solution and procedure for application of a phophatueberzuges on metalloberflaechen

摘要

1368845 Phosphatising PYRENE CHEMICAL SERVICES Ltd 11 April 1973 [17 April 1972] 17606/72 Heading C7U An aqueous acidic phosphatising solution comprises (1) 2 to 20 g/l Zn, (2) 1 to 25 g/l Ca (3) 20 to 150 g/l NO 3 and (4) 3 to 20 g/l PO 4 , has a Zn:Ca wt. ratio of 0À2 to 10:1 and a NO 3 :PO 4 ratio of at least 2:1, and has a total acid content of at least 30 points; when the ratio NO 3 : PO 4 = 2 to 5:1, the ratio total acid points to free acid points is 5 to 8:1 and when NO 3 : PO 4 is greater than 5:1, said points ratio is 7 to 36:1. A concentrate for replenishment of the bath contains in weight parts 2-20 Zn, 1-25 Ca, 20-150 NO 3 , and 3-20 PO 4 , the ratio Zn:Ca being 0À2 to 10:1 and NO 3 : PO 4 being greater than 2:1. The bath may contain 0 to 2 g/l each of Ni and/or Co and 0 to 5 g/l of Mg, and 0-10 g/l of FSP-/SP when Al is treated; 0À1 to 0À3 g/l nitrite may be added at the start of the process. Fe, steel, Zn, Al and their alloys are treated at T # 55‹ C. for 1-30 minutes, preferably by dipping, to give a coating weight of 2 to 6 g/mSP2/SP.