Surface Finishing

Passivation Services

Chemical treatment that removes free iron from stainless steel surfaces, allowing the passive chromium oxide layer to reform — restoring maximum corrosion resistance for medical, food-grade, and marine applications.

Process Overview

ASTM A967 Compliant

Nitric acid (Type II) and citric acid (Type VI) passivation methods. AMS 2700 for aerospace applications.

Medical & Food Grade

Essential for surgical instruments, implant components, and food processing equipment — ensures biocompatibility and hygiene.

All Stainless Grades

303, 304, 316, 316L, 17-4PH, 15-5PH, and duplex stainless steels. Certificate of conformance provided.

Specifications

ParameterSpecification
StandardASTM A967, AMS 2700
MethodsNitric acid (Type II), Citric acid (Type VI)
Suitable Alloys303, 304, 316, 316L, 17-4PH, 15-5PH, 2205
TestingCopper sulfate test, water immersion test
DocumentationCertificate of conformance per batch

Compatible Materials

  • Stainless 304 / 304L
  • Stainless 316 / 316L
  • 17-4PH
  • 15-5PH
  • Duplex 2205

Applications

  • Surgical instruments
  • Medical implant components
  • Food processing equipment
  • Marine hardware
  • Pharmaceutical fittings

Frequently Asked Questions

Why is passivation needed after machining?

CNC machining embeds free iron and tool steel particles on the surface, which rust and compromise corrosion resistance. Passivation removes these contaminants and restores the passive oxide layer.

Citric vs nitric acid passivation?

Citric acid (Type VI) is safer, more environmentally friendly, and increasingly preferred for medical devices. Nitric acid (Type II) is the traditional aerospace standard.

Does passivation change dimensions?

No — passivation removes a negligible amount of material (<0.25μm). No dimensional compensation needed.

Need Passivation on Your Parts?

Upload your drawings and specify your finishing requirements — we'll quote machining and finishing together within 24 hours.

Request a Quote