阅读说明：本技术 复合金属结构的选择性磷化方法 (Selective phosphating method for composite metal structure ) 是由 O·达伦堡 H·韦特佐雷克 J·施佩希特 于 2019-02-12 设计创作，主要内容包括：本发明涉及一种复合金属结构的化学预处理和选择性磷化的方法,所述复合金属结构包括至少一个由铝制成的部分和至少一个由锌制成的部分,以及任选地由铁制成的另一部分,其中所述方法包括：(I)在第一步骤中,用含水锌磷化组合物处理复合金属结构,这导致在由铁和锌制成的零件上形成涂层重量为0.5-5g/m<Sup>2</Sup>的表面覆盖的结晶磷酸锌层,但不在铝零件上产生涂层重量为至少0.5g/m<Sup>2</Sup>的磷酸锌层,然后进行中间水洗操作,(II)在第二步骤中,将pH为2.0-5.5的含水酸性钝化组合物施加到复合金属结构上,其中所述酸性钝化组合物除去由锌和铁制成的零件上的不超过50％的结晶磷酸锌,但在铝零件上形成钝化层,该钝化层不构成表面覆盖的结晶磷酸盐层,其中步骤(I)中的锌磷化组合物包含一定含量的钠和/或钾离子和铝离子,其中步骤(I)中的锌磷化组合物的温度为20-65℃,且包含至少5mg/l但不大于200mg/l的游离氟离子含量,其中锌磷化组合物中存在以BF<Sub>4</Sub>计算,至少0.04g/l但不大于3.2g/l的水溶性无机化合物形式的硼,且其中锌磷化组合物中的加有KCl的游离酸点数为至少0.6点。本发明还涉及相应的锌磷化组合物、用于制备该组合物的浓缩物、相应的复合金属结构及其用途。(The invention relates to a method for the chemical pretreatment and selective phosphating of composite metal structures, includingAt least one part made of aluminium and at least one part made of zinc, and optionally another part made of iron, wherein the method comprises: (I) in a first step, the composite metal structure is treated with an aqueous zinc phosphating composition which results in a coating weight of 0.5 to 5g/m on a part made of iron and zinc 2 Without producing a coating weight of at least 0.5g/m on the aluminium part 2 And then an intermediate water washing operation, (II) in a second step, applying an aqueous acidic passivating composition having a pH of 2.0 to 5.5 to the composite metal structure, wherein the acidic passivating composition removes not more than 50% of the crystalline zinc phosphate on parts made of zinc and iron, but forms a passivation layer on aluminum parts, which passivation layer does not constitute a surface-covering crystalline phosphate layer, wherein the zinc phosphating composition in step (I) contains a content of sodium and/or potassium ions and aluminum ions, wherein the zinc phosphating composition in step (I) has a temperature of 20 to 65 ℃ and contains a free fluoride content of at least 5mg/l but not more than 200mg/l, wherein BF is present in the zinc phosphating composition 4 At least 0.04g/l but not more than 3.2g/l of boron is calculated as a water-soluble inorganic compound, and the number of free acid sites to which KCl is added in the zinc phosphating composition is at least 0.6 site. The invention also relates to the corresponding zinc phosphating composition, to a concentrate for preparing the composition, to the corresponding composite metal structure and to the use thereof.)