Microstructure of LiAl5O8 and LiAlO2 Films Prepared by Laser CVD

2014 ◽  
Vol 616 ◽  
pp. 223-226
Author(s):  
Chen Chi ◽  
Hirokazu Katsui ◽  
Rong Tu ◽  
Takashi Goto

α-LiAl5O8, γ-LiAlO2, α-Al2O3and those composite films were prepared on AlN polycrystalline substrates by laser chemical vapor deposition (LCVD), and the effects of total pressure (Ptot) and the molar ratio of Li to Al (RLi/Al) on the morphology and deposition rates were investigated. The typical morphology of single-phase γ-LiAlO2films prepared atRLi/Al> 1.0 andPtot> 400 Pa was granular, whereas γ-LiAlO2films prepared atPtot< 200 Pa and γ-LiAlO2-α-LiAl5O8composite films had pyramidal grains. Single-phase α-LiAl5O8films showed polygonally faceted morphologies. Composite films of α-LiAl5O8and α-Al2O3consisted of carifllower-like and faceted grains. A single-phase γ-LiAlO2film deposited at 200 Pa showed the maximum deposition rate of 48 μm h-1.

2012 ◽  
Vol 508 ◽  
pp. 199-202
Author(s):  
Dong Yun Guo ◽  
Akihiko Ito ◽  
Rong Tu ◽  
Takashi Goto

Ba2TiO4 and Ba4Ti13O30 Thick Films Were Prepared by Laser Chemical Vapor Deposition Using Ba- and Ti-Dipivaloylmethanate Precursors. Single-Phase Ba2TiO4 Thick Films Were Obtained at 845–946 K and Ba/Ti Source Molar Ratio 2.4. Single-Phase Ba4Ti13O30 Films Were Obtained at 944–1011 K and Ba/Ti Source Molar Ratio 0.38. Ba2TiO4 Thick Films Consisted of Truncated Grains, while Ba4ti13o30 Thick Films Had Shellfish-Like Grains. Ba2TiO4 and Ba4Ti13O30 Thick Films Showed a Columnar Growth and their Deposition Rates Were 72 and 132 μm h−1, Respectively.


2012 ◽  
Vol 508 ◽  
pp. 207-210
Author(s):  
Akihiko Ito ◽  
Mitsutaka Sato ◽  
Takashi Goto

C-Axis-Oriented Y2Ba4Cu7O15-δ (Y247) Films Were Prepared on Multilayer-Coated Hasterolly Tape Substrate by Laser Chemical Vapor Deposition with Ultrasonically Nebulized Liquid Precursor. At a Low Precursor Concentration of 0.01 mol l−1 and Deposition Temperature of 933 K, Single-Phase Y247 Film with Significant c-Axis Orientation Was Obtained. At a Precursor Concentration of 0.1 mol l−1 and Deposition Temperature 983 K, a-Axis-Oriented YBa2Cu3O7-δ (Y123) Was Codeposited with C-Axis Oriented Y247 Film.


2014 ◽  
Vol 616 ◽  
pp. 141-144
Author(s):  
Chen Chi ◽  
Hirokazu Katsui ◽  
Rong Tu ◽  
Takashi Goto

(004)-oriented γ-LiAlO2films were prepared on poly-crystalline AlN substrates by laser chemical vapor deposition at deposition temperature (Tdep) of 1100–1250 K, molar ratio of Li/Al (RLi/Al) of 1.0–10 and low total pressure (Ptot) of 100–200 Pa. The (004)-oriented γ-LiAlO2films consisted of pyramidal grains with a columnar structure. The deposition rate of (004)-oriented γ-LiAlO2films reached to 65–72 μm h-1.


2012 ◽  
Vol 508 ◽  
pp. 3-6 ◽  
Author(s):  
Kadokura Hokuto ◽  
Akihiko Ito ◽  
Teiichi Kimura ◽  
Takashi Goto

Α-Al2O3 Films Were Prepared by Laser Chemical Vapor Deposition and the Effects of Precursor Evaporation Temperature (Tvap) and Oxygen Gas Flow Rate (FRo) on Phase and Orientation of Al2o3 Films Were Investigated. at Tvap = 413 K, (100)-Oriented α-Al2O3 and θ-Al2O3 Were Codeposited. the Amount of θ-Al2O3 Increased with Increasing FRo. at Tvap = 433–443 K, α-Al2O3 Films Showed a (001) Orientation. (100)- and (001)-Oriented α-Al2O3 Films Had a Rectangular- and Hexagonal-Shaped Grains, Respectively, and Showed a Columnar in Cross Section. Grain Size of (100)- and (001)-Oriented α-Al2O3 Films Decreased from 10 to 2 μm with Increasing FRo from 0.085 to 0.85 Pa m3 s−1. Deposition Rate Increased from 100 to 300 μm h−1 with Increasing Tvap from 413 to 443 K.


2011 ◽  
Vol 239-242 ◽  
pp. 318-321
Author(s):  
Yan Sheng Gong ◽  
Wei Zhou ◽  
Rong Tu ◽  
Takashi Goto

Nearly stoichiometric TiNxfilms were deposited on Al2O3substrates by laser enhanced chemical vapor deposition (CVD) with tetrakis (diethylamido) titanium (TDEAT) and ammonia as the source materials. Emphases were given on the effects of laser power (PL) and pre-heating temperature (Tpre) on the composition and deposition rate of TiNxfilms. Single phase of TiNxfilms with columnar cross section were obtained. The ratio of N to Ti in TiNxfilms increased with increasingPLand was close to stoichiometric atPL> 150 W. The deposition rate of TiNxfilms with a depositing area of 300 mm2was about 18-90 µm/h, which decreased with increasingPLandTpre.


2006 ◽  
Vol 317-318 ◽  
pp. 495-500 ◽  
Author(s):  
Takashi Goto ◽  
Teiichi Kimura

Thick oxide coatings have wide-ranged applications typically thermal barrier coatings. Although high speed deposition processes, often plasma spray or electron-beam physical vapor deposition, have been employed for these applications, another route has been pursued to improve the performance of coatings. We have proposed laser chemical vapor deposition (LCVD) for high-speed and thick oxide coatings. Conventional CVD can fabricate coatings at deposition rates of several to several 10 μm/h, and conventional LCVD has been mainly focused on thin film coatings and low temperature deposition. In the present LCVD, high-speed deposition rates ranging from 300 to 3000 μm/h have been achieved for several oxide coatings such as yttria stabilized zirconia (YSZ), TiO2, Al2O3 and Y2O3. This paper describes the effect of deposition conditions on the morphology and deposition rates for the preparation of YSZ and TiO2 by LCVD.


2011 ◽  
Vol 484 ◽  
pp. 172-176
Author(s):  
Yu You ◽  
Akihiko Ito ◽  
Rong Tu ◽  
Takashi Goto

Al2O3-AlN composite film was first prepared by laser chemical vapor deposition (laser CVD) using aluminum acetylacetonate (Al(acac)3) and ammonia (NH3) as source materials. The effects of NH3 on the crystal phase, composition and microstructure were investigated. The crystal phase changed from α-Al2O3 to AlN gradually with increasing the mole ratio of NH3 to Ar. Al2O3-AlN composite film was obtained at NH3/Ar ratio ranged from 0.09 to 0.16 (Tdep = 862–887 K), and AlN granular grains were embedded in between α-Al2O3 polyhedral grains.


2011 ◽  
Vol 484 ◽  
pp. 183-187 ◽  
Author(s):  
Pei Zhao ◽  
Akihiko Ito ◽  
Rong Tu ◽  
Takashi Goto

c-axis-oriented YBa2Cu3O7- films were prepared by laser chemical vapor deposition (laser CVD) using Y(DPM)3, Ba(DPM)2/Ba(TMOD)2 and Cu(DPM)2 as precursors with enhancement by a continuous wave Nd:YAG laser. YBa2Cu3O7- film almost in a single phase and that with different second phases of BaCuO2, CuBaO2, BaY2O4, CuYO2, Y2O3 and CuO were obtained by varying evaporation temperature of precursors. Ternary phase diagram as a function of evaporation amount of three precursors were obtained. The deposition rate of the c-axis-oriented YBCO film was 60 µmh-1, about 60–600 times higher than those of conventional CVD.


2012 ◽  
Vol 508 ◽  
pp. 279-282 ◽  
Author(s):  
Ming Gao ◽  
Akihiko Ito ◽  
Rong Tu ◽  
Takashi Goto

Titania (TiO2) Films Having Dense and Solid Microstructure Were Prepared by Laser Chemical Vapor Deposition Using CO2 Laser. The Effects of Deposition Temperature (Tdep) and Total Chamber Pressure (Ptot) on Phase and Microstructure of TiO2 Films Were Investigated. At Ptot = 600 Pa and Tdep = 790 K, Rutile TiO2 Film Had a Polygonal Platelet Grains 2 μm in Size. At Ptot = 600 Pa and Tdep = 1010 K, Rutile TiO2 Film Had (110) Orientation and Consisted of a Truncated Polyhedron 5–6 μm in Size. At Ptot = 200 Pa and Tdep = 955 K, Rutile TiO2 Film Has a Solid Columnar Having Faceted Surface. A Dense and Solid TiO2 Film Was Obtained at Ptot = 200 Pa and Tdep = 1120 K. The Deposition Rate of TiO2 Solid Film Was Reached 240 μm h−1.


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