Fig. 9 (;awe fabrication vn tl7e looms in the .Johnson Matthey Metals gaim shop. i~hf)f~ium-plfltiniLn~gauzes 7~p to 140 in (3.56 metres) wide (ire wot~eri from 0.003 in diamrtw wire
‘The development of these inactive surfaces is the subject of further research work and in a later article it is hoped that an explanation will be given of the fundamental causes that lie behind these observations.
Acknowledgements References The author is much indebted to Dr G. J. I<. I H. Connor, Z’latinum Metals Rev., 1967, 11, Acrcs for helpful discussions and to Mr J. G. (I), 2-9 Ibid.; (2), 60-69 lhy, who obtained the scanning electron micro- 2 T. EL Chilton, Chem. Engng. Prog. Mon. Ser. 3 scope and electron microprobe analyser photo- 3 A. W. Holmes, Platinum Metals Rev., 1959, 3, graphs. (I), 2-8
The Electrodeposition of Rhodium on Titanium The protection of titanium by a thin coating Titanium alloys were degreased chemically of platinum is well known in chemical and then were etched in sulphuric acid technology but, although platinised titanium solution at 60 to 90‘C before plating in a anodes are commonly used for industrial bath containing 1.2 to 2.0 g/l rhodium and electrochemical purposes, little attention has 40 to 50 g/1 sulphuric acid at current densities been given to titanium coated with other between 0.1 and 1.5 A/dm2 and at tem- platinum group metals. peratures between 20 and 75°C. Insoluble A recent paper by K. P. Ratashev and anodes of platinum and rhodium-plated V. P. Zverev ( TT.Leningrad. I’oiitekh. Inst., titanium were used and efficiency increased 1970, (304), 130-134)now reports on studies with lower current density and higher bath by the polarisation curve method of the temperature. electrodeposition of rhodium on titanium and The rhodium coatings obtained at low indicates the feasibility of such plating. It current density adhered well and were can produce both protective and decorative satisfactory as regards hardness, reflectivity coatings and also insoluble rhodium/titanium (brightness) and corrosion resistance. Tests anodes. The features of rhodium for these were carried out to determine the properties, purposes are its lesser density and greater strength and optimum thickness of rhodium hardness than platinum. coatings on insoluble titanium anodes.
Platinum Metals Rev., 19 7 1, 15, (2) 57