Papers by Keyword: NiCoCrAlY

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Authors: Raul Muñoz-Arroyo, Doris Clemens, Frank Tietz, Reiner Anton, Joe Quadakkers, Lorenz Singheiser
Authors: Yong Ho Sohn, N. Garimella, E. Perez, R.R. Mohanty, J. Liu
Abstract: Solid-state diffusion is a subject of great interest for many intellectual merits and practical applications. It also provides excellent educational studies with cross-fertilization of science and technology. This paper examines the importance of multicomponent-multiphase interdiffusion with specific examples from materials and coatings for components in advanced energy production systems, including gas turbines and nuclear reactors. Results and analysis from laboratory experiments are presented in terms of interdiffusion fluxes, integrated interdiffusion coefficients, effective interdiffusion coefficients, and average multicomponent interdiffusion coefficients. Applications are highlighted for materials and coatings for components in advanced energy production technologies. Additional consideration is given to the refined approach to assess composition-dependent interdiffusion coefficients in multicomponent alloys.
Authors: Xiang Bo Li
Abstract: In this paper, NiCoCrAlY coating was deposited by cold spraying with helium gas under the temperature of 500°C and pressure of 2.6 MPa. The microstructure of the coating was characterized through surface morphology and cross-sectional microstructure by scanning electron microscopy and X-ray diffraction analysis. The results showed that the coating is deposited through intensive plastic deformation of the spray particles by high-speed impact, and no oxygen phenomena discovered in the cold spray process. We also detected the micro-hardness using the Digital Vickers Microhardness Tester. Result revealed that a compact texture and high micro-hardness NiCoCrAlY coating can be obtained by cold spray.
Authors: Xian Xiu Mei, Cun Xia Wang, Wei Qu, Ying Qin, Chuang Dong, You Nian Wang
Abstract: In this paper, the NiCoCrAlY bond-coats was deposited onto the DZ4 nickel-based superalloy substrate by using low-pressure Plasma Spraying (LPPS) process, and then the coats were irradiated by high-current pulsed electron beam (HCPEB). Phase structures and microstructure of the HCPEB-treated NiCoCrAlY coating were analyzed by SEM, XRD and EDAX. The present results showed that the coating surface was remelted after HCPEB treatments, became smooth, had crater eruption, and the coating hadn’t produced distinct residual stresses. The results of the isothermal oxidations experiment performed in 900°C static air revealed that the oxidation resistance of the coating was enhanced obviously after HCPEB-treated and the oxides were mainly Aluminum-oxides, but without HCPEB-treated, the oxides of coating also had Nickel-oxides.
Authors: Qing Wu Meng, Lin Geng, Zhen Zhu Zheng
Abstract: Using a CO2 laser, a process of cladding Ni-base composite coating on Ti6Al4V with pre-placed B4C and NiCoCrAlY was studied. A good metallurgical bonding coating without cracks and pores was obtained in reasonable ratios of components and low energy laser process. Morphology and microstructure of the coating were analyzed with OM, XRD, SEM and EDS. It is certain that there was a reaction between B4C and Ti during in-situ producing TiB2 and TiC. The Ni-base composite coating is strengthened with TiB2 and TiC reinforcement phases. Vickers Hardness Tester measured that the average microhardness of the coating is HV1200 and it is 3.5 times of the Ti6Al4V substrate. The high hard coating containing several reinforcement phases greatly enhances wear resistance of titanium alloy.
Authors: Q.M. Wang, Y.J. Tang, Jian Zhang, Jun Gong, Chao Sun, Li Shi Wen
Authors: Jie Sun, Dan Zhao, Li Li Zhang, Yong Tan
Abstract: The protection of thermal parts has become one of the most important techniques with the development of high capability and high thrust-weight ratio for advanced aeroengine. In this paper, using the nickel base superalloy as the substrate, the thermal corrosion performances of NiCoCrAlY coatings using different thermal spraying methods, which consisted of high velocity oxy-fuel (HVOF), detonation spraying (DS), atmospheric plasma praying (APS) and low pressure plasma spraying (LPPS), were studied. The thermal oxidation experiments, which consisted of isothermal oxidation and cycling oxidation experiments were performed to character the thermal performances. From the results, it was shown that the NiCoCrAlY coatings prepared by high velocity oxy-fuel method were slight for 100 hours at 1100°C. The surface of the NiCoCrAlY coatings prepared by HVOF had a dense, continued Al2O3 oxide layer. Among all the methods to prepare NiCoCrAlY coatings, the method of high velocity oxy-fuel showed excellent performance.
Authors: Hong Yu Wang, Dun Wen Zuo, Xiang Feng Li, Yong Jun Chen
Abstract: Three NiCoCrAlY coatings strengthened by different contents of nano-SiCp (nanometric SiC particles)were prepared on Ni-based superalloy substrates using crosscurrent CO2 laser, and the thermal shock test of these coatings was conducted by cycling between 1050°C and room temperature (10-15°C). The spalled area in the oxide scale of coatings after 10 thermal shock cycles and the thermal shock cracks in the cross-section of coatings after 100 thermal shock cycles were investigated using SEM, OM, and other means. The results show that the thermal shock resistances of NiCoCrAlY coatings are improved after adding nano-SiCp. Among nano-SiCp-added coatings, the coating added with 1.0 wt% nano-SiCp performs best. After 10 thermal shock cycles, there is a slight spallation whose area is only 2.65% in the oxide scale of the coating; after 100 thermal shock cycles, no internal crack is observed in the cross-section, and the amount and size of propagating cracks are slight.
Authors: Klaus Fritscher, Christoph Leyens, Uwe Schulz
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