Abstract In-situ Scanning Kelvin probe (SKP) measurements are used to follow the corrosion-driven cathodic delamination kinetics of model coatings comprising graphene nano-platelets (GNP) dispersed in polyvinylbutyral (PVB) adherent to iron and zinc (galvanised steel). To reduce delamination rates by >90% (relative to unpigmented PVB) a GNP volume fraction of 0.056 is required on iron but only 0.028 on zinc. On this basis, together with work function and O 2 permeability data it is proposed that the GNP acts principally to slow through-coating oxygen transport on iron; whereas on zinc a galvanic couple forms between zinc and GNP, displacing cathodic oxygen reduction.

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评价用于腐蚀控制的多层石墨烯纳米片复合涂层第二部分 - 阴极分层动力学

摘要 原位扫描开尔文探针 (SKP) 测量用于跟踪模型涂层的腐蚀驱动阴极分层动力学，该涂层包含分散在附着于铁和锌（镀锌钢）的聚乙烯醇缩丁醛 (PVB) 中的石墨烯纳米片 (GNP)。要将分层率降低 > 90%（相对于未着色 PVB），铁需要 0.056 的 GNP 体积分数，而锌仅需要 0.028。在此基础上，结合功函数和 O 2 渗透率数据，建议 GNP 主要用于减缓铁上的穿透涂层氧传输；而在锌上，锌和 GNP 之间形成电偶，取代阴极氧还原。