TY - GEN
T1 - A simple and economical device to process Ti cylinders with elongated porosity by freeze-casting techniques
T2 - 4th International Conference on Powder Metallurgy of Titanium, PMTi 2017
AU - Muñoz, Paloma Trueba
AU - Bascón Suárez, Joaquín R.
AU - Beltrán, Ana M.
AU - Rodriguez-Ortiz, José Antonio
AU - Hernández, Yadir Torres
AU - Palacio, Juan José Pavón
AU - Álvarez, Esteban Alonso
AU - Dunand, David C.
N1 - Funding Information:
This project has been supported by the Regional Government of Andalusia (FEDER) through Project P12-TEP-1401 and the Ministry of Economy and Innovation of Spain within project MAT2015-71284-P. The authors also thanks to technician J. Pinto for his collaboration in the characterization works.
PY - 2018
Y1 - 2018
N2 - Nowadays, the development of materials with gradient porosity is an important aim for many applications, especially in the field of bone tissue replacement. This research work shows the design and manufacture of a simple and economical device to process Ti cylinders with elongated and high interconnected porosity by freeze-casting techniques. The influence of the vessel material on the internal lamellar structure of the porous Ti samples is also studied. The device has been validated with: (i) a thermal gradient from -10 °C at the cold surface to 20 °C at the hot surface; and (ii) a cylindrical vessel with 12 mm diameter of alumina or Teflon. These working conditions have allowed maintaining the freezing conditions during the full process (alumina vessel: 30 minutes; Teflon vessel: 3 hours). After the solidification of the Ti aqueous suspension, the ice is sublimated (24 hours at -50 °C and 0.070 mbar). Then, the resulting powder is sintered (1150 °C for 5 h at high vacuum ~ 10-5 mbar), obtaining the porous Ti sample with the final structural strength. Finally, a detailed study of the most relevant porosity features is performed: porosity ratio and interconnectivity degree by Archimedes' method, and size and shape of the pores by image analysis at three different zones along the longitudinal cross section. The results indicate the viability of the device to enhance the directional freezing and thus, the elongated porosity. Teflon vessel present the best results, with an average porosity ratio and porosity size of 39.5 % and 123.3 µm, respectively. This suggests an optimal biomechanical and bifunctional balance of this porous material.
AB - Nowadays, the development of materials with gradient porosity is an important aim for many applications, especially in the field of bone tissue replacement. This research work shows the design and manufacture of a simple and economical device to process Ti cylinders with elongated and high interconnected porosity by freeze-casting techniques. The influence of the vessel material on the internal lamellar structure of the porous Ti samples is also studied. The device has been validated with: (i) a thermal gradient from -10 °C at the cold surface to 20 °C at the hot surface; and (ii) a cylindrical vessel with 12 mm diameter of alumina or Teflon. These working conditions have allowed maintaining the freezing conditions during the full process (alumina vessel: 30 minutes; Teflon vessel: 3 hours). After the solidification of the Ti aqueous suspension, the ice is sublimated (24 hours at -50 °C and 0.070 mbar). Then, the resulting powder is sintered (1150 °C for 5 h at high vacuum ~ 10-5 mbar), obtaining the porous Ti sample with the final structural strength. Finally, a detailed study of the most relevant porosity features is performed: porosity ratio and interconnectivity degree by Archimedes' method, and size and shape of the pores by image analysis at three different zones along the longitudinal cross section. The results indicate the viability of the device to enhance the directional freezing and thus, the elongated porosity. Teflon vessel present the best results, with an average porosity ratio and porosity size of 39.5 % and 123.3 µm, respectively. This suggests an optimal biomechanical and bifunctional balance of this porous material.
KW - Freeze-casting technique
KW - Gradient porosity
KW - Porous titanium
UR - http://www.scopus.com/inward/record.url?scp=85047851674&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85047851674&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/KEM.770.255
DO - 10.4028/www.scientific.net/KEM.770.255
M3 - Conference contribution
AN - SCOPUS:85047851674
SN - 9783035711639
T3 - Key Engineering Materials
SP - 255
EP - 261
BT - Titanium Powder Metallurgy and Additive Manufacturing
A2 - Tang, Huiping
A2 - Chen, Gang
A2 - Qian, Ma
A2 - Liu, Yong
A2 - Cao, Peng
PB - Trans Tech Publications Ltd
Y2 - 8 September 2017 through 10 September 2017
ER -