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近年来人们发现纳米尺度下金属/合金颗粒结构与性质很容易受外界环境影响.众多实验表明反应气体能够极大地影响合金纳米材料的表面偏析倾向,并进而影响其表面化学组分.但是另一方面,地球上最普遍的环境之一的水环境对于合金纳米材料的影响却少有人问津.在本工作中我们对NiMo合金在水分子、水团簇吸附情况下的表面偏析现象进行了第一性原理计算与蒙特卡洛模拟两方面的研究.通过第一性原理计算发现水分子、水团簇吸附都对NiMo合金偏析能有显著改变,并有可能改变其表面偏析倾向.通过进一步的蒙特卡洛模拟发现水环境对NiMo合金表面组分有着不可忽视的影响.通过这个工作我们希望人们能够重新审视水环境对合金偏析现象的影响.同时本工作对正确理解水-固界面相互作用和从微观角度理解合金腐蚀现象有着深远意义.
In recent years, it has been found that the structure and properties of metal / alloy particles in nanoscale are easily affected by the external environment.Many experiments show that the reaction gas can greatly affect the surface segregation tendency of alloy nanomaterials and thus affect the surface chemical composition.But another However, the influence of water environment, which is one of the most common environments on the earth, has little effect on the alloy nanomaterials.In this work, we first performed the surface segregation of NiMo alloy in the case of water molecules and water clusters Sexual principle calculation and Monte Carlo simulation.It is found by first-principles calculations that water molecule and water cluster adsorption have significant changes in the segregation energy of NiMo alloy and may change the segregation tendency of the NiMo alloy.Through further Monte-Carlo Carlo simulation found that the water environment on the NiMo alloy surface composition has a significant impact.Through this work we hope people can re-examine the impact of water environment on alloy segregation.At the same time this work to correctly understand the water-solid interface interaction and from Microscopic understanding of the phenomenon of alloy corrosion has far-reaching significance.