Stainless Steel Passivation Services

Core Functional Advantages of Precision Passivation

• Dramatically Improved Corrosion Resistance: Up to 30 times better rust protection vs untreated stainless steel, prolong component service life in humid & chemical environments.
• Zero Dimensional Variation: Microscopic surface-only chemical reaction, no material removal to protect tight precision tolerance.
• Ultra-Clean Surface Property: Eliminate free iron contamination to reduce particle shedding, ideal for semiconductor vacuum & food sanitary applications.
• Excellent Biocompatibility: Citric passivated surface meets FDA & medical standard for surgical instruments and implant devices.
• Cost-Effective Post-Treatment: Lower maintenance cost and avoid premature component replacement in corrosive working condition.

Passivation Compatible Base Materials

• Austenitic Stainless: 304,316,316L mainstream food & medical grade material
• Martensitic Stainless: 410,420,440C tool & mold stainless
• Precipitation Hardening Stainless: 17-4PH,15-5PH aerospace high-strength alloy
• Duplex Stainless & Selected Nickel/Titanium Alloys for special corrosion-resistant parts

Passivation Standard Process

• Pre-Project DFM & Prep: Optimize processes; use bead blasting or electropolishing to remove heavy oxides.
• Degreasing & Cleaning: Eliminate oil and contaminants for consistent passivation results.
• Acid Bath Treatment: Apply matched acid solutions with controlled temperature and immersion time.
• DI Water Rinsing: Multiple rinses to remove residual acid and prevent surface stains.
• Drying & Quality Inspection: Dry parts thoroughly; conduct professional corrosion and cleanliness tests in-house.

One-stop Integrated Passivation Service Superiority

• Full vertical in-house chain: Raw material→CNC→pre-finish→passivation→packaging under single PO management.
• Flexible production: Small prototype trial batches to large-volume automated tank processing with adjustable lead time.
• Complete batch certification: COC conformity certificate, process record and full test report supplied per shipment.
• Custom combo service: Combine passivation + electropolishing/bead blasting to satisfy complex surface requirements.

Types of Passivation Processes

• Nitric Acid Passivation – Traditional method using nitric acid solutions (20–50% concentration), effective for most stainless steel grades and approved by ASTM A967 and QQ-P-35 standards.
• Citric Acid Passivation – Eco-friendly alternative with no hazardous fumes or heavy metal disposal issues. Provides superior performance on 400-series stainless and is preferred for medical and food-contact applications.
• Electrochemical Passivation – Uses anodic current to accelerate oxide layer formation, ideal for complex geometries and parts requiring maximum corrosion resistance.
• High-Temperature Passivation – Applied to heat-resistant alloys where standard acid baths are ineffective.

Passivation Quality Standards & Testing Methods

We certify passivation to these recognized specifications:

• ASTM A967 (current standard for chemical passivation treatments)
• ASTM F1089 (for surgical implant passivation)
• AMS 2700 (aerospace material specification)
• ISO 16048 (passivation of corrosion-resistant steel fasteners)

Verification tests performed in-house:

• Water Break Test – Confirms a clean, contamination-free surface.
• Copper Sulfate Test – Detects free iron on stainless steel.
• Ferroxyl Test – Identifies reactive iron residues.
• Humidity Chamber Exposure – Optional accelerated corrosion validation for critical parts.