Z.Q. Sheng and H. Xiao(National Key Laboratory for Nuclear Fuel and Material
,
Nuclear Power Institute of China
,
Chengdu 610041
,
China)Manuscript received in revised form 16 October 1998)
金属学报(英文版)
By means of TEM technique the orientation relationships of cementite, precipitated from islands of granular bainite during tempering, with ferrite have been objerved. By calculating the eigenvalue and eigenvector of transformation matrix, Isaichev relationship has been analyzed. The results indicate that Isaichev relationship indeed is the sum of Kungumov-Sachs relationship and Pitsch relationship, so the viempoint that the cementite with Isaichev relationship precipitates from austenite, instead of ferrite,is confirmed. Moreoven the matrix calculation shows that three reported orientation relationships among austenite, ferrite and cementite in pearlitic transformation cannot be simultaneously valid.
关键词:
orientation relationship
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Materials Science and Technology
In nuclear plant the protection of the H(2)BO(4) solution seal areas of AISI 316L austenitic steel is accomplished by Stellite 6 plasma cladding layer. Wear defects created in service required the part to be replaced or repaired. No existing repair technologies were practical. Electrospark deposition (ESD) was to repair defects, enabling the parts to be placed back in service. In this paper the authors report the results obtained depositing directly a layer of Stellite 6 alloy onto a 316L austenitic stainless and Stellite 6 plasma cladding layer by using ESD technique. Electrospark deposition can apply metallurgical bonded coatings without the need of post-heat treatment. Structure, hardness, chemical composition and morphology of the ESD coating have been analysed. By electrochemical measurements it is inferred that the corrosion resistance of the ESD coating is comparable to that of the 316L and Stellite 6 plasma cladding layer. The hardness improvement was ascribed to the refine microstructure and the rapid solidification.
关键词:
Electrospark deposition;AISI316L stainless steel;Plasma cladding;Stellite 6
B.W. Wang
,
H. Shen
金属学报(英文版)
Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.
关键词:
solar selective thin film
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null
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null
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Journal of Applied Physics
Reactive sputtering in an Al-O-2/Ar system equipped with a dc power supply in constant voltage mode was simulated using a kinetics model in this article. This work showed that reactive sputtering under reactive gas flow rate control and with a constant voltage power was much different from that with a constant current power both in time-dependent and parameter-dependent behaviors. Numerical analysis predicted the continuous, N-shaped V-I characteristics curves, which agreed with the experimental curves reported by other researchers in a system which was equipped with a dc constant current power but operated under voltage control [R. McMahon et al., J. Vac. Sci. Technol. 20 376 (1982); K. Steenbeck et al., Thin Solid Films 92, 371 (1982)] and in a system with a modulated power supply [H. Ohsaki et al., Thin Solid Films 281-282, 213 (1996)]. The continuous parameter-dependent functions indicated that there is no hysteresis effect in constant voltage reactive sputtering, which is a well-known feature of dc constant current magnetron sputtering of an Al-O-2/Ar system. According to the simulated kinetics curves using the same simulation parameters, the initial values of oxide coverage on the target surface had no influences on the final parameters at steady state in a constant voltage system, whereas different initial coverage may lead to different steady states (hysteresis behaviors) in a constant current system. This article showed that the films of any reactive gas contents, i.e., the M1-theta-(MOx)(theta) films (M=metal, MOx=compound of metal) with full range of 0 less than or equal to theta less than or equal to 1, could be produced in constant voltage reactive sputtering which is a system simpler than those under partial pressure control. (C) 1998 American Institute of Physics. [S0021-8979(98)03222-8].
关键词:
soft-x-ray;high-rate deposition;emission-spectroscopy;titanium;nitride;thin-films;in-situ;chemical-analysis;partial-pressure;pumping speed;magnetron
