Mechanical Properties of Micro-Porous Metals Produced by Space-Holding Sintering

2007 ◽  
Vol 29-30 ◽  
pp. 75-78 ◽  
Author(s):  
Takumi Banno ◽  
Yun Cang Li ◽  
Cui E Wen ◽  
Yasuo Yamada
Keyword(s):  
Mechanical Properties ◽  
Cell Structure ◽  
Deformation Behaviour ◽  
Average Pore Size ◽  
Chemical Vapour ◽  
Porous Nickel ◽  
Porous Metals ◽  
Average Pore ◽  
Nickel Foams ◽  
Compressive Tests

Micro-porous nickel foams with an open cell structure were fabricated by the space-holding sintering. The average pore size of the micro-porous nickel specimens ranged from 30 μm to 150 μm, and the porosity ranged from 60 % to 80 %. The porous characteristics of the nickel specimens were observed using scanning electron microscopy (SEM). The mechanical properties were studied using compressive tests. For comparison, macro-porous nickel foams prepared by the chemical vapour deposition method with pore sizes of 800 μm and 1300 μm and porosity of 95 % were also presented. Results indicated that the ratio value of 6 and higher for the specimen length to cell size (L/d) is satisfying for obtaining stable compressive properties. The micro-porous nickel specimens exhibited different deformation behaviour and dramatically increased mechanical properties, compared to those of the macro-porous nickel specimens.

Micro-Porous Nickel Produced by Powder Metallurgy

2007 ◽  
Vol 534-536 ◽  
pp. 977-980
Author(s):  
Yasuo Yamada ◽  
Yun Cang Li ◽  
Takumi Banno ◽  
Zhen Kai Xie ◽  
Cui E Wen
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Porous Structure ◽  
Pore Size ◽  
Cell Structure ◽  
Deformation Behaviour ◽  
Average Pore Size ◽  
Chemical Vapour ◽  
Porous Nickel ◽  
Average Pore

Micro-porous nickel (Ni) with an open cell structure was fabricated by a special powder metallurgical process, which includes the adding of a space-holding material. The average pore size of the micro-porous Ni samples approximated 30 μm and 150 μm, and the porosity ranged from 60 % to 80 %. The porous characteristics of the Ni samples were observed using scanning electron microscopy (SEM) and the mechanical properties were evaluated using compressive tests. For comparison, porous Ni samples with a macro-porous structure prepared by both powder metallurgy (pore size 800 μm) and the traditional chemical vapour deposition (CVD) method (pore size 1300 μm) were also presented. Results indicated that the porous Ni samples with a micro-porous structure exhibited different deformation behaviour and dramatically increased mechanical properties, compared to those of the macro-porous Ni samples.

Preparation and Characterisation of Open-Cell Microporous Nickel

2007 ◽  
Vol 539-543 ◽  
pp. 1833-1838 ◽  
Author(s):  
Yasuo Yamada ◽  
Takumi Banno ◽  
Zhen Kai Xie ◽  
Yun Cang Li ◽  
Cui E Wen
Keyword(s):  
Mechanical Properties ◽  
Pore Size ◽  
Average Pore Size ◽  
Microporous Structure ◽  
Macroporous Structure ◽  
Average Pore ◽  
Open Cell ◽  
Nickel Foams ◽  
Sintering Method ◽  
Compressive Tests

In the present study, nickel foams with an open cell microporous structure were fabricated by the so-called space-holding particle sintering method, which included the adding of a particulate polymeric material (PMMA). The average pore size of the nickel foams approximated 10.5 μm; and the porosity ranged from 70 % to 80 %. The porous characteristics of the nickel foams were observed using scanning electron microscopy and the mechanical properties were evaluated using compressive tests. For comparison, nickel foams with an open-cell macroporous structure (pore size approximately 1.3 mm) were also presented. Results indicated that the nickel foams with a microporous structure possess enhanced mechanical properties than those with a macroporous structure.

Anisotropic Mechanical Properties of Nickel Foams Fabricated by Powder Metallurgy

2008 ◽  
Vol 569 ◽  
pp. 277-280
Author(s):  
Yasuo Yamada ◽  
Takumi Banno ◽  
Yun Cang Li ◽  
Cui E Wen
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Pore Size ◽  
Nickel Foam ◽  
Deformation Behaviour ◽  
Nominal Stress ◽  
Porous Nickel ◽  
Anisotropic Mechanical Properties ◽  
Electron Scanning Microscopy ◽  
Nickel Foams

In the present study, porous nickel foam samples with pore sizes of 20 μm and 150 μm and porosities of 60 % and 70 % were fabricated by the space-holding sintering method via powder metallurgy. Electron scanning microscopy (SEM) and Image-Pro Plus were used to characterise the morphological features of the porous nickel foam samples. The anisotropic mechanical properties of porous nickel foams were investigated by compressive testing loading in different directions, i.e. the major pore axis and minor pore axis. Results indicated that the nominal stress of the nickel foam samples increases with the decreasing of the porosity. Moreover, the foam sample exhibited significantly higher nominal stress for loading in the direction of the major pore axis than loading in direction of the minor pore axis. It is also noticeable that the nominal stress of the nickel foams increases with the decreasing of the pore size. It seems that the deformation behaviour of the foams with a pore size in the micron-order differs from those with a macro-porous structure.

scholarly journals Physicochemical and Mechanical Properties of Blow Spun Nanofibrous Prostheses Modified with Acrylic Acid and REDV Peptide

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1110
Author(s):  
Beata A. Butruk-Raszeja ◽  
Aleksandra Kuźmińska ◽  
Michał Wojasiński ◽  
Zuzanna Piotrowska
Keyword(s):  
Mechanical Properties ◽  
Fiber Diameter ◽  
Flow System ◽  
Average Pore Size ◽  
Internal Diameter ◽  
Optimal Parameters ◽  
Average Pore ◽  
Vascular Prostheses ◽  
Modification Process ◽  
Inner Surface

The paper presents a method of modifying the inner surface of nanofibrous vascular prostheses. The modification process involves two steps: introducing a hydrophilic linker, followed by a peptide containing the arginine-glutamic acid-aspartic acid-valine (REDV) sequence. The influence of the process parameters (reaction time, temperature, initiator concentration) on morphology and the distribution of fiber diameters were examined. For selected optimal parameters, the prostheses were modified in the flow system. Modifications along the entire length of the prosthesis were confirmed—the inlet and the outlet areas showed no significant (p > 0.05) differences in the value of the contact angle and the analyzed morphological parameters. The basic physicochemical and mechanical properties of modified prostheses were analyzed. The study showed that REDV-modified prosthesis has an average fiber diameter of 318 ± 99 nm, the average pore size of 3.0 ± 1.6 μm, the porosity of 48.4 ± 8.6% and Young’s modulus of 4.0 ± 0.4 MPa. The internal diameter of prostheses remains unchained and amounts to 3 mm. Such modified prostheses can reduce the risk of blood coagulation by increasing the surface’s wettability and, most of all, by introducing endothelial cell-selective peptide. As an effect, the proposed surfaces could recruit endothelial progenitor cells directly from the bloodstream and promote the endothelium formation after implantation.

scholarly journals Alginate/Gelatin Hydrogels Reinforced with TiO2 and β-TCP Fabricated by Microextrusion-based Printing for Tissue Regeneration

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 457 ◽  
Author(s):  
Rodrigo Urruela-Barrios ◽  
Erick Ramírez-Cedillo ◽  
A. Díaz de León ◽  
Alejandro Alvarez ◽  
Wendy Ortega-Lara
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Tissue Regeneration ◽  
Average Pore Size ◽  
Three Dimensional ◽  
Engineering Applications ◽  
Average Pore ◽  
Viscous Deformation ◽  
Freeze Dried ◽  
3D Printed

Three-dimensional (3D) printing technologies have become an attractive manufacturing process to fabricate scaffolds in tissue engineering. Recent research has focused on the fabrication of alginate complex shaped structures that closely mimic biological organs or tissues. Alginates can be effectively manufactured into porous three-dimensional networks for tissue engineering applications. However, the structure, mechanical properties, and shape fidelity of 3D-printed alginate hydrogels used for preparing tissue-engineered scaffolds is difficult to control. In this work, the use of alginate/gelatin hydrogels reinforced with TiO2 and β-tricalcium phosphate was studied to tailor the mechanical properties of 3D-printed hydrogels. The hydrogels reinforced with TiO2 and β-TCP showed enhanced mechanical properties up to 20 MPa of elastic modulus. Furthermore, the pores of the crosslinked printed structures were measured with an average pore size of 200 μm. Additionally, it was found that as more layers of the design were printed, there was an increase of the line width of the bottom layers due to its viscous deformation. Shrinkage of the design when the hydrogel is crosslinked and freeze dried was also measured and found to be up to 27% from the printed design. Overall, the proposed approach enabled fabrication of 3D-printed alginate scaffolds with adequate physical properties for tissue engineering applications.

Determination of Local Mechanical Properties of Si3N4 Based Foams

2014 ◽  
Vol 606 ◽  
pp. 213-216 ◽  
Author(s):  
Zuzana Vilčeková ◽  
Monika Kašiarová ◽  
Magdaléna Domanická ◽  
Miroslav Hnatko ◽  
Pavol Šajgalík
Keyword(s):  
Mechanical Properties ◽  
Silicon Nitride ◽  
Resonant Frequency ◽  
Volume Fraction ◽  
Average Pore Size ◽  
Polyurethane Foams ◽  
Average Pore ◽  
Replication Method ◽  
Highly Porous

Local mechanical properties, particularly the hardness and Youngs modulus of highly porous silicon nitride based foams were studied in this work. Silicon nitride foams were prepared using polyurethane foam replication method to obtain appropriate cellular structure suitable for bio-application. Two types of the polyurethane foams were used (with average pore size 0.48 mm and 0.62 mm). Some of these samples were prepared by single or multiple infiltrations. The effects of structures, temperature of calcination, volume fraction of Si3N4 powder and number of the infiltrations on the local mechanical properties were investigated. The Youngs modulus of studied samples range from 12 to 46 GPa at the macroscopic scale measured by resonant frequency technique and from 10 to 28 GPa at the microscopic scale measured by instrumented indentation. Results showed increase of the hardness and Youngs modulus with increasing of the calcination temperature, with increasing of the number of infiltrations and also with increasing of volume fraction of Si3N4 powder in suspension. The results obtained from nanoindentation carry out lower values in comparison with the values measured by resonant frequency technique.

Properties of Hydrophilic Chitosan/Polysulfone Nanofibrous Filtration Membrane

2014 ◽  
Vol 9 (1) ◽  
pp. 155892501400900 ◽  
Author(s):  
Leigen Liu ◽  
Zhijuan Pan
Keyword(s):  
Mechanical Properties ◽  
Pore Size ◽  
Average Pore Size ◽  
High Surface ◽  
Chitosan Solution ◽  
Water Filtration ◽  
Average Pore ◽  
Filtration Membrane ◽  
Crosslinked Chitosan ◽  
Nanofibrous Membranes

Electrospun nanofibrous membranes are useful water filtration materials due to their high interconnected porosity and tunable pore sizes, which cause very high permeability and selectivity. However, poor mechanical properties and easy fouling due to their extremely high surface area limit their applications. Therefore, it is desirable to enhance the mechanical properties and the hydrophilicity of such electrospun nanofibrous membranes. In this paper, electrospun polysulfone (PSF) nanofibrous membranes were treated with plasma. Crosslinked chitosan solution was then employed to pad the membranes. We studied the influence of the chitosan concentration and the volume of glutaraldehyde on the morphology, porosity structure, mechanical properties and hydrophilicity of electrospun polysulfone nanofibrous membranes. The results showed that the average pore size decreased from 4.5 μm to 2.68 μm, the breaking stress increased from 6.01±0.44 MPa to 9.25±0.45 MPa, and the water contact angle decreased from 130.8° to 0° in 30 s when chitosan was applied to the membranes. These changes occurred by padding due to the crosslinked chitosan solution. The results indicate that a significant improvement occurred in the mechanical properties; the highly hydrophobic PSF membrane was changed to a superhydrophilic one and the pore size was reduced. These results encouraged us to propose this material as a water filtration membrane with longer life span, lower fouling and higher rejection efficiency.

Determination of the Permeability of Carbon Aerogels by Gas Flow Measurements

1992 ◽  
Vol 270 ◽  
Author(s):  
F-M. Kong ◽  
S.S. Hulsey ◽  
C.T. Alviso ◽  
R.W. Pekala
Keyword(s):  
Pore Size ◽  
Gas Flow ◽  
Cell Structure ◽  
Average Pore Size ◽  
High Surface ◽  
High Surface Area ◽  
Carbon Aerogels ◽  
Average Pore ◽  
Thin Specimen ◽  
Flow Measurements

ABSTRACTCarbon aerogels are synthesized via the polycondensation of resorcinol and formaldehyde, followed by supercritical drying and pyrolysis at 1050 °C in nitrogen. Because of their interconnected porosity, ultrafine cell structure and high surface area, carbon aerogels have many potential applications, such as in supercapacitors, battery electrodes, catalyst supports, and gas filters. The performance of carbon aerogels in the latter two applications depends on the permeability or gas flow conductance in these materials. By measuring the pressure differential across a thin specimen and the nitrogen gas flow rate in the viscous regime, we calculated the permeability of carbon aerogels from equations based upon Darcy's law. Our measurements show that carbon aerogels have apparent permeabilities on the order of 10−12 to 10−10 cm2 for densities ranging from 0.44 to 0.05 g/cm3. Like their mechanical properties, the permeability of carbon aerogels follows a power law relationship with density and average pore size. Such findings help us to estimate the average pore sizes of carbon aerogels once their densities are known. This paper reveals the relationships among permeability, pore size and density in carbon aerogels.

Development and Characterization of SS316L Foam Prepared by Powder Metallurgy Route

2014 ◽  
Vol 534 ◽  
pp. 31-37 ◽  
Author(s):  
Fazimah Mat Noor ◽  
Khairur Rijal Jamaluddin ◽  
Sufizar Ahmad ◽  
Rosdi Ibrahim ◽  
Noor Idayu Mad Rosip
Keyword(s):  
Powder Metallurgy ◽  
Pore Size ◽  
Bone Cells ◽  
Cell Structure ◽  
Average Pore Size ◽  
Polyurethane Foams ◽  
Vacuum Furnace ◽  
Average Pore ◽  
Open Cell ◽  
Replication Method

Open cell foams, made on the basis of polyurethane foams replication method are well known and had been widely used since decades. The advantage of the network-like metal foams is it exhibits a natural bone-like structure which enables ingrowth of bone cells and blood vessels. The aim of the present study is to develop SS316L foam with an open cell structure by using powder metallurgy routes via foam replication method. The SS316L slurry was produced by mixing SS316L powder with Polyethylene Glycol (PEG), Methylcellulose (CMC) and distilled water. The composition of the SS316L powder in the slurry was varied from 40 to 60 wt. %. Then, polymeric foam template was impregnated in SS316L slurry and dried at room temperature. Sintering was carried out in a high temperature vacuum furnace at 1300°C. The microstructure of the SS316L foam produced was observed by Scanning Electron Microscope (SEM) and the elemental analysis was carried by Energy Dispersive X-ray (EDX). It was found that pore size are within 200-400μm and the average pore size is 293μ. The detected elements in the SS316L foam were C, Al, Ca, O, Cr, Fe, Mo, Ni and Si.

Structural Characteristics and Mechanical Properties of Biomedical Porous Ti-10Mo Alloy Fabricated by Selective Laser Sintering

2012 ◽  
Vol 520 ◽  
pp. 234-241
Author(s):  
Fang Xia Xie ◽  
Xin Lu ◽  
Xin Bo He ◽  
Xuan Hui Qu
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Sintering Temperature ◽  
Structural Characteristics ◽  
Average Pore Size ◽  
Selective Laser Sintering ◽  
Compressive Yield Strength ◽  
Average Pore ◽  
Porous Ti ◽  
Interconnected Pores

Ti-Mo alloy is one of the most prospective metallic biomaterials for implant application because of its low elastic modulus, high corrosion resistance and tissue compatibility. A complex-shaped porous Ti-10Mo alloy from a mixture of elemental metal powders and polymer binders was processed by selective laser sintering forming, followed by thermal debinding and sintering in vacuum. The effects of processing parameters on structural characteristics and mechanical properties were studied. The results indicate that the pore characteristic parameters, matrix microstructure and mechanical properties strongly depend on the sintering temperature. Specimens sintered at 1100 °C exhibit a higher porosity of 52.41%, and possess many three-dimensionally interconnected pores with an average size of 200 μm, and the matrix is dominated by α and β phases, and meanwhile the alloy exhibits a compressive yield strength of 95.59 MPa and an elastic modulus of 4.89 GPa at room temperature. With the rise in sintering temperature, both the porosity and the average pore size of specimens gradually decrease, and the interconnected pores tend to be closed. Specimens sintered at 1400 °C are characterized by a porosity of 26.32% and an average pore size of 60 μm with a compressive yield strength of 440 MPa and an elastic modulus of 35.26 GPa.

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