Citric Acid Passivation (ASTM A967 / AMS 2700)

Citric acid passivation removes free iron and restores the protective chromium-oxide layer on stainless steel — with a safer, lower-temperature, more environmentally responsible chemistry that many medical and aerospace OEMs now specify. Gleco passivates to ASTM A967 and AMS 2700 at our AS9100D and ISO 9001:2015 certified Texas plants.

AS9100D

ISO 9001:2015

ITAR Registered

Rowlett & McAllen, TX

📍 Available at: Rowlett, TX (Dallas–Fort Worth) only

Citric Passivation Specifications

Governing specs	ASTM A967; AMS 2700 (Method 2, citric); ASTM A380; QQ-P-35 (historical)
Citric methods (A967)	Citric 1–5 (varying concentration, temperature, and time)
Acceptance tests	Water immersion, high humidity, salt spray, copper sulfate, free-iron (potassium ferricyanide-nitric)
Dimensional impact	None (no coating is applied)
RoHS / environmental	Citric avoids dichromate entirely — the greener passivation route
Typical uses	Medical devices/instruments, aerospace and food hardware, post-machining cleanup

See also: passivation overview, citric passivation, nitric passivation.

Citric Passivation FAQ

What is passivation, and what does citric passivation do?

Passivation is a chemical treatment — not a coating — that removes free iron from a stainless surface and enhances the native chromium-oxide layer, restoring the corrosion resistance the alloy was designed to deliver. Citric passivation does this with a safer, more environmentally responsible chemistry.

Citric or nitric — which should I specify?

Both meet ASTM A967 and AMS 2700 when the correct method is called out. Citric is increasingly preferred for safety and environmental reasons and works well on most 300 and 400 series and PH stainless grades; nitric remains available where a legacy drawing requires it.

What stainless alloys suit citric passivation?

Citric handles most austenitic (300 series), many martensitic (400 series), and precipitation-hardening grades. For free-machining or high-carbon grades we confirm the correct method so the bath does not attack the alloy.

How do you verify passivation?

We verify per the practice specified on your drawing — water immersion, high humidity, salt spray, copper sulfate, or free-iron testing per ASTM A967 or AMS 2700 — supported by our on-site laboratories and documented in your certification package.

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Citric Acid Passivation (ASTM A967 / AMS 2700)

Citric Passivation Specifications

Citric Passivation FAQ

What is passivation, and what does citric passivation do?

Citric or nitric — which should I specify?

What stainless alloys suit citric passivation?

How do you verify passivation?

Get a Quote

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