TY - JOUR
T1 - High precision pulp-based sacrificial molds
T2 - A solution towards mass production of hollow ceramic spheres for deep sea applications
AU - Rastogi, Vibhore Kumar
AU - Sturzenegger, Philip N.
AU - Gonzenbach, Urs T.
AU - Vetterli, Marc
AU - Naikade, Manoj
AU - Kesari, Kavindra Kumar
AU - Ruokolainen, Janne
AU - Kuebler, Jakob
AU - Blugan, Gurdial
N1 - Funding Information:
The authors would like to acknowledge the financial support of the Swiss Commission of Technology and Innovation for funding this work under the project “DeepC” KTI project No. 19260.1 PFIW-IW. Roland Bächtold for helping with the designing of press molds. Dr. Thomas Geiger (Empa, Wood Department) for assisting with the hot pressing machine and Dr. Anja Huch (Empa, Wood Department) for help with contact angle measurements.
Publisher Copyright:
© 2021 Elsevier Ltd and Techna Group S.r.l.
PY - 2022/3/15
Y1 - 2022/3/15
N2 - Hollow ceramic spheres are considered as an excellent buoyancy unit for deep-sea applications (> 5,000 m). However, there is no successful commercialization due to the low productivity of conventional slip casting because of the short life span of gypsum molds. In this work, we have developed single-use pulp-based molds for ceramic slip-casting applications. The developed robust pulp mold offers the advantage of being combustible in a controlled manner during the ceramic sintering process. The smooth, wrinkle-free inner surfaces, controlled water swelling, high wettability, and ability to retain shape during wet casting make the molds highly suitable for producing hollow ceramic spheres on an industrial scale. Alumina-based spheres with 52.8 mm diameter, 1.08 mm wall thickness, 0.46 g/cm3 density, and 54% buoyancy were successfully produced in pulp molds after sintering at 1630 °C. The spheres show exceptionally high hydrostatic failure pressures of above 200 MPa (> 20,000 m) and can be safely operated at depths greater than 5,000 m below sea level. We envision this approach to facilitate the mass production of ceramic spheres with the possibility of creating other complex-shaped ceramics via slip casting in pulp-based molds.
AB - Hollow ceramic spheres are considered as an excellent buoyancy unit for deep-sea applications (> 5,000 m). However, there is no successful commercialization due to the low productivity of conventional slip casting because of the short life span of gypsum molds. In this work, we have developed single-use pulp-based molds for ceramic slip-casting applications. The developed robust pulp mold offers the advantage of being combustible in a controlled manner during the ceramic sintering process. The smooth, wrinkle-free inner surfaces, controlled water swelling, high wettability, and ability to retain shape during wet casting make the molds highly suitable for producing hollow ceramic spheres on an industrial scale. Alumina-based spheres with 52.8 mm diameter, 1.08 mm wall thickness, 0.46 g/cm3 density, and 54% buoyancy were successfully produced in pulp molds after sintering at 1630 °C. The spheres show exceptionally high hydrostatic failure pressures of above 200 MPa (> 20,000 m) and can be safely operated at depths greater than 5,000 m below sea level. We envision this approach to facilitate the mass production of ceramic spheres with the possibility of creating other complex-shaped ceramics via slip casting in pulp-based molds.
KW - Deep-sea buoyancy modules
KW - Pulp-based molds
KW - Slip casting
KW - Thin-walled hollow sphere
UR - http://www.scopus.com/inward/record.url?scp=85120820591&partnerID=8YFLogxK
U2 - 10.1016/j.ceramint.2021.12.028
DO - 10.1016/j.ceramint.2021.12.028
M3 - Article
AN - SCOPUS:85120820591
SN - 0272-8842
VL - 48
SP - 8235
EP - 8244
JO - Ceramics International
JF - Ceramics International
IS - 6
ER -