| 摘要 |
1288103 Phosphating LUBRIZOL CORP 13 Aug 1970 [8 Oct 1968] 39114/70 Heading C7U An aqueous phosphating solution for zinc and ferrous metals contains (A) phosphate, 3-20g/l (B) zinc, 0À5-3g/l, (C) Ni, Co, or Cu, 0À05-3À0, 0À003-0À7 or 0À003-0À04g/l respectively, (D) Mg, 1-8g/l (E) nitrite, 0À01-0À25 g/l and (F) fluoride and/or chloride, 0À09-3À0 and/or 2-30g/l respectively. Sources of the components may be (A) H 3 PO 4 , pyro- or poly-phosphoric acid, Na 1 -K 1 - or NH 4 - dihydrogen phosphate (B) ZnO, Zn(NO 3 ) 2 or ZnSiF 6 (C) soluble salts, preferably nitrates, Ni being preferred, (D) MgO, Mg(NO 3 ) 2 or MgCl 2 , (E) Na-, K-, or Mgnitrite and (F) the Na, K, NH 4 , or Mg salts, or in addition for fluoride, a fluosilicate or fluoborate. Nitrate ion, up to 40g/l may be added, e.g. incidental to the Zn or Ni ions. The solution may be adjusted to 5 to 30 points total acidity, and 0À1 to 5 points free acidity. The composition may be provided as one or more concentrates, (nitritefree to prevent decomposition) or as a dilute solution, and a surfactant may be added, e.g. an ethylene oxide condensate, sodium alkyl sulphate or sulphonated hydrocarbon. Application is by conventional methods to a surface which has been preferably cleaned with a solution containing Ti phosphate, application being at room temperature to 240‹ F. for 5 sacs-10 min, giving a coating with weight 25-1000 mg/sq. ft. and a modified hopeite structure. Following phosphating, articles may be rinsed in a solution of metal chromate or dichromate, chromic acid/H 3 PO 4 , chromic acid/dichromate, or partially reduced chromic acid. |
