Johnson & Johnson electrocauterization device corrosion failure

Cardiac surgery cautery probes corroded under 100V across all metal candidates (stainless, nickel alloys, even platinum and gold). Tom's recommendation: make the tip disposable.

If we go back to the Pourbaix diagram, you can decompose virtually any metal with two or three volts. I was working with Johnson & Johnson back in the '80s, and they use electric cautery to cauterize a wound. They go in there with a couple of electrodes and 100 volts, pass the current through your skin, and it basically dries up the blood and the proteins. In cardiac surgery, you've got a leaky vein or something, blood all over. What's to stop the bleeding? They go in there with these two little probes, put a hundred volts there, and essentially clot the blood right there locally. But one's positive, one's negative, and the anode — which is positive — was always corroding. 100 volts will corrode any metal. They were using stainless steel and nickel alloys, and all of them were corroding. What are we going to use? I said nothing. Because if it's a metal, two volts will corrode any metal. Not even platinum — you name it — because of the thermodynamic immunity, you can't get the stability of the oxide or anything else.

Closing case for the voltage-and-bond-energy section. 100 V DC pitting on stainless steel tips at the anode; platinum tops out around 2 V, titanium around 5 V; bond-strength limit is the materials-science answer to a customer demanding a 100 V-corrosion-resistant tip.

I once consulted for a division of Johnson [Ethicon, J&J], and they make medical instruments for all kinds of surgery. At the time, one of the big things was electrocauterization. Someone's doing an operation, they cut through an artery, and they want to cauterize that wound — essentially weld that blood vessel back together. Hey, it's a welding problem.