Q: I chose Tantalum bolts for their corrosion resistance and high temperature capabilities and they are breaking. I’m running an application that fluctuates between 350 Celcius where there could be concentrated sulfuric acid contamination. I thought these would be excellent with high temperature acid exposure. Can you help me? I don’t understand.
A: The problem probably isn’t acid, it most likely has to do with embrittlement of tantalum at elevated temperatures (beyond 250°C) if you are running your process in has oxygen . Tantalum can actually be used in strong concentrations of most acids. It also has the capability to be used at temperatures up to 2000°C but only in a vacuum or inert gas. If it’s exposed to any oxygen or hydrogen it can suffer embrittlement at temperatures over 250°C. When tantalum embrittles it looses its ductility and can be susceptible to cracking or breaking. This could likely be your problem if you are not operating your process under a vacuum.