scholarly journals Studies on Characterization of Bovine Hydroxyapatite/CaTiO3Biocomposites

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Suat Ozturk ◽  
Mehmet Yetmez

Sintering effects and mechanical properties of bovine hydroxyapatite/CaTiO3composites are investigated for different CaTiO3ratios. Results indicate that densities of the biocomposites increase while total porosities of those decrease with increasing sintering temperature. Moreover, modulus of elasticity and microhardness increase with increasing sintering temperature. However, values of both toughness and fracture toughness of the biocomposites generally rise with increasing sintering temperature except for 1300°C.

2012 ◽  
Vol 31 (6) ◽  
pp. 749-753 ◽  
Author(s):  
Melis Ozmen ◽  
Ipek Akin ◽  
Muzeyyen Marsoglu

AbstractHydroxyapatite (HA) ceramics are used extensively in different medical applications, such as biomaterial for repair or replacement of bone tissues since it resembles mineral component of bone and teeth. However, HA exhibits low fracture toughness due to its lack of strength and brittleness, thereby providing an obstacle to its application in implants that must withstand to high loads. In this study, HA was synthesized from human teeth by using a single calcinations method. Hydroxyapatite powders were mixed with different amounts of zirconia. The composites were sintered at different temperatures and characterized in terms of mechanical properties and the optimum sintering temperature was determined for good mechanical properties.


Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.


Author(s):  
K.L. More ◽  
R.A. Lowden

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.


2012 ◽  
Vol 476-478 ◽  
pp. 1031-1035
Author(s):  
Wei Min Liu ◽  
Xing Ai ◽  
Jun Zhao ◽  
Yong Hui Zhou

Al2O3-TiC-ZrO2ceramic composites (ATZ) were fabricated by hot-pressed sintering. The phases and microstructure of the composites were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The relative density and mechanical properties (flexural strength, fracture toughness and Vicker’s hardness) of the composites were tested. The results show that the microstructure of the composites was the gray core-white rim. With the increase of sintering temperature, the relative density and mechanical properties of the composites increased first and then decreased. The composite sintered at 1705°C has the highest synthetical properties, and its relative density, flexural strength, fracture toughness and Vickers hardness are 98.3%,970MPa,6.0 MPa•m1/2and 20.5GPa, respectively.


2013 ◽  
Vol 589-590 ◽  
pp. 590-593 ◽  
Author(s):  
Min Wang ◽  
Jun Zhao

In order to investigate the effects of TiN content on Al2O3/TiN ceramic material (ATN), the ATN ceramic materials were prepared of TiN content in 30%, 40%, 50%, 60% in the condition of hot press sintering. The sintering temperature is 1700°C, the sintering press is 32MPa, and the holding time are 5min, 10min, 15min. The effects of TiN content on mechanical properties and microstructure of ATN ceramic materials were investigated by analyzing the bending strength, hardness, fracture toughness. The results show that ATN50 has the best mechanical property, its bending strength is 659.41MPa, vickers hardness is 13.79GPa, fracture toughness is 7.06MPa·m1/2. It is indicated that the TiN content has important effect on microstructure and mechanical properties of ATN ceramic materials.


2015 ◽  
Vol 75 (7) ◽  
Author(s):  
Amir Arifin ◽  
Abu Bakar Sulong ◽  
Norhamidi Muhamad ◽  
Junaidi Syarif

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. 


2021 ◽  
Vol 1016 ◽  
pp. 1770-1777
Author(s):  
Liu Zhu ◽  
Jin Fang Wang ◽  
Zhi Biao Tu ◽  
Na Xue ◽  
Wei Wei Li

The WC composite powder was synthesized by a new specific chemical activation technique. A large number of lattice defects such as surface humps, dislocations and stacking fault exist in the surface of the WC powder after chemical activation technique. By using such activated WC powder, the binderless WC cemented carbide with high density (15.54 g/cm3), super hardness (average 26.29 GPa) and excellent fracture toughness (8.9 MPa.m1/2) can be fabricated by SPS at 1700 °C and 50 MPa pressure. The improvement in density, hardness and fracture toughness are respectively 4.5%, 15.3% and 17.1% compared to when using the original WC powder. This improvement is because microscopic defects on the surface of the WC powder can greatly improve surface free energy of the powder, which improves the sintering activity and reduces the sintering temperature of the WC powder.


2002 ◽  
Vol 740 ◽  
Author(s):  
Mats Carlsson ◽  
Mats Johnsson ◽  
Annika Pohl

ABSTRACTCeramic composites containing 2 and 5vol. % of nanosized commercially available TiN and SiC particles in alumina were prepared via a water based slurry processing route followed by spark plasma sintering (SPS) at 75 MPa in the temperature range 1200–1600°C. Some of the samples could be fully densified by use of SPS already after five minutes at 1200°C and 75 MPa. The aim was to control the alumina grain growth and thus obtain different nano-structure types. The microstructures have been correlated to some mechanical properties; e.g. hardness and fracture toughness.


2005 ◽  
Vol 287 ◽  
pp. 335-339 ◽  
Author(s):  
Kyeong Sik Cho ◽  
Kwang Soon Lee

Rapid densification of the SiC-10, 20, 30, 40wt% TiC powder with Al, B and C additives was carried out by spark plasma sintering (SPS). In the present SPS process, the heating rate and applied pressure were kept at 100°C/min and at 40 MPa, while the sintering temperature varied from 1600-1800°C in an argon atmosphere. The full density of SiC-TiC composites was achieved at a temperature above 1800°C by spark plasma sintering. The 3C phase of SiC in the composites was transformed to 6H and 4H by increasing the process temperature and the TiC content. By tailoring the microstructure of the spark-plasma-sintered SiC-TiC composites, their toughness could be maintained without a notable reduction in strength. The strength of 720 MPa and the fracture toughness of 6.3 MPa·m1/2 were obtained in the SiC-40wt% TiC composite prepared at 1800°C for 20 min.


Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2046 ◽  
Author(s):  
Yi Jing ◽  
Hongbing Yuan ◽  
Zisheng Lian

ZrB2–HfC ceramics have been fabricated using the liquid phase sintering technique at a sintering temperature as low as 1750 °C through the addition of Ni. The effects of HfC addition on the microstructure and mechanical properties of ZrB2–based ceramics have been investigated. These ceramics were composed of ZrB2, HfC, Ni, and a small amount of possible (Zr, Hf)B2 solid solution. Small HfC grains were distributed among ZrB2 grain boundaries. These small grains could improve the density of ZrB2–based ceramics and play a pinning role. With HfC content increasing from 10 wt % to 30 wt %, more HfC grains were distributed among ZrB2 grain boundaries, leading to weaker interface bonding among HfC grains; the relative density and Vickers hardness increased, and flexural strength and fracture toughness decreased. The weak interface bonding for 20 and 30 wt % HfC contents was the main cause of the decrease in both flexural strength and fracture toughness.


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