Q: I’m using PEEK fasteners in hydrochloric acid but am seeing a slight bit of corrosion or degradation of the fastener. Can you recommend a better polymer for resistance?
A: For corrosion in HCL, a better choice may be PTFE screws. PTFE fasteners are virtually inert to most organics, acids and bases including HCl and far more corrosion resistant than PEEK. Like PEEK they are usable to about 500F, however the tradeoff is they won’t be as strong as PEEK. PEEK screws offer about 16,900psi of tensile strength where PTFE screws only offer about 3,900psi.