Platinum Metals Review - Volume 30, Issue 3, 1986

To mark the fifteenth anniversary of the passing of a series of Amendments to the Clean Air Act by the Congress of the United States of America, the author, who was formerly Deputy Assistant Administrator for Mobile Source Air Pollution Control at the U.S. Environmental Protection Agency, reviews the benefits resulting from that legislation.

To increase our understanding of the electrochemical processes involved during cardiac stimulation by implanted pacemakers, alloys were prepared containing electrocatalytically active platinum group metals and either titanium or tantalum which irreversibly form very inactive oxides. Our work has shown that alloys with as little as 5 per cent platinum group metals exhibit electrochemical characteristics which are more similar to the platinum group metals than to the valve metals. Under some of the conditions certain of these alloys appear to be better electro-catalysts than the platinum group metals. Alloying titanium and tantalum with small amounts of platinum group metals also appears to prevent anodic dissolution of oxide-free titanium and tantalum.

Technical and economic considerations have identified an opportunity for composite materials which combine certain advantageous features of both noble and base metals. During an investigation of some platinum cladding techniques and of the properties of the resulting bimetals, data have been amassed which could have relevance to industrial as well as to decorative applications. Here the effects of deformation on the separate and the combined components are considered. A later paper will indicate how problems that may result from interdiffusion of the metals can be avoided.