Showing papers on "Sodium hypophosphite published in 1972"

Preparation and magnetic properties of cobalt alloy particles

Abstract: The preparation of submicroscopic chained cobalt and cobalt alloy particles by spontaneous autocatalytic reduction in protein solution has been studied. By varying the kind of protein, the average particle size can be easily varied from approximately 100 A to 500 A. The effects of the bath pH and hypophosphite content on the magnetic properties of the particles obtained are measured. It has been found that the coercive force can be increased at pH values from 8.0 to 8.5. However, coercive forces ranging from 300 Oe to 1000 Oe can be obtained by controlling the concentration of sodium hypophosphite. The rotational hysteresis integrals for the cobalt particles studied were in the range 1.2 to 1.8. These values are indicative of a single-domain chain of spheres model involving incoherent reversal.

Improvements in and relating to electroless plating

Abstract: 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.