Preparation and characterization of silica-coated TiO2 nanoparticle

Park, Ok Kyung; Kang, Young Soo

doi:10.1016/j.colsurfa.2004.10.014

Cited by 91 publications

(64 citation statements)

References 8 publications

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“…The efficiency of magnetic-dielectric absorbers is high because the complex permittivity (ε΄-jε˝) and permeability (µ΄-jµ˝) differ from zero [4][5][6]. In general, the suitable values of RAM can be achieved by adding lossy fillers and/or magnetic particles to a light weight that are physically and chemically stable one and of course have a high ability to absorb electromagnetic wave radiation [7][8][9][10]. The composite approach has been used to improve various material properties, including mechanical, chemical, structural, optical and electrical/magnetic etc [11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Development of Radar Absorbing Nano Crystals under Thermal Irradiation

Sharma

Agarwala

2008

JNanoR

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) were synthesized by a modified flux method that combines the controlled chemical co-precipitation process for nucleation and complete uniform growth during in-situ annealing with NaCl flux under vacuum furnace. Uniform structure morphological transformation of nano crystals from spherical to prism faces were noticed after annealing with increasing temperatures from 200 to 1200 o C for 4 h in vacuum. XRD results showed the single phase nanocrystals of BaFe 18 O 27 with increasing crystallanity and size from 10 to 90 nm during annealing. FESEM and TEM were used to investigate the systematic growth processes of various morphologies of nano crystals. The effect of such systematic morphological transformation of nanocrystals was observed in dielectric, dynamic magnetic and refection loss (RL) properties in Kuband (12.4 -18.0 GHz). A significant increment from -15.23 dB to -43.65 dB with wide range of bandwidth in RL loss is noticed due to the symmetric morphological growth of single phase nano crystals of RAM during annealing. This process of crystal growth, morphology evolution and RL enhancement with respect to increasing temperature were also explained in terms of ostwald ripening and quantum size effect. IntroductionThe electromagnetic interference (EMI) problems have been attracting more attention recently due to the extensive growth in the application of electronic devices such as computer local area networks, mobiles phones, laptops, microwave oven etc [1][2][3]. EMI can cause severe interruption on electronically controlled systems. Furthermore, larger exposure to microwave energy can be potentially harmful to biological systems and human beings. To overcome EMI problems, it is suggested that electromagnetic wave absorbing materials with the capability of absorbing unwanted electromagnetic signals are to be used. For significant absorption of electromagnetic waves, the radar absorption material (RAM) should have electric and/or magnetic dipoles that interact with the electromagnetic fields in the radiation. Microwave absorption materials from magnetic to dielectric related materials used in a high frequency are particularly noticed. But, pure dielectric or magnetic materials are insufficient for absorbing radiation energy. The efficiency of magnetic-dielectric absorbers is high because the complex permittivity (ε΄-jε˝) and permeability (µ΄-jµ˝) differ from zero [4][5][6]. In general, the suitable values of RAM can be achieved by adding lossy fillers and/or magnetic particles to a light weight that are physically and chemically stable one and of course have a high ability to absorb electromagnetic wave radiation [7][8][9][10]. The composite approach has been used to improve various material properties, including mechanical, chemical, structural, optical and electrical/magnetic etc [11][12][13][14][15][16][17].

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Section: Introductionmentioning

confidence: 99%

Development of Radar Absorbing Nano Crystals under Thermal Irradiation

Sharma

Agarwala

2008

JNanoR

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“…As shown in Fig. 3, the binding energy of Ti 2p peak for HSi-TiO 2 is 459 eV, which is 2 eV lower than that of TiO 2 , induced by the formation of Si-O-Ti groups [20]. The Si-O-Ti bond in HSi-TiO 2 increases the electron density around Ti because the electronegativity of Si is weaker than that of H. Therefore, the shielding effect enhances, and thus the binding energy of Ti 2p decreases.…”

Section: Resultsmentioning

confidence: 92%

Fabrication of variable frequency motors using polyester-imide-hybridized resins and hyperbranched polysiloxane coated nano-TiO2

Zhou

Liang

2015

J Mater Sci

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The key for fabricating variable frequency motors is to develop high-performance resins that not only have excellent corona resistance and high breakdown strength, but also are suitable for vacuum pressure impregnation (VPI) technique; however, few resins simultaneously possess these features. Herein, a series of unique hybridized resins based on polyester-imide resin (EPEI) and hyperbranched polysiloxane coated nano-TiO 2 (HSi-TiO 2 ) were prepared, and their structure, processing characteristics, corona resistance, and high breakdown strength were investigated systematically. Results show that EPEI/HSi-TiO 2 -hybridized resins have excellent storage stability and are suitable for VPI, completely overcoming the disadvantages of traditional nanofiller-modified resins. In addition, the presence of HSi-TiO 2 changes the microstructure of crosslinked network, endowing EPEI/ HSi-TiO 2 -hybridized resins with outstanding corona resistance, high breakdown strength, and remarkably decreased partial discharge. The maximum corona-resistant life is 1586 min, about 57 times that of EPEI resin. As the content of HSi-TiO 2 increases, the breakdown strength of the hybridized resin increases, and the maximum value is 28.1 kV/mm, 15.2 % higher than that of EPEI resin. These attractive performance characteristics demonstrate that EPEI/HSi-TiO 2 -hybridized resins have great potential in fabricating variable frequency motors and high-performance electric equipments. The origin behind these attractive performance characteristics possessed by EPEI/ HSi-TiO 2 -hybridized resins was intensively discussed.

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“…The most common coating materials are hydrous alumina, silica, zirconia, and titania [8][9]. Other hydrous inorganic oxides used as the coating materials include tin, zinc, cerium, and boron oxides [1].…”

Section: Introductionmentioning

confidence: 99%

Preparation and film-growing mechanism of hydrous zirconia coated on TiO2

Sun

Wang

et al. 2010

Int J Miner Metall Mater

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To overcome the photochemical activity of rutile used as a pigment and improve its durability in application, hydrous zirconia-coated TiO 2 was prepared by the precipitation method. High-resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology and surface structure of hydrous zirconia-coated TiO 2 . The ζ-potential and ultraviolet (UV) absorption of both coated and uncoated rutile were examined. The results show that hydrous zirconia can not only improve the durability but also raise the lightness. A suitable ZrO 2 content of hydrous zirconia-coated TiO 2 is about 1.0wt%, and a dense film on the surface of rutile can be formed with better pigmentary properties. Based on the thermodynamic analysis, the zirconia-coating process and the film growth mechanism were discussed.

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Preparation and characterization of silica-coated TiO2 nanoparticle

Cited by 91 publications

References 8 publications

Development of Radar Absorbing Nano Crystals under Thermal Irradiation

Development of Radar Absorbing Nano Crystals under Thermal Irradiation

Fabrication of variable frequency motors using polyester-imide-hybridized resins and hyperbranched polysiloxane coated nano-TiO2

Preparation and film-growing mechanism of hydrous zirconia coated on TiO2

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