Passivation Process: Precision Protection for Corrosion Resistance

Passivation is a chemical surface treatment process that enhances the corrosion resistance of stainless steels and other corrosion-resistant alloys. By removing free iron and other contaminants from the surface, passivation promotes the formation of a uniform, inert oxide layer that protects the underlying metal. This process is widely used in industries such as medical device manufacturing, aerospace, food processing, and semiconductor production — where cleanliness, corrosion protection, and regulatory compliance are critical.

The Passivation Process: Key Steps

Cleaning and Preparation: The metal surface is thoroughly cleaned to remove oils, greases, and particulates that could interfere with passivation.
Acid Bath Treatment: The clean surface is immersed in a nitric or citric acid solution, which removes free iron and enhances the formation of a passive oxide layer.
Rinsing and Drying: After treatment, the part is rinsed — typically with deionized water — and dried to prevent recontamination.

Common Passivation Specifications

AQUASGROUP systems are designed to support compliance with key industry standards such as ASTM A967, ASTM A380, AMS 2700, and others required for mission-critical applications.

Types of Passivation

Nitric Acid Passivation: A traditional method used for its aggressive action and compatibility with a wide range of stainless steel grades.
Citric Acid Passivation: A safer, environmentally friendly alternative ideal for sensitive applications like medical or food-grade components.

The Importance of Water Quality in Passivation

Water purity is vital throughout the passivation process — from rinsing to final cleaning — to prevent contamination and ensure a uniform, defect-free passive layer.

Deionized (DI) Water Rinse: Ensures optimal cleanliness and removes residual acid without introducing contaminants.
Closed-Loop Water Recycling: Reduces water use, improves consistency, and supports sustainability and compliance goals.

The Importance of Process Control in Passivation

Tight control over chemistry, temperature, dwell time, and rinse quality is essential for repeatable, high-performance results.

Consistency: Maintains uniform corrosion resistance and surface appearance across batches.
Quality: Helps meet stringent cleanliness and durability standards for critical components.
Efficiency: Reduces chemical use, waste generation, and overall cost per part.

The Role of Equipment Design in Passivation

AQUASGROUP’s passivation systems are engineered for precision and reliability, ensuring your parts meet the highest standards of quality and compliance.

Automated Chemistry Control: Maintains accurate acid concentrations and pH levels for consistent treatment.
Effective Agitation: Improves chemical contact and ensures even treatment across complex geometries.
Water Quality Integration: Includes DI water supply, rinsing stations, and recycling loops for optimal purity and efficiency.
Custom System Design: Tailored to your part sizes, throughput needs, and industry specifications.

Delivering Precision, Cleanliness, and Corrosion Resistance with Confidence

Since 1986, AQUASGROUP has been designing and building advanced metal finishing and water management systems trusted by major manufacturers worldwide. With thousands of proven installations, we provide solutions that integrate precise process control, water management, and durable equipment design — ensuring consistent, compliant, and cost-effective results.