Steel articles are protected against corrosion by being completely or partially coated with a material showing a resistivity of at least 0.1 M OMEGA .cm and comprising a matrix which comprises… A) inorganic solid particles of a size of from about 5 mu m to about 0.5 mu um, or a coherent structure from such homogeneously arranged particles, and… B) densely packed solid particles having a size of the order of 0.5 - 100 mu m and being at least one order of magnitude larger than the respective particles stated under A), or a coherent structure formed from such densely packed particles, the particles B preferably being Portland cement particles.… Particles A are preferably ultrafine silica particles formed by growth from vapour phase and are substantially densely packed in the voids between the particles B. Particles A are especially present in an amount of 10 - 30% by volume, calculated on the combined volume of the particles A + B Composite material for forming the matrix typically comprises Portland cement, ultrafine silica, water in low proportion, and a concrete superplasticizer in high proportion, optionally with additional bodies such as fibers or mica, and is easily shapeable and also suitable for underwater application. Resistivity of the coating material is in the range of 0.3 - 10 M OMEGA cm, typically at least 1 M OMEGA .cm. Development of resistivity accelerates when curing is performed at elevated temperature. Steel article may, e.g., be one in which the stell receives cathodic protection, or a pipe connector which comprises a pair of axially spaced tubular bodies interconnected by said coating material.
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机译：通过用电阻率至少为0.1 M OMEGA.cm的材料完全或部分涂覆并包含基质构成的钢制品，以防止腐蚀，该基质包含以下成分：A）尺寸约为5微米至约0.5的无机固体颗粒或由这种均匀排列的颗粒组成的凝聚结构，以及……B）密度大的固体颗粒，其大小为0.5-100微米，并且比A）中所述的各个颗粒至少大一个数量级或由这种致密堆积的颗粒形成的凝聚结构，颗粒B优选为硅酸盐水泥颗粒。…颗粒A优选为由气相生长而形成的超细二氧化硅颗粒，并且基本上致密地堆积在颗粒B之间的空隙中。颗粒A以颗粒A + B的总体积计算，其含量通常为10-30％（体积）艾西斯波特兰水泥，超细二氧化硅，低比例的水和高比例的混凝土高效减水剂，还可以选择添加其他纤维或云母之类的物质，易于成型，也适用于水下应用。涂层材料的电阻率在0.3-10 M OMEGA cm的范围内，通常至少为1 M OMEGA .cm。当在高温下进行固化时，电阻率的发展加速。钢制品可以是例如其中钢柱受到阴极保护的钢制品，或者是包括通过所述涂层材料相互连接的一对轴向间隔开的管状体的管道连接器。
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