Effects of Seeding with Nanocrystallites and Addition of Inorganic Alumina Sol on Crystallization of Alkoxide Alumina Gel

Abstract:

This paper reports a method for producing α-Al₂O₃ at low temperature from aluminum alkoxide using a combination of seeding of α-Al₂O₃ nanocryatallites and adding of inorganic alumina sol. An alkoxide alumina sol was obtained by hydrolyzing aluminum isopropoxide in water at 80°C and then peptizing the hydrolyzed aluminum isopropoxide using acetic acid at 80°C. An inorganic alumina sol was obtained by producing aluminum compound with a homogeneous precipitation method using aluminum nitrate and urea in aqueous solution and then peptizing the aluminum compound using acetic acid at room temperature. α-Al₂O₃ nanocrystallites were added to the alkoxide alumina sol containing the inorganic alumina sol. The addition of inorganic alumina sol provided successful fabrication of a crack-free α-Al₂O₃-seded alumina film by a spin-coating technique. The sol containing α-Al₂O₃ nanocrystallites was transformed to an α-Al₂O₃-seeded alumina gel by drying the sol at room temperature. The non-seeded alumina gel was crystallized into γ-Al₂O₃ at a temperature below 900°C. In contrast, the alumina seeded at 1% α-Al₂O₃ nanocrystallites content began to be transformed to α-Al₂O₃ by annealing at the temperature. The seeding and the adding promoted crystallization of the alumina gel into α-Al₂O₃. The promotion of crystallization was significant with an increase in α-Al₂O₃ nanocrystallites content by weight in the final seeded alumina gel.

• Periodical: Key Engineering Materials (Volume 697)
• Pages: 12-17
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.697.12
• Online since: July 2016
• Authors: Yoshio Kobayashi*, Yusuke Mabuchi, Masachika Hama, Katsumi Yamamura, Yusuke Yasuda, Toshiaki Morita
• Keywords: Alumina, Aluminum Alkoxide, Aluminum Salt, Crystallization, Seeding, Sol-Gel

References

[1] X. Shen, X. Nie, H. Hu, J. Tjong, Effects of coating thickness on thermal conductivities of alumina coatings and alumina/aluminum hybrid materials prepared using plasma electrolytic oxidation, Surf. Coat. Technol. 207 (2012) 96-101.

DOI: 10.1016/j.surfcoat.2012.06.009

[2] T. Shimizu, K. Matsuura, H. Furue, et al., Thermal conductivity of high porosity alumina refractory bricks made by a slurry gelation and foaming method, J. Eur. Ceram. Soc. 33 (2013) 3429-3435.

DOI: 10.1016/j.jeurceramsoc.2013.07.001

[3] W. Yu, H. Xie, L. Yin, J. Zhao, L. Xia, L. Chen, Exceptionally high thermal conductivity of thermal grease: Synergistic effects of graphene and alumina, Int. J. Therm. Sci. 91 (2015) 76-82.

DOI: 10.1016/j.ijthermalsci.2015.01.006

[4] K.T. Kim, T.D. Dao, H.M. Jeong, R.V. Anjanapura, T.M. Aminabhavi, Graphene coated with alumina and its utilization as a thermal conductivity enhancer for alumina sphere/thermoplastic polyurethane composite, Mater. Chem. Phys. 153 (2015) 291-300.

DOI: 10.1016/j.matchemphys.2015.01.016

[5] A. Comite, E.S. Cozza, G. Di Tanna, C. Mandolfino, F. Milellac, S. Vicini, Thermal barrier coatings based on alumina microparticles, Prog. Org. Coat. 78 (2015) 124-132.

DOI: 10.1016/j.porgcoat.2014.10.001

[6] A. Boumaza, A. Djelloul, F. Guerrab, Specific signatures of α-alumina powders prepared by calcination of boehmite or gibbsite, Powder Technol. 201 (2010) 177-180.

DOI: 10.1016/j.powtec.2010.03.036

[7] J. Kong, B. Chao, T. Wang, Y. Yan, Preparation of ultrafine spherical AlOOH and Al2O3 powders by aqueous precipitation method with mixed surfactants, Powder Technol. 229 (2012) 7-16.

DOI: 10.1016/j.powtec.2012.05.024

[8] S. -F. Wang, X. Xiangn, Q. -P. Ding, X. -L. Gao, C. -M. Liu, Z. -J. Li, X. -T. Zu, Size-controlled synthesis and photoluminescence of porou smonolithic a-alumina, Ceram. Int. 39 (2013) 2943-2948.

DOI: 10.1016/j.ceramint.2012.09.068

[9] G.C. Cunha, L. Pimenta C. Romão, Z.S. Macedo, Production of alpha-alumina nanoparticles using aquatic humic substances, Powder Technol. 254 (2014) 344-351.

DOI: 10.1016/j.powtec.2014.01.008

[10] C. Chen, Z. Ding, Q. Tan, H. Qi, Y. He, Preparation of nano α-alumina powder and wear resistance of nanoparticles reinforced composite coating, Powder Technol. 257 (2014) 83-87.

DOI: 10.1016/j.powtec.2014.02.059

[11] T. Tanase, A. Nishikata, Y. Iizuka, et al., Low temperature synthesis of single-phase lead zirconate titanate thin film with a nm-seeding technique J. Ceram. Soc. Jpn., 110 (2002) 911-915.

DOI: 10.2109/jcersj.110.911

[12] T. Tanase, Y. Kobayashi, T. Miwa, M. Konno, Low-temperature synthesis and dielectric properties of single-phase lead zirconate titanate thin film with a nano particle seeding technique Mater. Res. Soc. Symp. Proc. 784, C3. 32. 1-C3. 32. 6 (2004).

DOI: 10.1557/proc-784-c3.32

[13] T. Tanase, Y. Kobayashi, T. Nabatame, et al., Dielectric Properties of lead zirconate titanate thin films seeded with barium strontium titanate nanoparticles, Thin Solid Films 471 (2005) 71-75.

DOI: 10.1016/j.tsf.2004.04.048

[14] Y. Kobayashi, Y. Iizuka, T. Tanase, M. Konno, Low-temperature synthesis of single-phase barium strontium titanate thin film with a nm-Seeding technique and its dielectric properties, J. Sol-Gel Sci. Technol. 33 (2005) 315-321.

DOI: 10.1007/s10971-005-6382-y

[15] K. Inoue, M. Hama, Y. Kobayashi, Y. Yasuda, T. Morita, Low temperature synthesis of α-alumina with a seeding technique, ISRN Ceram. 2013 (2013) 317830.

DOI: 10.1155/2013/317830

[16] Y. Kobayashi, Y. Mabuchi, M. Hama, K. Inoue, Y. Yasuda, T. Morita, Seeding technique for lowering temperature during synthesis of α-alumina, J. Asian Ceram. Soc. 3 (2015) 139-143.

DOI: 10.1016/j.jascer.2014.12.004

[17] X. Wu, D. Wang, Z. Hua, G. Gu, Synthesis of γ-AlOOH (γ-Al2O3) self-encapsulated and hollow architectures, Mater. Chem. Phys., 109 (2008) 560-564.

DOI: 10.1016/j.matchemphys.2008.01.004

[18] K. Inoue, H. Kurebayashi, M. Hama, et al., Fabrication of transparent self-supporting alumina films by homogeneous precipitation process, J. Ceram. Soc. Jpn., 121 (2013) 494-497.

DOI: 10.2109/jcersj2.121.494

[19] A. Mahapatra, B.G. Mishra, G. Hota, Synthesis of ultra-fine α-Al2O3 fibers via electrospinning method, Ceram. Int., 37 (2011) 2329-2333.

DOI: 10.1016/j.ceramint.2011.03.028