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首页> 外文会议>Eurocorr 2004 >The use of the scanning Kelvin probe force microscopy andmicro capillary cell to investigate the local corrosion behaviourof 7xxx aluminium alloys
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The use of the scanning Kelvin probe force microscopy andmicro capillary cell to investigate the local corrosion behaviourof 7xxx aluminium alloys

机译：使用扫描开尔文探针力显微镜和微毛细管池研究7xxx铝合金的局部腐蚀行为

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Localised corrosion is a problem for the application of 7xxx high-strength aluminium alloys(Al-Zn-Mg-Cu) in the aerospace industry. It initiates at intermetallics containing Cu and Fedue to a strong galvanic coupling with the matrix. This causes local dissolution of the matrixaround the intermetallics (pitting), intergranular corrosion and exfoliation corrosion.The local corrosion behaviour of AA7075, AA7349 and an experimental alloy withcomposition in the range of AA7449 have been investigated by means of the scanning Kelvinprobe force microscopy (SKPFM) and the micro capillary cell. The SKPFM techniqueprovides a Volta potential map of the surface of the alloy, which is an indication of thecathodic or anodic behaviour of the intermetallics relative to the matrix. The micro capillarycell technique enables to measure the local breakdown potential of areas in the micrometerrange, containing a single intermetallic or a few intermetallics.It was found that Cu- and Fe-rich intermetallics are cathodic relative to the matrix and arecharacterised by a high Volta potential difference with the matrix (strong galvanic coupling).Their Volta potential difference with the matrix is dependent on the composition both of theintermetallics and of the matrix. Moreover, it is affected by heat treatments performed on thealloy. As an example, solution heat treated AA7075 shows a strong increase of the Voltapotential difference between the intermetallics and the matrix compared to AA7075-T6.Besides, it was found that the local breakdown potential of areas containing the intermetallicsis more cathodic for intermetallics with a higher Volta potential difference with the matrix.
机译：局部腐蚀是在航空航天工业中应用7xxx高强度铝合金（Al-Zn-Mg-Cu）的问题。它从含铜和铁的金属间化合物开始，与基体之间发生强电偶合。这会导致基体在金属间化合物周围发生局部溶解（点蚀），晶间腐蚀和剥落腐蚀。通过扫描Kelvinprobe力显微镜（SKPFM）研究了AA7075，AA7349和成分在AA7449范围内的实验合金的局部腐蚀行为）和微毛细血管。 SKPFM技术提供了合金表面的伏特电位图，该图表明了金属间化合物相对于基体的阴极或阳极行为。微毛细管电池技术能够测量微米范围内包含单个金属间化合物或少量金属间化合物的局部击穿电势，发现富含铜和铁的金属间化合物相对于基体为阴极，并具有高伏特电位与基质之间的差异（强电耦合）。它们与基质之间的伏特电位差取决于金属间化合物和基质的组成。而且，它受到对合金进行的热处理的影响。例如，固溶热处理的AA7075与AA7075-T6相比，金属间化合物与基体之间的电压差大大增加，此外，发现含有金属间化合物的区域的局部击穿电位对于具有较高金属间化合物的金属而言是阴极的伏特与矩阵的电位差。

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