PRICM-5

Volumes 475-479

doi: 10.4028/www.scientific.net/MSF.475-479

Paper Title Page

Authors: Akihiko Ito, Hiroshi Masumoto, Takashi Goto
Abstract: SrRuO3 (SRO) thin films were prepared by laser ablation. The optimum preparation condition of highly electrically conductive SRO thin films was investigated. The substrate temperature (Tsub) was changed from room temperature to 973 K, and the deposition atmosphere was at a high vacuum (P = 10-6 Pa) and in O2 at oxygen pressures (PO2) of 0.13 and 13 Pa. The films deposited at P = 10-6 Pa and PO2 = 0.13 Pa were amorphous structure. At Tsub > 573 K and PO2 = 13 Pa, well-crystallized pseudo-cubic SRO thin films with (110) orientation were obtained. With increasing Tsub, the conductivity of SRO films increased from 7.7×103 to 9.1×104 S·m-1. The epitaxially grown SRO films on (100) SrTiO3 substrates exhibited the highest conductivity of 1.8×105 S·m-1.
1209
Authors: Takashi Goto
Abstract: Thick oxide coatings have wide ranged applications such as oxidation protection, abrasives and thermal barrier coating (TBC). Yttria stabilized zirconia (YSZ) has been used for TBC in gas turbines. Generally, atmospheric plasma spray (APS) and electron-beam physical vapor deposition (EB-PVD) have been utilized in practical applications. Although chemical vapor deposition (CVD) provides high quality coatings, the deposition rate of CVD could have been too small for TBCs. We have recently developed a new laser CVD process achieving an extremely high deposition rate up to 660 ım/h for YSZ coatings on Al2O3 substrates and Ni-based super alloy substrates using Zr(dpm)4 and Y(dpm)3 precursors. An Nd:YAG laser with a high power of 250 W was introduced in a CVD chamber as a defocused beam in a diameter of 20mm covering a whole substrate surface. The YSZ coatings had a well-grown columnar structure with significant (200) orientation. Other oxides such as Y2O3, Al2O3 and TiO2 films were also prepared by laser CVD at high deposition rates around 1 mm/h.
1213
Authors: Rong Tu, Takashi Goto
Abstract: Titanium dioxide (TiO2) films were prepared on quartz substrates by using Ti(O-i-C3H7)2(dpm)2 and O2 gas. The crystal structure, morphology and deposition rate of TiO2 films were investigated by changing deposition temperatures (Tdep) from 700 to 1100 K and total pressures (Ptot) from 0.6 to 1.0 kPa. The structure changed mainly with deposition temperature. Rutile TiO2 films with (200) orientation and anatase TiO2 films with (004) orientation both in a single phase were obtained at Tdep = 873 K and 723 K, respectively. At Tdep > 873 K, the TiO2 films had a columnar microstructure consisting of mainly anatase and a small amount of rutile. At Tdep = 723 to 873 K, the TiO2 films were the mixture of non-oriented rutile and slightly (004) oriented anatase having dense and fine-grain microstructure. The deposition rate of TiO2 films increased with increasing Tdep showing the maximum of 30 µm h-1 at Tdep = 973 K and Ptot = 0.6 kPa.
1219
Authors: Ming Zhao, Da Ming Zhuang, Gong Zhang, Ling Fang, Min Sheng Wu
Abstract: The nitrogen-doped TiO2 thin films were prepared by mid-frequency alternative reactive magnetron sputtering technique. The N concentration of the nitrogen-doped TiO2 thin films was analyzed by XPS. And the absorption spectra of the films in ultraviolet and visible region were also investigated. The results show that the mid-frequency alternative reactive magnetron sputtering technique is a convenient method for growing TiO2-xNx. Annealing the nitrogen-doped TiO2 thin film in nitrogen atmosphere under 380°C is helpful for increase the concentration of nitrogen in the film, but the ratio of N2 in reactive gas is mainly influence the concentration of nitrogen in the Ti-N bond in the TiO2 film. The increase of the thickness of nitrogen-doped TiO2 films will enhance the absorbability of the film in the ultraviolet and visible region. The wavelength of the absorption edge of TiO2-xNx film with 1.5% nitrogen shift to 441nm from 387nm, which is the absorption edge for undoped TiO2 films.
1223
Authors: Feng Zhou, Kai Ming Liang, Hua Shao
Abstract: In this paper, the cracking behavior of sol-gel-derived SiO2-TiO2 films on glass-ceramics substrates is characterized by means of DTA, XRD and SEM. The SiO2-TiO2 films are deposited by sol-gel dip coating with tetrabutyl orthotitanate (Ti(OBu)4) and tetraethyl orthosilicate (TEOS) as raw precursors. The result shows that the cracking of the films is mainly related to the surface cleanliness of the substrate, the thermal expansion coefficients of the film and the substrate, the viscosity of the mixed sol, and the unbalanced stress produced during drying and heating process. The films without cracks were obtained by modifying the composition of sol and controlling the relative humidity and the heating rate of heat treatment.
1227
Authors: Hai Feng Li, Yong Huang, Zhi Jian Wan, Hou Xing Zhang, Y. Xu
Abstract: Various polycrystalline silicon thin films were deposited on Al2O3 ceramic substrates by RTCVD processing under different deposition conditions. The influence of deposition conditions on thin film quality was studied and a set of typical processing parameters were obtained, which would direct the RTCVD processing of thin film silicon solar cell technique.
1231
Authors: Ning Wang, Hong Lin, Jian Bao Li, Xiao Zhan Yang, Bo Chi
Abstract: Nanotube-shaped powders had been synthesized successfully from commercial anatasetype titanium dioxide powder by ion exchange approach. All nanotubes were open-ended with 3~5 nm in inner diameter, 8~12 nm in outside diameter and 200~400 nm in length. EDS result revealed that the nanotube was only composed of Ti and O. XPS analysis showed that two peaks located at 458.5 and 464.2 eV were assigned to Ti4+ in titanium dioxide. The formation mechanism of titanium dioxide nanotubes was also discussed in this paper.
1235
Authors: Zhi Peng Xie, Wei You Yang, He Zhuo Miao, Li Gong Zhang, Li Nan An
Abstract: A new method to synthesize Si3N4 nanostructures via catalyst-assisted polymeric precursor pyrolysis is present in this article. The as-prepared nanobelts are single crystals with a uniform thickness and width along the entire length, and contain no detectable defects such as dislocations or stacking faults. The thickness and width of Si3N4 nanobelts range from 40 to 60 nm and 600 to 1200 nm, respectively, and the lengths can be up to several millimeters. The growth directions of a-Si3N4 nanobelts are [101] and [100]. A solid-liquid-solid and gas-solid reaction/crystallization is proposed for the growth of S3N4 nonastructures.
1239
Authors: Tong Wei Lin, Wen Bin Cao, Jiang Tao Li, Chang Chun Ge
Abstract: Ti3SiC2/SiC ceramic composites with different content of SiC were synthesized through in-situ solid displacement reaction by hot pressing from starting mixture powders of TiC, Si and active carbon. The densities of the specimens were measured, the phase composition of the specimens was identified by XRD, and the microstructures were observed by SEM.
1243
Authors: Chun Qing Peng, Chang An Wang, Liang Qi, Yong Huang
Abstract: In this work, a new method to fabricate high-purity Ti3AlC2 powder by pressureless sintering (PLS) was reported through adding a little amount of B2O3 as a low-temperature aid. The elemental Ti, Al, and active carbon powders were used as raw materials with the molar ratio of 3 : 1.2 : 2. The effect of sintering temperature on the purity of Ti3AlC2 was investigated at the range of 800°C to 1400°C. The results showed that high-purity Ti3AlC2 powders, in which almost no TiC phase could be found, were stably fabricated by pressureless synthesis at 1400°C for 5 mins in flow Ar atmosphere. The roles of B2O3 addition were discussed in the paper.
1247

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