The Effect of Sintering Temperature on the Microstructural and Mechanical Characteristics of Hydroxyapatite Macroporous Scaffolds Prepared via Freeze-Casting

2012 ◽  
Vol 529-530 ◽  
pp. 133-137 ◽  
Author(s):  
Ali Zamanian ◽  
Sajad Farhangdoust ◽  
Mana Yasaei ◽  
Mina Khorami ◽  
Mohamad Abbasabadi
Keyword(s):  
Compressive Strength ◽  
Mechanical Characteristics ◽  
Sintering Temperature ◽  
Total Porosity ◽  
Sintered Sample ◽  
Dendritic Branch ◽  
Injured Tissue ◽  
Freeze Dried ◽  
Different Temperatures ◽  
Bone Repairing

The most important characteristic of biomaterial as bone-repairing material, in addition to biocompatibility and appropriate porosity, is providing mechanical strength complying with injured tissue. In the present work, slurry with 15 vol% HA prepared from calcinated hydroxyapatite. The prepared slurry freeze casted unidirectionally with the cooling rate of 8°C/min from the ambient temperature. Then, green bodies freeze-dried for 72h following with sintering at different temperatures of 1250-1350°C with intervals of 25°C. The results showed that lamella space and porosity decreases with temperature while compressive strength and shrinkage goes up. Total porosity has a range of 75-83% while has a compressive strength of ~2-8 MPa. The sintered sample at 1350°C, with 75% porosity, which has a ~ 8 MPa compressive strength, chose to be the optimum. Also, some dendritic branch like structure and bridges can be seen on the internal walls of lamellae which can improve mechanical properties. These features may improve adhesion and growth of osseous cells.

Evaluating Initial Content of the Slurry and Cooling Rate on the Microstructural and Mechanical Characteristics of Freeze Casted Hydroxyapatite Macroporous Scaffolds

2012 ◽  
Vol 529-530 ◽  
pp. 147-152 ◽  
Author(s):  
Sajad Farhangdoust ◽  
Sayed Mahmood Rabiee ◽  
Ali Zamanian ◽  
Mana Yasaei ◽  
Mina Khorami ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Cooling Rate ◽  
Mechanical Characteristics ◽  
Proximal Tibia ◽  
Total Porosity ◽  
A Value ◽  
Physical Chemical ◽  
Freeze Dried ◽  
Biological Criteria ◽  
Initial Content

Scaffolds have to meet exacting physical, chemical, and biological criteria to function successfully, and those criteria vary with the type of tissue being repaired. In the present work, slurry with different initial content of 7.5-22.5 vol% HA prepared from calcinated hydroxyapatite. The prepared slurries freeze casted unidirectionally with the different cooling rate of 2-14°C/min with intervals of 3°C/min from the ambient temperature. Then, green bodies freeze-dried for 72h following with sintering at temperatures of 1350°C. The results showed that compressive strength goes up with cooling rate and initial content. Total porosity has a range of 66-88% while has a compressive strength of ~0.4-18 MPa. Porosity size has a value of 20-200 μm by initial content and cooling rate. Based on strength and porosity, the specimen with initial content and cooling rate of 15 vol% and 5°C/min, respectively, chose to be the optimum. This specimen has a compressive strength and porosity size of 5.26 MPa and 88 μm, respectively. The compressive strength value of the mentioned lamellar HA scaffolds was in the range of the values reported for human proximal tibia.

Experimental Study on the Compressive Strength and AE Characteristics of High-temperature Treated and LN2 Cooled Sandstone

2021 ◽  
Author(s):  
Rui Ding ◽  
Qiang Sun ◽  
Hailiang Jia ◽  
Liyun Tang ◽  
Delu Li
Keyword(s):  
Compressive Strength ◽  
Temperature Difference ◽  
Room Temperature ◽  
Shear Failure ◽  
Total Porosity ◽  
High Porosity ◽  
Quenching Temperature ◽  
Red Sandstone ◽  
Different Temperatures ◽  
Development And Utilization

Abstract Liquid nitrogen (LN2) fracturing is beneficial to the development and utilization of geothermal energy. In this paper, the red sandstone was heated from room temperature to different temperatures (25°C-800°C) and then cooled with LN2. After attaining the room temperature, NMR, uniaxial compression, and acoustic emission (AE) tests were conducted, and results were compared for different samples. The results showed that with the increase in quenching temperature difference, the volume of micropores decreased gradually, while the volume of fine pores, mesopores, macropores and total porosity increased, resulting in the reduction of the compressive strength. Higher quenching temperature difference also reduced the sample’s total time to fail, and the failure mode was transformed from single inclined shear failure to conical failure. This is because the thermal stress (caused by the rapid cooling of LN2) expanded the original cracks of the sandstone, leading to high porosity and low compressive strength of the heat-treated and quenched samples.

scholarly journals The Influence of Sewage Sludge Content and Sintering Temperature on Selected Properties of Lightweight Expanded Clay Aggregate

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3363
Author(s):  
Jolanta Latosińska ◽  
Maria Żygadło ◽  
Przemysław Czapik
Keyword(s):  
Sewage Sludge ◽  
Water Absorption ◽  
Apparent Density ◽  
Environmental Sustainability ◽  
Sintering Temperature ◽  
Total Porosity ◽  
Raw Material ◽  
Closed Porosity ◽  
Specific Density ◽  
Sustainability Principles

Wastewater treatment processes produce sewage sludge (SS), which, in line with environmental sustainability principles, can be a valuable source of matter in the production of lightweight expanded clay aggregate (LECA). The literature on the influence of SS content and sintering temperature on the properties of LECA is scarce. This paper aims to statistically evaluate the effects of SS content and sintering temperature on LECA physical properties. Total porosity, pore volume, and apparent density were determined with the use of a density analyzer. A helium pycnometer was utilized to determine the specific density. Closed porosity was calculated. The test results demonstrated a statistically significant influence of the SS content on the specific density and water absorption of LECA. The sintering temperature had a significant effect on the specific density, apparent density, total porosity, closed porosity, total volume of pores, and water absorption. It was proved that a broad range of the SS content is admissible in the raw material mass for the production of LECA.

scholarly journals Carbonization Durability of Two Generations of Recycled Coarse Aggregate Concrete with Effect of Chloride Ion Corrosion

2020 ◽  
Vol 12 (24) ◽  
pp. 10544
Author(s):  
Chunhong Chen ◽  
Ronggui Liu ◽  
Pinghua Zhu ◽  
Hui Liu ◽  
Xinjie Wang
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Chloride Ion ◽  
Total Porosity ◽  
Recycled Concrete ◽  
Carbonation Depth ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Carbonation Resistance ◽  
Two Generations

Carbonation durability is an important subject for recycled coarse aggregate concrete (RAC) applied to structural concrete. Extensive studies were carried out on the carbonation resistance of RAC under general environmental conditions, but limited researches investigated carbonation resistance when exposed to chloride ion corrosion, which is an essential aspect for reinforced concrete materials to be adopted in real-world applications. This paper presents a study on the carbonation durability of two generations of 100% RAC with the effect of chloride ion corrosion. The quality evolution of recycled concrete coarse aggregate (RCA) with the increasing recycling cycles was analyzed, and carbonation depth, compressive strength and the porosity of RAC were measured before and after chloride ion corrosion. The results show that the effect of chloride ion corrosion negatively affected the carbonation resistance of RAC, and the negative effect was more severe with the increasing recycling cycles of RCA. Chloride ion corrosion led to a decrease in compressive strength, while an increase in carbonation depth and the porosity of RAC. The equation of concrete total porosity and carbonation depth was established, which could effectively judge the deterioration of carbonation resistance of RAC.

scholarly journals The effect of drying temperature on the properties of gelatin from carps (Cyprinus carpio) skin

2019 ◽  
Vol 37 (No. 4) ◽  
pp. 246-251 ◽  
Author(s):  
Joanna Tkaczewska ◽  
Maciej Wielgosz ◽  
Piotr Kulawik ◽  
Marzena Zajac
Keyword(s):  
Cyprinus Carpio ◽  
Freeze Drying ◽  
Treatment Method ◽  
Thermal Hydrolysis ◽  
Gel Properties ◽  
Drying Temperature ◽  
Freeze Dried ◽  
Different Temperatures ◽  
Pre Treatment ◽  
Hydrolysis Of

The influence of drying temperature on the characteristics and gel properties of gelatine from Cyprinus carpio L. skin was studied. Gelatine was extracted from the carp skin using NaOH and ethanol pre-treatment method, extracted in water in 45°C and then dried in 4 different temperatures: 50, 70, 80°C and freeze-dried. The  electrophoresis and functional properties of gelatines were investigated. Freeze drying allowed to obtain a high gelling force, and all other methods did not give satisfactory results. The proteins in gelatines dried at higher temperatures separated by electrophoresis gave severely blurred bands. It may be explained by thermal hydrolysis of collagen fibrils. Freeze drying is the only effective method for drying this product, which can be used in industry.

Effect of Reinforcement and Tribological Behaviour of AA 7068 Hybrid Composites Manufactured through Powder Metallurgy Techniques

2017 ◽  
Vol 867 ◽  
pp. 19-28 ◽  
Author(s):  
J. Lakshmipathy ◽  
Subburaj Rajesh Kannan ◽  
K. Manisekar ◽  
S. Vinoth Kumar
Keyword(s):  
Sintering Temperature ◽  
Hybrid Composites ◽  
High Strength ◽  
Phase Changes ◽  
Wear Loss ◽  
X Ray Diffraction ◽  
Tribological Behaviour ◽  
Different Temperatures ◽  
Pin On Disc ◽  
Sliding Distance

In this article, an attempt was made to study the mechanical behaviour of AA7068 - 6 vol. % of MoS2 - X vol. % of WC (X = 0, 5, 10 and 15) hybrid aluminium composites produced by blend–press–sinter methodology. Compacted Powders (700MPa) were sintered at different temperatures (450 0c, 500 0c and 550 0c ) in order to find the influence of sintering temperature on mechanical properties and tribological behavior of AA7068 hybrid composites.The sintered samples have been characterized by x-ray diffraction (XRD) method for identification of phases and also to investigate the phase changes. The change in density, hardness and porosity values of composites were reported. The composite with 15 vol. % of tungsten carbide and 6 vol. % of MoS2 showed the highest hardness and density at the sintering temperature range of 550 0c. Pin-on-disc type apparatus was used for determining the wear loss occurring at different conditions. The hybridization of the two reinforcements enhanced the wear resistance of the composites, especially under high applied load, sliding distance and sliding speeds. Due to this, the hybrid aluminium composites can be considered as an outstanding material where high strength and wear-resistant components are of major importance, predominantly in the aerospace and automotive engineering sectors. The morphology of the wear debris and the worn out surfaces were analyzed to understand the wear mechanisms.

scholarly journals Amorphous fiber based on the Fe-B-C molten system for bulk reinforcement of concrete

2018 ◽  
Vol 245 ◽  
pp. 03019 ◽  
Author(s):  
Artemiy Cherkashin ◽  
Yasmin Begich ◽  
Polina Sherstobitova ◽  
Oleg Tolochko
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Mechanical Characteristics ◽  
Test Material ◽  
Comparative Tests ◽  
Physical And Mechanical Characteristics

The article deals with the use of amorphous fiber of the Fe-B-C system, which was obtained by spinning the melt. Comparative tests of the samples made on the basis of the test material on the compressive strength and tensile strength of the traditional destructive method were made. The conductivity of the samples was also tested. Physical and mechanical characteristics of the material are obtained.

CHARACTERIZATION OF HYDROXYAPATITE/TI6AL4V COMPOSITE POWDER UNDER VARIOUS SINTERING TEMPERATURE

2015 ◽  
Vol 75 (7) ◽  
Author(s):  
Amir Arifin ◽  
Abu Bakar Sulong ◽  
Norhamidi Muhamad ◽  
Junaidi Syarif
Keyword(s):  
Mechanical Properties ◽  
Composite Powder ◽  
Sintering Temperature ◽  
Physical And Mechanical Properties ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Different Temperatures ◽  
Two Phases ◽  
Work Interaction

Hydroxyapatite (HA) has been widely used in biomedical applications due to its excellent biocompatibility. However, Hydroxyapatite possesses poor mechanical properties and only tolerate limited loads for implants. Titanium is well-known materials applied in implant that has advantage in mechanical properties but poor in biocompatibility. The combination of the Titanium alloy and HA is expected to produce bio-implants with good in term of mechanical properties and biocompatabilty. In this work, interaction and mechanical properties of HA/Ti6Al4V was analyzed. The physical and mechanical properties of HA/Ti6Al4V composite powder obtained from compaction (powder metallurgy) of 60 wt.% Ti6Al4V and 40 wt.% HA and sintering at different temperatures in air were investigated in this study. Interactions of the mixed powders were investigated using X-ray diffraction. The hardness and density of the HA/Ti6Al4V composites were also measured. Based on the results of XRD analysis, the oxidation of Ti began at 700 °C. At 1000 °C, two phases were formed (i.e., TiO2 and CaTiO3). The results showed that the hardness HA/Ti6Al4V composites increased by 221.6% with increasing sintering temperature from 700oC to 1000oC. In contrast, the density of the composites decreased by 1.9% with increasing sintering temperature. 

Sintering Temperature Effect on Hardness of Self-Synthetisized Porcelain Made from Natural Sumatran Sand without Kaolin

2018 ◽  
Vol 782 ◽  
pp. 227-232
Author(s):  
Sianny Surya Putri Kurnia ◽  
Dede Taufik ◽  
Veni Takarini ◽  
Zulia Hasratiningsih
Keyword(s):  
Temperature Effect ◽  
Potassium Salt ◽  
Sintering Temperature ◽  
The Self ◽  
The Other ◽  
P Value ◽  
Natural Sand ◽  
Average Hardness ◽  
Different Temperatures ◽  
Statistic Result

Dental porcelain is one of the indirect restoration material with excellent aesthetic properties,on the other hand porcelain hardness frequently causing excessive wear of antagonist teeth. This study aiming to evaluate the effect of sintering temperature on the self-synthesized porcelain hardness. In this experiment, 25 porcelain samples were synthesized using Sumatran sand from Pangaribuan and Belitung regions, with the composition of 65 wt% Pangaribuan feldspar, 25 wt% Belitung silica and 10 wt% potassium salt. The samples were sintered in five different temperatures, which were 1110°C (A), 1120°C (B), 1130°C (C), 1140°C (D), and 1150°C (E). These samples were then invested on 5cm diameter resin each. The hardness was tested using Zwick Roell ZHμ Micro Vickers with 900 gram load for 15 seconds in 5 different indented areas for each sample. The result shows average hardness of 435.8 VHN (A), 461.0 VHN (B), 472.0 VHN (C), 487.6 VHN (D), and 528.7 VHN (E), which were increasing as the sintering temperature increased. Statistic result shows that sintering temperature significantly affected the hardness value of the porcelain (p value < 0.05). In conclusion sintering temperature affects the hardness of self-synthesized porcelain made from Sumatran natural sand without kaolin, although the average hardness of self-synthesized porcelain is still higher than average hardness of teeth enamel.

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