Study of variation in surface morphology, chemical composition, crystallinity and hardness of laser irradiated silver in dry and wet environments
Study of variation in surface morphology, chemical composition, crystallinity and hardness of laser irradiated silver in dry and wet environments
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DOI：
10.1016/j.optlastec.2017.01.002
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发表时间：
2017-07-01
影响因子：
5
通讯作者：
Hussain, Tousif
中科院分区：
文献类型：
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作者：
Ali, Nisar;Bashir, Shazia;Hussain, Tousif
研究了激光辐照银后，在干燥和潮湿环境中表面形貌、化学成分、结晶度和硬度的变化。为此目的，将银靶暴露于空气、乙醇和去离子水的周围环境中的各种激光脉冲数，即500、1000、1500和2000。利用扫描电子显微镜（SEM）研究了辐照后银的表面形貌。SEM分析揭示了干燥和潮湿环境下的显著表面变化。对于较低数量的脉冲，在空气环境中观察到显著的质量去除，但在乙醇的情况下，没有观察到表面形态的显著变化。在去离子水的情况下，观察到小尺寸的空腔，并形成具有球形顶端的突起。对于更高的激光脉冲数，在干烧蚀的情况下，观察到由冲击液化材料、小球和突起重新填充空腔。对于乙醇中的消融，观察到多孔和粗糙的周期性波纹，而对于去离子水，观察到更高数量的脉冲的突起的密度增加。EDS分析显示在两种环境条件下化学组成沿着氧的增强扩散的变化。利用X射线衍射（XRD）技术对暴露靶的晶体结构进行了研究。XRD结果支持EDS结果。在空气和乙醇的情况下形成Ag2O，而在去离子水的情况下形成Ag2O和Ag3O，证实了在照射后氧扩散到银表面中。采用维氏硬度计测量了激光处理后靶材的硬度。在干燥和潮湿的周围环境中辐照后观察到硬度增强。在空气环境中，随着激光脉冲数的增加，硬度先减小后增大。在乙醇的情况下，激光脉冲数的增加导致硬度的连续降低。然而，在去离子水的情况下，硬度随着激光脉冲数的增加而增加。
Variation in surface morphology, chemical composition, crystallinity and hardness of laser irradiated silver in dry and wet ambient environments has been investigated. For this purpose, the silver targets were exposed for various number of laser pulses in ambient environment of air, ethanol and de-ionized water for various number of laser pulses i.e. 500, 1000, 1500 and 2000. Scanning Electron Microscope (SEM) was employed to investigate the surface morphology of irradiated silver. SEM analysis reveals significant surface variations for both dry and wet ambient environments. For lower number of pulses, in air environment significant mass removal is observed but in case of ethanol no significant change hi surface morphology is observed. In case Of de-ionized water small sized cavities are observed with formation of protrusions with spherical top ends. For higher number of laser pulses, refilling of cavities by shock liquefied material, globules and protrusions are observed in case of dry ablation. For ablation in ethanol porous and coarse periodic ripples are observed whereas, for de ionized water increasing density of protrusions is observed for higher number of pulses. EDS analysis exhibits the variation in chemical composition along with art enhanced diffusion of oxygen under both ambient conditions. The crystal structure of the exposed targets were explored by X-ray Diffraction (XRD) technique. XRD results support the EDS results. Formation of Ag2O in case of air and ethanol whereas, Ag2O and Ag3O in case of de-ionized water confirms the diffusion of oxygen into the silver surface after irradiation. Vickers Hardness tester was employed to measure the hardness of laser treated targets. Enhanced hardness is observed after irradiation in both dry and wet ambient environments. Initial decrease and then increase in hardness is observed with increase in number of laser pulses in air environment. In case of ethanol, increase in number of laser pulses results in continuous decrease in hardness. Whereas, in case of de-ionized water hardness increases with increase in number of laser pulses.