The preparation and characterization of porous alumina ceramics using an eco‐friendly pore‐forming agent

2018 ◽  
Vol 16 (2) ◽  
pp. 820-831 ◽  
Author(s):  
Julian Alzukaimi ◽  
Rafi Jabrah
2017 ◽  
Vol 125 (5) ◽  
pp. 402-412 ◽  
Author(s):  
Mohammed Sabah ALI ◽  
M. A. Azmah HANIM ◽  
S. M. TAHIR ◽  
C. N. A. JAAFAR ◽  
M. NORKHAIRUNNISA ◽  
...  

Cerâmica ◽  
2020 ◽  
Vol 66 (378) ◽  
pp. 208-220
Author(s):  
J. Alzukaimi ◽  
R. Jabrah

Abstract Porous alumina ceramics were prepared through the space holder technique, using ground sunflower seed shells as a fugitive material and uniaxial pressing for forming the green ceramics. Influences of the sunflower seed shell content on the shrinkage of the green bodies and porosity of sintered products were evaluated. The prepared ceramics were characterized for mechanical properties using the Brazilian disk test, and the porosity effect on the measured strength was determined. The microstructure was characterized by SEM. The sunflower seed shell content was varied from 0 to 60 wt%. Porosities within 29.9-71.0 vol% were achieved, and the strength of the obtained alumina ceramics decreased accordingly from 59.7 to 4.0 MPa. Additional samples, prepared with different compaction pressure, were characterized for electrical properties and showed high electrical insulation capability, which increased with porosity. Mechanical and electrical data were discussed based on theoretical models, namely the Gibson-Ashby model and/or the minimum solid area model.


Cerâmica ◽  
2019 ◽  
Vol 65 (suppl 1) ◽  
pp. 70-74 ◽  
Author(s):  
G. C. Ribeiro ◽  
B. A. Fortes ◽  
L. da Silva ◽  
J. A. Castro ◽  
S. Ribeiro

Cerâmica ◽  
2015 ◽  
Vol 61 (358) ◽  
pp. 160-167 ◽  
Author(s):  
A. W. Huang ◽  
C. Santos ◽  
R. O. Magnago ◽  
R. F. F. Silva ◽  
K. Strecker ◽  
...  

<p>Alumina-based ceramics, Al<sub>2</sub>O<sub>3</sub>, exhibit a combination of properties which favor its use as biomaterial, specifically as structural dental prosthesis. Its most important properties as biomaterial are its elevated hardness, chemical stability and biocompatibility. Usually, Al<sub>2</sub>O<sub>3</sub> is processed by solid-state sintering at a temperature of about 1600 <sup>o</sup>C, but it is very difficult to eliminate the porosity due to its diffusional characteristics. The objective of this work was the development and characterization of sintered Al<sub>2</sub>O<sub>3</sub> ceramics, densified with a transient liquid phase formed by a bioactive 3CaO.P<sub>2</sub>O<sub>5</sub>-SiO<sub>2</sub>-MgO glass. Powder mixtures of 90 wt.% Al<sub>2</sub>O<sub>3</sub> and 10 wt.% bioglass were milled, compacted and sintered at 1200 <sup>o</sup>C to 1450 <sup>o</sup>C. Comparatively, monolithic Al<sub>2</sub>O<sub>3</sub> samples were sintered at 1600 <sup>o</sup>C/120 min. The sintered specimens were characterized by relative density, crystalline phases, microstructure and mechanical properties. The results indicate that the specimen sintered at 1450 <sup>o</sup>C/120 min present the best properties. Under this sintering condition, a relative density of 95% was reached, besides hardness higher than 9 GPa and fracture toughness of 6.2 MPa.m<sup>1/2</sup>. XRD analysis indicate alumina (αAl<sub>2</sub>O<sub>3</sub>), whitlockite (3CaO.P<sub>2</sub>O<sub>5</sub>) and diopsite [3(Ca,Mg)O.P<sub>2</sub>O<sub>5</sub>], as crystalline phases. Comparatively, monolithic sintered Al<sub>2</sub>O<sub>3</sub> samples presented 92% of relative density with 17.4 GPa and 3.8 MPa.m<sup>1/2</sup> of hardness and fracture toughness respectively.</p>


2004 ◽  
Vol 455-456 ◽  
pp. 322-325
Author(s):  
Ren Li Fu ◽  
Yan Bao Li ◽  
Xin Xu ◽  
José Maria F. Ferreira

2006 ◽  
Vol 17 (9) ◽  
pp. 2146-2151 ◽  
Author(s):  
M Kokonou ◽  
A G Nassiopoulou ◽  
K P Giannakopoulos ◽  
A Travlos ◽  
T Stoica ◽  
...  

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