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91.
用氧乙炔焰加熔剂助熔一步法在12Cr1MoV珠光体耐热钢高温高压阀门密封面基体上喷熔Fe547B合金粉末,对喷熔工艺及喷熔层的硬度、时效硬化特性、热耐久性能、抗擦伤性能等性能进行了较系统的试验研究。证明用喷熔Fe547B合金粉末工艺修复电站高温高压阀门密封面裂纹是可行的。 相似文献
92.
Nikolaos Petsas Giorgos Kouzilos Giorgos Papapanos Michalis Vardavoulias Angeliki Moutsatsou 《Journal of Thermal Spray Technology》2007,16(2):214-219
The purpose of the present work was the investigation and characterization of the quality of air in a thermal spray industry,
in Greece. The activities that take place in the specific facility, as well as in most other similar industries, include thermal
spraying and several mechanical and metallurgical tasks that generate airborne particles, such as grit-blasting, cutting and
grinding of metallic components. Since the main focus of this work was the workers exposure to airborne particles and heavy
metals, portable air samplers with quartz fiber filters, were used daily for 8 h. Three samplers, carried from different employees,
were used for a period of 1 month. Results showed that both particles and heavy metals concentrations were low, even in the
production site, which was the most susceptible area. The only exceptions were observed in the case of cleaning and maintenance
activities in the thermal spray booth and in the case of spraying outside the booth. The main reason for the low concentrations
is the fact that most of the activities that could produce high-particle concentrations are conducted in closed, well-ventilated
systems. Statistical elaboration of results showed that particles are correlated with Ni, Cu, Co. The same conclusion is extracted
for Fe, Mn. These correlations indicate possible common sources. 相似文献
93.
采用棒材等离子喷涂法制备Fe72Cr8P13C7非晶态合金涂层,分析了涂层的组织,测定了晶化温度、显微硬度和结合强度,采用扫描电镜观察涂层的微观形貌和截面形貌,能谱分析涂层正面和截面的成分变化。结果表明,涂层组织致密,均匀,Cr、P在涂层中片状结构表面有富集现象,涂层与基材之间有冶金结合、机械结合的成型特征。 相似文献
94.
95.
S. Q. Fan G. J. Yang C. J. Li G. J. Liu C. X. Li L. Z. Zhang 《Journal of Thermal Spray Technology》2006,15(4):513-517
Control of the microstructure of TiO2 coatings through preparation methods significantly influences the coating performance. In this study, a vacuum cold-spray
process, as a new coating technology, is used to deposit nanocrystalline TiO2 coatings on conducting glass and stainless steel substrates. TiO2 deposits were formed using two types of nanocrystalline TiO2 powders with mean particle diameters of 200 and 25 nm. Coating microstructures were characterized by scanning electron microscopy
and x-ray diffraction analysis. Results demonstrate that a thick nanocrystalline TiO2 coating can be deposited by the vacuum cold-spray process. The coating was found to consist of particles stacked as agglomerates
that build up to several hundred nanometers. The coating also presents a mesoporous microstructure that could be effective
in such applications as photocatalytic degradation and dye-sensitized solar cells.
This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials
Park, OH, 2006. 相似文献
96.
To testify to the advantage of large ceramic powder spraying, numerical simulations and experimental studies on the behavior
of large yttria-stabilized zirconia (YSZ) powder in a high-power hybrid plasma spraying process have been carried out. Numeric
predictions and experimental results showed that, with the high radio frequency (RF) input power of 100 kW, the most refractory
YSZ powder with particle sizes as large as 88 μm could be fully melted and well-flattened splats could be formed. A large
degree of flattening (ξ) of 4.7 has been achieved. The improved adhesive strength between the large splat and the substrate
was confirmed based on the measurement of the crack density inside of the splats. A thick YSZ coating >300 μm was successfully
deposited on a large CoNiCrAlY-coated Inconel substrate (50×50×4 mm in size). The ultradense microstructure without clear
boundaries between the splats and the clean and crack-free interface between the top-coat and the bond-coat also indicate
the good adhesion. These results showed that highpower hybrid plasma spraying of large ceramic powder is a very promising
process for deposition of highquality coatings, especially in the application of thermal barrier coatings (TBCs). 相似文献
97.
Jong-Hyun Hwang Myoung-Seoup Han Dae-Young Kim Joong-Geun Youn 《Journal of Materials Engineering and Performance》2006,15(3):328-335
High-temperature wear characteristics between plasma spray coated piston rings and cylinder liners were investigated to find
the optimum combination of coating materials using the disc-on-plate reciprocating wear test in dry conditions. The disc and
plate represented the piston ring and the cylinder liner, respectively. Coating materials studied were Cr2O3-NiCr, Cr2O3-NiCr-Mo, and Cr3C2-NiCr-Mo. Plasma spray conditions for the coating materials were established adjusting stand-off distance to obtain a coating
with a porosity content of ∼5%. It was found that a dissimilar coating combination of Cr2O3-NiCr-Mo and Cr3C2-NiCr-Mo provided the best antiwear performance. The addition of molybdenum was found to be beneficial to improve the wear
resistance of the coating. Hardness differences between mating surfaces were also important factors in determining the wear
characteristics, so that it should be controlled below 300 in Vickers hardness under dry conditions. Adhesive wear accompanying
with metal transfer was a dominant wear mechanism for dry conditions. 相似文献
98.
A durable ceramic thermal barrier coating is applied directly to a smooth, highly oxidation resistant intermetallic alloy
in two layers. The first layer of ceramic is applied by low pressure plasma spraying and the second layer is applied by conventional
atmospheric pressure plasma spraying. This approach would allow the use of plasma sprayed ceramic coatings in applications
where a metallic bond coat is not desirable. 相似文献
99.
R. Etchart-Salas V. Rat J. F. Coudert P. Fauchais N. Caron K. Wittman S. Alexandre 《Journal of Thermal Spray Technology》2007,16(5-6):857-865
Direct current Suspension Plasma Spraying (SPS) allows depositing finely structured coatings. This article presents an analysis
of the influence of plasma instabilities on the yttria-stabilized suspension drops fragmentation. A particular attention is
paid to the treatment of suspension jet or drops according to the importance of voltage fluctuations (linked to those of the
arc root) and depending on the different spray parameters such as the plasma forming gas mixture composition and mass flow
rate and the suspension momentum. By observing the suspension drops injection with a fast shutter camera and a laser flash
sheet triggered by a defined transient voltage level of the plasma torch, the influence of plasma fluctuations on jet or drops
fragmentation is studied through the deviation and dispersion trajectories of droplets within the plasma jet.
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
100.
离心喷射沉积距离对TiAl基合金组织的影响 总被引:3,自引:0,他引:3
研究了γTiAl基合金经离心喷射沉积成形时不同喷射距离对合金组织的影响。合金经等离子弧熔炼并重熔后,在真空条件下进行离心喷射沉积成形,喷射沉积距离分别为200、300、400和500mm。结果表明,经离心喷射沉积后的合金仍存在着孔隙,且随喷射距离的增加,孔隙率增加,孔隙越细密。成形后的组织结构为层片状组织,其形貌、层片大小也随成形距离的不同而变化 相似文献