发布时间 : 星期日 文章HSC Chemistry使用手册Eh-pH Diagram模块中文更新完毕开始阅读
Fig. 2. Eh-pH Diagram of Fe-H2O-system at 25 °C. Molality of Fe is 10-6 M.
EpH Case 2:
Corrosion Inhibitors in Fe-Cr-H2O-system
Some elements or compounds may prevent corrosion even at very low content in the chemical system. These substances are called corrosion inhibitors and they can be divided into anodic and cathodic inhibitors. The anodic inhibitors primarily prevent the anodic reaction and passivate metals in this way, the latter ones suppress the corrosion rate by preventing the cathodic reaction or by reducing the cathodic area 13.
某些元素或化合物可以阻止甚至在化学系统中含量极低的腐蚀。这些物质称为缓蚀剂，
它们可分为阳极和阴极型缓蚀剂。阳极抑制剂主要是防止阳极钝化金属的反应，这样，后者抑制腐蚀率降低阴极面积13防止阴极反应或。 Chromate and dichromate ions are well known anodic corrosion inhibitors. Small amounts of
chromates will create a tight complex oxide film on the steel surface which prevents corrosion. The oxide film is mainly formed of magnetite (Fe3O4), hematite (Fe2O3) and chromic oxide (Cr2O3). 铬酸盐和重铬酸盐离子是众所周知的阳极腐蚀抑制剂。少量铬酸盐将创建一个致密复杂
氧化物薄膜在钢表面，防止腐蚀。氧化膜主要由磁铁矿（Fe3O4），赤铁矿（Fe2O3）和氧化铬（Cr2O3）。 The inhibitor behavior of chromates may be illustrated with Eh-pH-diagrams. The
Fe-Cr-H2O-system specifications are shown in Fig. 3. The calculation results for Fe-H2O and Fe-Cr-H2O-systems are shown in Figs 4 and 5. As shown in the diagrams, a large area in the corrosion region of iron Fe(+2a), Fig. 4, is covered by the Cr2O3 and Cr2FeO4 stability areas and thus protected from corrosion, Fig. 5. 铬酸盐缓蚀剂的行为可能与Eh-pH图说明。的fe-cr-h2o-system规格如图3所示。对于
Fe-H2O和fe-cr-h2o-systems计算结果在图4和图5所示。如图所示，在铁的腐蚀区域大面积（+ 2A），如图4所示，是由Cr2O3和cr2feo4稳定区域，从而保护免受腐蚀，如图5所示。 It is easy to create Eh-pH-diagrams with the EpH module. However, you should remember
that this type diagram greatly simplifies the real situation. They do not take into account, for example, the kinetic aspects or non-ideality of real solutions. Small errors in the basic thermochemical data may also have a visible effect on the location of the stability areas. In any case, these diagrams give valuable qualitative information of the chemical reactions in aqueous systems in brief and illustrative form. 它很容易创建与弗模块Eh-pH图。然而，你应该记住，这种类型的图，大大简化了实际
情况。他们没有考虑到，例如，动力方面或实数解的非理想性。在基本的热化学数据误差小，有可能对稳定区域的位置可见的效果。在任何情况下，这些图对化学反应有价值的定性信息在水系统简单说明的形式。
Fig. 3. Specification of Fe-H2O-system for EpH-diagram at 100 and 300 °C.
Fig. 4. Fe-H2O-system at 100 °C. Molality: Fe 10-2 M, pressure 1 bar.