yapwx Wrote:Does anyone knows where to go to find the pH range where different coatings can resist, say ceramics, carbides, etc...? Or the different chemicals they can resist?
Thanks.
Several of the larger players Praxair, Sulzer have generated information over the years. However, this information tends to be proprietary to each company. What I can confirm is that Chrome Oxide is inert to most acids with the exception of Concentrated Hydrochloric Acid (37%) - the coating can become weight exhibited.
Surprisingly, the HVOF Tungsten Carbide Cobalt coatings are the next best with good resistence to most acids (Aluminium Suplhate, Halides, Hydrochloric acid, Sulphuric acid, Nitric acid, Ammonium Hydroxide)Tungsten Carbide Nickel Chrome and Tungsten Carbide Cobalt Chrome also providing good corrosion resistance especially in sour gas and chloride saturated environments. I would not recommend Tungsten Carbide Cobalt for chloride duty.
regards
Stewart