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991.
Shigeji Taniguchi Toshio Shibata Naoyuki Asanuma Hanyi Lou Fuhui Wang Weitao Wu 《Oxidation of Metals》1993,39(5-6):457-473
The oxidation behavior of TiAl coupons coated with a fine-grain Co-30Cr-4Al (mass %) film of about 30-m thickness has been studied at 1100–1400 K in a flow of purified oxygen at atmospheric pressure for up to 500 ks. Three oxidation stages were recognized: initial transient, parabolic, and accelerated stages. However, at 1100 K a parabolic stage continues for more than 800 ks. The activation energy for parabolic oxidation agrees with reported values for the oxidation of alumina-former alloys, although the mass gains during the parabolic stages are relatively small at 1200 and 1300 K. Micropores developed mainly at the scale/coating and coating/substrate interfaces as oxidation proceeded. This is attributable to recrystallization of the coating during oxidation and a Kirkendall effect due to preferential diffusion of Co into the substrate. The accelerated oxidation can be explained in terms of the formation of rutile mounds on the scale. 相似文献
992.
Jeong-Seb Han 《Corrosion Science》2004,46(4):787-793
The application of an infrared camera for detecting corrosion under organic coatings was studied. The ruptured blistering area, blister and filiform corrosion can be monitored easily by infrared thermography. When the corroded specimen is heated, the temperature at the surface over the corroded area changed differently according to the type of corrosion.The extent of increase in temperature was in the following sequence: ruptured blister > filiform filament > intact part > blister.From the analysis of temperature distribution at the surface of specimen, the location, shape and size of the corroded area can be estimated. 相似文献
993.
本文全面地研究了淬火温度和回火温度对25CrNiWV钢力学性能及金相组织的影响,确定了此钢种的最佳热处理工艺。 相似文献
994.
Numerical simulation of gas metal arc welding temperature field 总被引:1,自引:0,他引:1
The infrared camera is used to investigate the temperature field of gas metal arc welding.The results show that the temperature distribution of weld pool and adjacent area appears cone shape.A new heat source model combined by Gaussian distribution heat source of the arc and conical distribution heat source of the droplet is set up based on the experimental results, and with the combined boundary conditions,the temperature field of gas metal arc welding is simulated using finite element method.According to the comparison between the results of experiment and simulation in temperature field shows that the new combined heat source model is more accurate and effective than the Gauss heat source model. 相似文献
995.
Jooho Hwang Chun-Hong Park Chan-Hong Lee Seung-Woo Kim 《International Journal of Machine Tools and Manufacture》2006,46(7-8):801-810
This paper describes an estimation and correction method for the two-dimensional (2D) position errors of a planar XY stage that is driven along the Y-axis by two linear motors. The 2D position errors of the stage were estimated and corrected based on measured motion errors from a conventional laser interferometer system. To compensate for the planar XY stage 2D position errors, corrections were introduced for the yaw, perpendicular, straightness and 1D position errors along each axis, which are predominantly caused by linear scale, yaw, and pitching motion errors. The effect of the motion error corrections was evaluated by diagonal measurements based on the ISO230-6 standard and six different 1D position error measurements along the X and Y-axes. By applying error motion corrections, the diagonal systematic deviation at the center point was improved from 499.7 μm to 1.16 μm, and the estimated maximum 2D position errors were improved to −0.263 and 0.530 μm in the X and Y directions, respectively. The diagonal systematic deviation at a corner point was 1.23 μm and the estimated maximum difference between the corner and center points improved from −2.603 and 2.603 μm to −0.05 and 0.12 μm in the X and Y directions respectively. 相似文献
996.
997.
对利用原位反应与高剪切液态搅拌复合专利技术制备的Al3Ti-TiB2-SiC/Al-13%Si复合材料的增强相的形成热力学进行了理论计算和分析,并采用差热分析法(DTA)进行了试验验证.研究表明:(1)Al-Ti-B体系加入到Al-13%Si熔体中可发生原位反应,形成增强相,原位反应的开始温度为905.3℃,结束温度为1 061.23℃;(2)Al-Ti-B体系加入到Al-13%Si熔体中,制备颗粒增强Al-13%Si复合材料的增强相为TiB2和Al3Ti,但TiB2形成能力最强. 相似文献
998.
999.
An iron electrode was modified by electrolytic reduction in deaerated acetonitrile solution of p-toluenediazonium tetrafluoroborate CH3C6H4N2BF4 (TDFB) or p-hydroxymethylbenzenediazonium tetrafluoroborate HOCH2C6H4N2BF4 (HOTDFB) below 10 °C to form a self-assembled monolayer (SAM) of toluene CH3C6H4- or hydroxymethylbenzene HOCH2C6H4- (HOMB) moiety, probably adsorbed on the electrode by the formation of a covalent bond between carbon and iron atoms, as shown in references. The protective ability of the layer was examined by polarization measurement of the electrode in an aerated 0.5 M NaCl solution. The protective efficiencies of these two SAMs were not high, around 30%, a little higher than that of the toluenethiol CH3C6H4SH SAM which was anchored on iron via a coordinate bond between sulfur and iron atoms. The iron surfaces modified with TDFB and HOTDFB were characterized by contact angle measurement, FTIR reflection spectroscopy and X-ray photoelectron spectroscopy. The persistence in protection of iron against corrosion by coverage with the HOMB SAM was confirmed by polarization measurements after immersion in 0.5 M NaCl for a long period of the time. 相似文献
1000.