scaffold have a certain influence on the mechanical properties and permeability of the scaffold, and the reasonable size and angle distribution of the elliptical pore can match the mechanical properties and permeability of the elliptical pore scaffold with human cancellous bone, which has great potential for research and application in the field of artificial bone scaffold.

Influence of Fabricated Process on Mechanical Properties of Porous SiC-Particle/Si3N4 Composites

2007 ◽  
Vol 336-338 ◽  
pp. 1320-1323 ◽  
Author(s):  
Hong Jie Wang ◽  
Wen Zhang ◽  
Yu Bai ◽  
Guan Jun Qiao ◽  
Ji Qiang Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Powder Compact ◽  
High Strength ◽  
Uniform Structure ◽  
High Porosity ◽  
Gel Casting ◽  
N2 Atmosphere ◽  
Porous Sic ◽  
Sic Particle

In this paper, the mechanical properties of porous Si3N4/SiC composite prepared by different forming method (uniaxial pressing and gel-casting) were compared. Using gelcasting and two steps sintering technology, the porous SiC-particle/Si3N4 composites with a high strength, uniform structure and a relative high porosity were obtained by adding a little amount of nano carbon in slurry. The flexural strength of optimized material reaches to 100MPa and its porosity is more than 60%. But using uniaxial pressing and sintering at N2 atmosphere, because the green bodies have the high density, and the density distribution of a powder compact was not uniform, the flexural strength is not high, and at the same time, the microstructure is not uniform also.

Evaluation and Control of Crack Propagation in Dense Porcelain/ Porous Alumina Layered Structures for Dental Material Applications

2006 ◽  
Vol 317-318 ◽  
pp. 457-460 ◽  
Author(s):  
Jae Won Kim ◽  
Seong Hwan Park ◽  
Yeon Gil Jung ◽  
Hee Soo Lee
Keyword(s):  
Crack Propagation ◽  
Buffer Layer ◽  
Porous Alumina ◽  
Casting Process ◽  
Layered Structures ◽  
Alumina Powder ◽  
High Porosity ◽  
Gel Casting ◽  
And Control ◽  
Layered Samples

Layered structures of dense porcelain/porous alumina and dense porcelain/porcelainalumina/ porous alumina are designed and their crack propagation behaviors are investigated. As a substrate, the porous alumina, which is prepared by a gel-casting process using the binary slip of alumina powder and PMMA spherical micro-bead, is dried at room temperature for 24 h and then sintered at 1600 for 2 h. Porcelain is coated on the porous alumina substrate and then re-sintered at 987. Bi- and tri-layered structures are produced by the different dwell times (2 min, 10 min) at re-sintering temperature. There is no delaminating or cracks observed after re-sintering the layered samples. The crack propagation behaviors in the bi- and tri-layered structures are evaluated by micro-indentation. The indentation cracks do not propagate into the porous alumina through interface (porosity; 36~62%) except for another one (porosity; 70%) in the bi-layered samples. In the case of the high porosity bi-layered sample (porosity; 70%), cracks are scattered along the 3-D open-pore channels. However, cracks do not propagate through the interface in the tri-layered samples with a porcelain-alumina buffer layer, because the porcelain-alumina buffer layer plays an important part such as a barrier layer in crack propagation.

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