Anodizing, conversion & passivation · finish comparison
Citric Acid Passivation vs Stainless Steel Pickling
Citric Acid Passivation and Stainless Steel Pickling are both passivation & electropolishing finishes; citric passivation resists corrosion better.
Citric Acid Passivation
Passivation & electropolishing · $
Citric-acid passivation is a separately searched and specified stainless-steel passivation route that removes free iron without nitric acid.
Stainless Steel Pickling
Passivation & electropolishing · $ · instant quote
Pickling chemically removes weld heat tint, oxide scale, and the chromium-depleted metal beneath it from stainless steel.
When to choose which
Choose Citric passivation
Citric passivation is the pick when its strengths below matter more than Stainless pickling's.
- Adds 0 µm measurable buildup
- Avoids nitric-acid fumes and nitrate waste
- ASTM A967 provides multiple citric treatment windows
Choose Stainless pickling
Choose Stainless pickling when heat tint must first be removed.
- Removes weld heat tint that passivation alone cannot remove
- Eliminates oxide scale and embedded iron contamination
- Restores a clean surface before controlled passivation
What the numbers say
- Citric passivation resists corrosion better.
- Citric passivation is the lower-cost option ($).
Scores side by side
Each score is 0–100 against every finish in this catalog. Corrosion is derived from salt-spray test duration and surface hardness from the finish layer's Vickers hardness where a measured figure exists; a finish that leaves the base metal's own surface is not rated for hardness. Cosmetic, lubricity and cost are FabDigit's engineering assessment. Scores and typical figures are screening data, not matched side-by-side tests or service-life rankings; ASTM B117 is a controlled salt-fog method, not a field-life prediction.
| Score | Citric passivation | Stainless pickling |
|---|---|---|
| Corrosion resistance | 34 Low | 28 Low |
| Surface hardness / wear | — — | — — |
| Cosmetic quality | 18 Low | 20 Low |
| Lubricity | 10 Minimal | 10 Minimal |
| Cost | 12 $ | 12 $ |
Key numbers
| Property | Citric passivation | Stainless pickling |
|---|---|---|
| Thickness | 0 µm | 0 µm |
| Electrical | Unchanged | Unchanged |
| Relative cost | Budget ($) | Budget ($) |
| Added lead time | 2–4 working days | 2–5 working days |
| RoHS | Compliant | Compliant |
| Instant quote | On request | Yes |
Bold marks the side that is ahead on a row where more (or less, for cost and lead time) is better. Ranges are the typical specification window; the drawing call-out fixes the class.
Which materials take each finish
| Material family | Citric passivation | Stainless pickling |
|---|---|---|
| Stainless Steel | Yes | Yes |
| DMLS / SLM | With care | With care |
| Titanium | Limited | Limited |
Specifications and drawing call-outs
Citric passivation
- ASTM A967 — Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts
- AMS 2700 — Passivation of Corrosion Resistant Steels
PASSIVATE PER ASTM A967, CITRIC 2; VERIFY BY HIGH-HUMIDITY TEST; NO VISIBLE ETCHING, PITTING, OR STAINING
Stainless pickling
- ASTM A380 — Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems
PICKLE STAINLESS STEEL WELDMENTS PER ASTM A380 TO REMOVE ALL HEAT TINT AND SCALE, THEN PASSIVATE PER ASTM A967 CITRIC 2
Citric passivation vs Stainless pickling — frequently asked
What is the difference between Citric passivation and Stainless pickling?
Citric Acid Passivation and Stainless Steel Pickling are both passivation & electropolishing finishes; citric passivation resists corrosion better. Citric passivation is the lower-cost option ($).
When should I use Citric passivation instead of Stainless pickling?
Conversely: choose Stainless pickling when heat tint must first be removed.
Is Citric passivation or Stainless pickling cheaper?
Citric passivation is the lower-cost finish ($ against $ for Stainless pickling) among the finishes FabDigit quotes. Both are priced per part with a lot minimum; the exact figure appears on the instant quote once the part is uploaded.