Silver-platinum alloys

Barnard, K. N., Christie, G. L. and Gage, D. G. Service Experience with Lead Silver Alloy Anodes in Cathodic Protection of Ships , Corrosion, 15, 11, 581-586 (1959) Peplow, D. B. and Shreir, L. L. Lead/Platinum Electrodes for Marine Applications , Corr. Tech. Apr. (1984)... 

Lead-platinum The alloy is lead together with 0-1-2% silver usually in rod form with platinum microelectrodes inserted every 150 mm. The purpose of these microelectrodes, which take the form of pins, is to stabilise the formation of lead peroxide on the anode surface. 

The industrial preparation of formaldehyde has occurred since the late 1800s and involves the catalytic oxidation of methanol 2CH,OH,. + 0 ,. —> 2CH 0,.. The oxidation takes place at temperatures between 400°C and 700°C in the presence of metal catalysts. Metals include silver, copper, molybdenum, platinum, and alloys of these metals. Formaldehyde is commonly used as an aqueous solution called formalin. Commercial formalin solutions vary between 37% and 50% formaldehyde. When formalin is prepared, it must be heated and a methanol must be added to prevent polymerization the final formalin solution contains between 5% and 15% alcohol. 

H. Palladium. Palladium (mp 1,SS2°C), is soft and ductile but work-hardens. At elevated temperatures, the diffusion of hydrogen through palladium is rapid, which forms the basis of a method for the purification of hydrogen. The best performance is obtained from a palladium-silver alloy containing about 18% silver because, unlike pure Pd, this alloy does not undergo a phase transition in the presence of hydrogen. Palladium is not as inert as platinum and is attacked by sulfuric and nitric acids. 

Amalgams. Liquid mercury is a fairly good solvent for all metals except iron and platinum. The alloys that are formed by dissolving metals in mercury are called amalgams, many of which involve inter-metallic compounds of the type MHg, where x is quite variable. Aside from their many applications in scientific work, amalgams are used in dentistry and in connection with the metallurgy of silver and gold. 

Silver.—Alloys of platinum and silver have received a considerable amount of attention owing to their importance in assaying. No definite compound of the two metals appears to be formed. ... 

Irioxide, platinum, silver, potassium chlorate, potassium ferricyanide, potassium mercuric cyanide, silver chloride, stibine, tellurium halides, tellurium hydropentachloride, tetramethy-lammonium amide, trimethylammonium amide, trioxygen difluoride, vinyl acetate. Violent polymerization with ethylene oxide. Attacks some coatings, plastics, and rubber. Attacks copper, brass, bronze, aluminum, steel, and their alloys. 

Surface areas of palladium and palladium-silver alloys were not measured. They were assumed to be about 2 m.Vg., because it was previously found that a similar preparation of platinum black had a surface area of... 

---