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181.
Plasma-sprayed thermal barrier coatings (TBCs) present a challenge for optical diagnostic methods to monitor TBC delamination, because the strong scattering exhibited by plasma-sprayed TBCs severely attenuates light transmitted through the TBC. This paper presents a new approach that indicates delamination in plasma-sprayed TBCs by utilizing a luminescent sublayer that produces significantly greater luminescence intensity from delaminated regions of the TBC. Freestanding coatings were produced with either a Eu-doped or Er-doped yttria-stabilized zirconia (YSZ) luminescent layer below a plasma-sprayed undoped YSZ layer. A NiCr backing layer was added to represent an attached substrate in some sections. For specimens with a Eu-doped YSZ luminescent sublayer, luminescence intensity maps showed excellent contrast between unbacked and NiCr-backed sections. Discernable contrast between unbacked and NiCr-backed sections was not observed for specimens with a Er-doped YSZ luminescent sublayer, because luminescence from Er impurities in the undoped YSZ layer overwhelmed luminescence originating from the Er-doped YSZ sublayer. 相似文献
182.
L. Xie M.R. Dorfman A. Cipitria S. Paul I.O. Golosnoy T.W. Clyne 《Journal of Thermal Spray Technology》2007,16(5-6):804-808
It has been found that reducing the level of impurity oxides (particularly SiO2 and Al2O3) in 7YSZ, from about 0.2 wt% to below 0.1 wt% raises the sintering resistance and the phase stability of plasma-sprayed coatings.
The implications for the usage of these coatings at elevated temperatures are examined. It is concluded that using relatively
high-purity powder of this type is likely to confer substantial benefits in terms of the thermomechanical stability of the
coatings under service conditions.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
183.
Isothermal oxidation of physical vapor deposited partially stabilized zirconia thermal barrier coatings 总被引:1,自引:0,他引:1
Y. H. Sohn R. R. Biederman R. D. Sisson 《Journal of Materials Engineering and Performance》1994,3(1):55-60
Thermal barrier coatings (TBCs), consisting of physical vapor deposited (PVD) partially stabilized zirconia (PSZ, 8 wt.%Y2O3) and a diffusion aluminide bond coat, were characterized as a function of time after oxidative isothermal heat treatment
at 1373 K in air. The experimental characterizations was conducted by X-ray diffraction analysis and scanning electron microscopy
(SEM) with energy-dispersive spectroscopy. During cooling to room temperature, spallation of the PSZ ceramic coatings occurred
after 200 and 350 h of isothermal heat treatment. This failure was always sudden and violent, with the TBC popping from the
substrate. The monoclinic phase of zirconia was first observed on the bottom surface of the PVD PSZ after 200 h of isothermal
heat treatment. The failure of TBCs occurred either in the bond coat oxidation products of αAl2O3 and rutile TiO2 or at the interface between the oxidation products and the diffusion aluminide bond coat or the PSZ coating. 相似文献
184.
Jae Woong Choi Gil Ho Hwang Won Kyu Han Sung Goon Kang 《Metals and Materials International》2006,12(1):75-80
Ni−B film of 1 μm thickness was electrolessly deposited on an electroplated Cu bus electrode. The film, which encapsulates
the Cu bus electrodes, prevents Cu oxidation and serves as a diffusion barrier against Cu contamination of the transparent
dielectric layer in a plasma display during the firing process at 580 °C. The microstructure of theas-deposited barrier film was amorphous phase and crystallized to Ni and Ni3B after annealing at 300 °C. The good barrier properties observed here can be explained by Ni3B precipitates at the grain boundaries acting as a fast diffusion path via pre-annealing at 300 °C before the firing process
at 580 °C. 相似文献
185.
福清市闽江调水工程输水隧洞,原地下水较活跃,后经水泥灌浆,堵住大部分水,但渗漏现象还比较严重,难以靠单一的水泥灌浆彻底堵住渗漏,后经采用PU4水溶性聚氨酯对漏水点进行化学灌浆取得了较好的止水效果。PU4水溶性聚氨酯是一种单组份灌浆材料,其遇水后自行分散、乳化、发泡,立即进行聚合反应,聚合后的固结体有良好的延伸性、弹性及抗渗性,体现了弹性止水和以水止水的双重功能。可供类似工程参考。 相似文献
186.
该文主要是通过朝面山水库防渗设计采用塑性混凝土防渗墙与防渗土工膜结合使用,根据模型计算分析可知,该方案防渗效果较好,是可行的、有效的防渗措施,可在水库加固中加以推广。 相似文献
187.
建设仿真性的防汛抢险训练场,提供有实战氛围的防汛抢险演练环境,在国内外尚属首次。为支撑江苏省防汛抢险训练场渗透破坏段方案设计,基于土体渗透破坏的基本理论并考虑到防汛演练的实际需求,首先确定用于堤坝填筑土料的料源,并对此进行了物理力学特性试验研究,根据粒径分布曲线推求非饱和渗流分析参数。然后开展两种不同比尺的水工模型渗透破坏试验,并与数值计算结果进行对比,验证数值分析的可靠性和合理性。最后对演练模型进行数值分析,根据上述试验和数值分析结果对设计方案提出相应的建议。上述设计方案基于均质土,实际填筑过程中土料的不均匀性较大,其合理性尚有待于实际工程的进一步验证。 相似文献
188.
根据覆盖层上水工建筑物实际运行状况及近年覆盖层上水工建筑物安全评价的实践,总结深覆盖层上水工建筑物坝址选择、坝轴线选择、枢纽布置、覆盖层复合地基的承载能力、各种型式防渗措施的防渗效果、防冲蚀、防地震液化处理措施及覆盖层应力、变形、渗流等特点。探讨覆盖层上水工建筑物的特点及存在的风险,并针对这些风险提出覆盖层上水工建筑物安全评价的关注点,以期在现有已取得巨大成就的基础上,进一步提高覆盖层上水工建筑物的设计、建设与安全评价水平。 相似文献
189.
190.
A wide view auto‐stereoscopic 3D display with an eye‐tracking system for enhanced horizontal viewing position and viewing distance
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Daichi Suzuki Shuji Hayashi Yosuke Hyodo Shinichiro Oka Takeo Koito Hiroki Sugiyama 《Journal of the Society for Information Display》2016,24(11):657-668
This paper describes the development of auto‐stereoscopic three‐dimensional (3D) display with an eye‐tracking system for not only the X‐axis (right–left) and Y‐axis (up–down) plane directions but also the Z‐axis (forward–backward) direction. In the past, the eye‐tracking 3D system for the XY‐axes plane directions that we had developed had a narrow 3D viewing space in the Z‐axis direction because of occurrence of 3D crosstalk variation on screen. The 3D crosstalk variation on screen was occurred when the viewer's eye position moved back and forth along the Z‐axis direction. The reason was that the liquid crystal (LC) barrier pitch was fixed and the LC barrier was able to control the only barrier aperture position. To solve this problem, we developed the LC barrier that is able to control the barrier pitch as well as the barrier aperture position in real time, corresponding to the viewer's eye position. As a result, the 3D viewing space has achieved to expand up to 320–1016 mm from the display surface in the Z‐axis direction and within a range of ±267 mm in the X‐axis direction. In terms of the Y‐axis direction, the viewing space is not necessary to be considered, because of a stripe‐shaped parallax barrier. 相似文献