| 摘要 |
1457703 Electro-plating aluminium cylinders KIORITZ CORP 29 Nov 1974 [21 May 1974] 51823/74 Heading C7B In an Al-Si hyperentectic alloy cylinder, the finished machined (e.g. honed) sliding surface is pickled, e.g. in a solution containing H 3 PO 4 , H 2 SO 4 and HNO 3 , to remove from the surface to a given depth eutectic Al solid solution surrounding the primary crystal grains of Si which are not corroded and left intact, and the pickled surface is electro-plated with metal or alloy selected from Pb, Fe, Cu, Zn, Sn, Ni, Ag and alloys thereof e.g. Cu-Sn, to improve the sliding surface of electroplated metal or alloy and the top finished Si grains. Prior to pickling the surface may be trichloroethylene degreased, electrolytically degreased and rinsed. Prior to electro-plating the pickled surface may be rinsed, treated in a Zn chemical displacement liquid containing ZnO, NaOH, FeCl 3 , Rochell salt (KNa C4H406) and NaNO 3 , rinsed, treated with Cu striking liquid containing Cu 2 P 2 O 7 , K 4 P 2 O 7 and K 2 C 2 O 4 ÀH 2 O and rinsed. A Pb plating bath may contain Pb(BF 4 ) 2 , HBF 4 , H 3 BO 4 and glue; and an Fe plating bath may contain FeSO 4 ,(NH 4 ) 2 SO 4 and surfactant. |
