scholarly journals Nanocrystalline Hydroxyapatite Ceramics Prepared by Hydrolysis in Polyol Medium, Microstructure and Mechanical Properties after Spark Plasma Sintering

2013 ◽  
Vol 6 (3) ◽  
pp. 1085-1092 ◽  
Author(s):  
Abderrahmen Mechay ◽  
Noureddine Jouini ◽  
Fréderic Schoenstein

This Letter describes a new approach for the synthesis of hydroxyapatite (HA) nanoparticles by polyol process has been successfully conducted by spark plasma sintering process, resulting in a dense hydroxyapatite compacts. Besides, the sintering behaviour of hydroxyapatite powders at different temperatures ranging from 800°C to 950°C at 50 MPa was studied. The microstructure, Vickers microhardness, fracture toughness and density are described. The suitable sintering condition under the pressure of 50 MPa is 900°C for 5 min. A maximum value of the density was reached at around 900°C, and then decreased with further increase in the temperature due to the decomposition of hydroxyapatite into β-tricalcium phosphates.

2011 ◽  
Vol 49 (01) ◽  
pp. 40-45 ◽  
Author(s):  
Hyun-Kuk Park ◽  
Seung-Min Lee ◽  
Hee-Jun Youn ◽  
Ki-Sang Bang ◽  
Ik-Hyun Oh

Author(s):  
B Stalin ◽  
M Ravichandran ◽  
M Balasubramanian ◽  
C Anand Chairman ◽  
D Pritima ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2993
Author(s):  
Dong-won Shin ◽  
Peyala Dharmaiah ◽  
Jun-Woo Song ◽  
Soon-Jik Hong

In this work, Bi0.5Sb1.5Te3 materials were produced by an economically viable and time efficient water atomization process. The powder samples were heat treated at different temperatures (673 K, 723 K, 743 K, 773 K, 803 K, and 823 K) followed by spark plasma sintering (SPS). It was found that the Te evaporated slightly at 723 K and 743 K and became dominated at 773 K, 803 K, and 823 K, which severely influences the thermoelectric properties. The electrical conductivity was significantly improved for over 803 K heat treated samples due to the remarkable improvement in hole concentration. The power factor values for the 803 K and 823 K samples were significantly larger at T > 350 K compared to other samples. Consequently, the peak ZT of 0.92 at 350 K was obtained for the 803 K sample, which could be useful in commercial thermoelectric power generation.


2019 ◽  
Vol 18 ◽  
pp. 3791-3797
Author(s):  
Okoro Avwerosuoghene Moses ◽  
Cosssa Themba Edmond ◽  
Thaba Thapelo Precious ◽  
Lephuthing Senzeni Sipho ◽  
Oke Samuel Ranti ◽  
...  

2015 ◽  
Vol 13 ◽  
pp. 83-90 ◽  
Author(s):  
Cristiana Diana Cristea ◽  
Magdalena Lungu ◽  
Alexander M. Balagurov ◽  
Virgil Marinescu ◽  
Otilia Culicov ◽  
...  

The addition of Cu to near equiatomic NiTi shape memory alloys (SMAs) can provide some modifications of their shape memory properties by affecting their transformation behavior. The same effect was obtained in the case of Ni3Ti2 and Ni4Ti3 precipitates presence in the microstructure of NiTi. Also the substitution of Cu to NiTi alloys increases the hardness of the materials. This paper presents the microstructural and mechanical investigations of NiTi and NiTiCu alloys obtained by spark plasma sintering (SPS) process that represents a great potential for researchers as a new process for the fabrication of intermetallic compounds.


2008 ◽  
Vol 49 (12) ◽  
pp. 2899-2906 ◽  
Author(s):  
Salvatore Grasso ◽  
Yoshio Sakka ◽  
Giovanni Maizza

2016 ◽  
Vol 881 ◽  
pp. 307-312
Author(s):  
Luis Antonio C. Ybarra ◽  
Afonso Chimanski ◽  
Sergio Gama ◽  
Ricardo A.G. da Silva ◽  
Izabel Fernanda Machado ◽  
...  

Tungsten carbide (WC) based composites are usually produced with cobalt, but this binder has the inconvenience of shortage, unstable price and potential carcinogenicity. The objective of this study was to develop WC composite with intermetallic Fe3Al matrix. Powders of WC, iron and aluminum, with composition WC-10 wt% Fe3Al, and 0.5 wt% zinc stearate were milled in a vibration mill for 6 h and sintered in a SPS (spark plasma sintering) furnace at 1150 °C for 8 min under pressure of 30 MPa. Measured density and microstructure analysis showed that the composite had significant densification during the (low-temperature, short time) sintering, and X-ray diffraction analysis showed the formation of intermetallic Fe3Al. Analysis by Vickers indentation resulted in hardness of 11.2 GPa and fracture toughness of 24.6 MPa.m1/2, showing the feasibility of producing dense WC-Fe3Al composite with high mechanical properties using the SPS technique.


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