The surface of a substrate is roughened by providing a substrate which comprises a resinous material and an inorganic particulate material; and etching a surface of the substrate to selectively etch the resinous material and thereby produce the roughened surface.

Roughening surface of a substrate

1,268,807. Plating plastics with metals. M. L. ALKAN Ltd. Aug. 13, 1970 [Aug. 1, 1969], No. 38796/69. Headings C7B and C7F. An A.B.S. article is plated, whilst held in a jig coated with a plastics other than A.B.S. e.g. p.v.c., polyethylene or p.t.f.e., by etching in e.g. H 2 SO 4 and chromium trioxide with or without phosphoric acid, catalysing in a compound of Pd, Ag, Au, Pt, Rh or Ir dissolved in H 2 SO 4 , reducing the metal compound in e.g. sodium hypophosphite or borohydride, an amine borane, formaldehyde, hydrazine or hydroxylamine, electroless plating with Cu, Ni or Co, and finally electro-plating with Cu, Ni or Co. Examples of electroless baths are (g. /1.): - NiCl 2 30, sodium citrate 15, NaH 2 PO 2 25, sodium acetate 20, and copper sulphate 10, Rochelle salt 40, formaldehyde 40 ml/l., caustic soda 20, and e.d.t.a. 0A5. A Ni electro-plating bath may comprise (g. /1.) NiSO 4 . 6H 2 O 250, NiCl 2 .6H 2 O 62 and H 3 BO 3 44 (pH 4A0) using a current density of 40 A/ft 2 and a temperature of 55‹ C.

Upcott David George

Papers

Improvements in and relating to electroless plating