Would a 304 stainless tank be a good choice for an ammonium persulfate acid etch tank at a concentration of 10% by weight, mixed with deionized water, total fill of 125 gallons, not bubbled or agitated and at ambient temp? Or would 316 be needed? Or do I need to go to a plastic tank? This tank would also need a containment tank. The rest of the line would have a deionized water rinse station, a sodium bicarbonate solution station and finish off with a hot deionized water rinse station (190 °F).
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Brian Dalder Forum Moderator 175 Posts
Re: What material would be good for an ammonium persulfate acid etch tank?7 September 2011 at 1:29pmI took a quick look at Schweitzer's Corrosion Resistance Tables (5th edition) and type 304 stainless steel is not recommended for a 10% ammonium persulfate solution. The same source rates 316 stainless steel as "Good" (< 20 mpy) for 10% ammonium persulfate up to 380 °F. If you cannot tolerate this level of corrosion, your idea of moving to a plastic is a good one. Schweitzer rates many plastics as resistant even at elevated temperatures. For example, polypropylene is resistant up to 220 °F. Deionized water and sodium bicarbonate are not a concern with any of these materials.