共查询到20条相似文献,搜索用时 328 毫秒
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通过搅拌摩擦加工(FSP)手段,对3 mm厚的AZ31镁合金板材作表面加工处理.然后在质量分数为5%的NaCl腐蚀溶液中添加不同浓度的碳酸钠作为缓蚀剂,通过动电位极化曲线以及交流阻抗(EIS)测试,研究了室温下该缓蚀剂对镁合金母材及搅拌摩擦加工处理镁合金电化学行为的影响.结果表明,添加缓蚀剂后,FSP镁合金及母材的腐蚀电流密度均减小,极化电阻及电荷转移电阻均增大,而且FSP镁合金的缓蚀效率要优于母材的缓蚀效率,且随浓度的增加而增加,碳酸钠是一种有效的无机缓蚀剂,并且其缓蚀作用效果与金属表面状态密切相关. 相似文献
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通过失重法、线性电位扫描、动电位扫描、电化学阻抗谱等分析手段,研究AZ63镁合金在NaCl溶液中的孔蚀行为,考察缓蚀剂磷酸钠和复配剂氟化钠对AZ63镁合金孔蚀的影响,并用扫描电镜观察AZ63镁合金的腐蚀形貌。结果表明:NaCl溶液浓度增加会使镁合金的孔蚀倾向增大,但NaCl质量分数超过5.5%后,击穿电位与再钝化电位差值的下降幅度显著减小;Na3PO4能够有效阻止AZ63镁合金在氯化钠溶液中的腐蚀,PO43-浓度增加使E b值增大,2.0%Na3PO4对镁合金的缓蚀率达到92.8%;NaF溶液与Na3PO4复配可减缓AZ63镁合金的腐蚀速度,添加0.16%NaF时,极化电阻增大至3092Ω·cm2。 相似文献
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用浸泡法在430不锈钢表面制备了十四烷基膦酸自组装膜,利用Fourier反射红外,动电位扫描、接触角测试、电化学阻抗及X射线光电子能谱研究了该自组装膜在430不锈钢表面的吸附行为和对点蚀电位的影响。结果表明:吸附有十四烷基膦酸分子的430不锈钢表面由亲水性转为疏水性,自组装时间为6 h时不锈钢的点蚀电位较高;氧化处理能够提高不锈钢基底的点蚀电位,且氧化处理后的不锈钢表面也能在十四烷基膦酸溶液中形成保护性的自组装膜。 相似文献
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AZ91D镁合金化学镀镍前处理工艺及腐蚀行为研究 总被引:1,自引:1,他引:0
为了改进传统的镁合金化学镀镍前处理工艺和确定以硫酸镍为主盐的镁合金化学镀镍的最佳工艺.采用碱性焦磷酸盐进行浸蚀代替铬酸浸蚀,去除合金表面的油污和氧化物;然后用氢氟酸溶液进行活化.通过正交试验确定了化学镀镍的最佳工艺.结果表明:采用碱性焦磷酸盐浸蚀的前处理工艺、在最佳施镀条件下镀2h,镀层厚度达到20μm,与基体结合良好;镀层为Ni-P微晶,表面平整、致密,磷的质量分数达11.7%.在质量分数为3.5%的NaCl溶液中的动电位极化测试结果表明,镀层可对AZ91D镁合金起到良好的防护作用. 相似文献
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V. S. Ivanova 《Metal Science and Heat Treatment》2005,47(7-8):305-311
A synergetic approach to solution of problems of self-controlled synthesis of nanostructures and creation of self-organizing
nanotechnologies is considered in connection with the superproblem of creation of materials with functional properties resembling
those of biosystems.
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Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005. 相似文献
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The importance of the self-diffusion of a metal during its oxidation by a gas is treated for the cases of nonstoichiometric oxides having either interstitial cation or cation vacancies. We have established a general relationship for the reaction rate when a mixed diffusion process occurs. From this relationship, we have shown that the pressure dependence can be different, according to whether the rate-determining process is the self-diffusion through the metal or through the product. 相似文献
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扫描电镜观察显示胫骨是一种由羟基磷灰石和胶原蛋白组成的自然生物陶瓷复合材料.羟基磷灰石具有层状的微结构并且平行于骨的表面排列.观察也显示这些羟基磷灰石层又是由许多羟基磷灰石片所组成,这些羟基磷灰石片具有长而薄的形状,也以平行的方式整齐排列.基于在胫骨中观察到的羟基磷灰石片的微结构特征,通过微结构模型分析及实验,研究了羟基磷灰石片平行排列微结构的最大拔出能.结果表明,羟基磷灰石片长而薄的形状以及平行排列方式增加了其最大拔出能,进而提高了骨的断裂韧性. 相似文献
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O. N. Vlasova N. N. Korneeva V. I. Eremenko O. Kh. Fatkullin N. M. Semenova S. N. Petrova D. D. Vaulin 《Metal Science and Heat Treatment》1991,33(12):924-931
Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991. 相似文献
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C. Colinet 《Intermetallics》2003,11(11-12):1095
A large number of ab-initio calculations of energies of formation of intermetallic compounds have been performed in the last 15 years. The currently used methods are listed. The paper presents a review of the aluminium based compounds which have been studied. Comparisons of calculated and experimental enthalpies of formation are provided for aluminim-3d and-4d transition metal alloys at equiatomic composition. The modelling of the enthalpies of mixing of solid solutions based on a given lattice is described. 相似文献
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洋务派在洋务学堂的办学活动中,为了解决西学专业学科的教学困难,采用了聘请外籍教师的应急措施.他们以真才实学,合同制管理作为主导思想,并认为这种解决师资的途径只是权宜之计,并非久远.从客观上看,洋务派的教师聘任思想有深刻的历史影响. 相似文献
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Simich-Lafitskii N. D. Koldaev A. V. Kraposhin V. S. Zaitsev A. I. Talis A. L. 《Metal Science and Heat Treatment》2020,61(11-12):675-680
Metal Science and Heat Treatment - The problem of formation of properties in microalloyed sheet steels is considered. The cause and the possible mechanism of precipitation of carbides of refractory... 相似文献
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《全面腐蚀控制》2015,(4)
NOx是大气环境的主要污染物之一,其主要来源为火力发电机组。依靠低氮燃烧技术,远达不到排放要求。选择性催化还原脱硝(简称SCR)技术是目前效率最高、最成熟、应用最广泛的电厂烟气脱硝技术。目前,在线氨逃逸监测技术存在诸多问题,影响了氨逃逸监测数据的准确度和稳定性。在燃料种类、炉膛结构、受热面布置、过量空气量、炉膛气流分布以及脱硝催化剂类型等条件确定的情况下,控制好氨加入量及其逃逸量是保证NOx脱除率的关键所在。燃煤锅炉除尘飞灰氨含量可侧面反映脱硝氨逃逸率的状况。根据国外的文献报道,正常情况下,电除尘灰中氨含量一般在50mg/kg-100mg/kg范围内。由于国内尚无灰中氨含量的测定方法,亦无脱硝运行对飞灰含氨量影响的数据积累。本文通过大量试验,确定了灰中氨溶解条件(如溶解时间、搅拌状态、灰水比、灰样量及其稳定性等),制定了灰中氨含量测定方法。 相似文献