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Minghan Chemical
Passivation & Corrosion Resistance

Brass Passivation Before-and-after Comparison

For brass parts that easily darken, discolor and show uneven appearance after cleaning, Minghan established a degreasing, brass passivation and drying packaging process to improve surface cleanliness, oxidation resistance and storage stability.

2026-06-10 South China copper parts processing plant Brass parts / copper alloy hardware
Brass Passivation Before-and-after Comparison Before Brass Passivation
Brass Passivation Before-and-after Comparison After Brass Passivation

Case Overview

The customer’s brass hardware and copper alloy connectors were prone to surface oxidation, darkening, discoloration, fingerprints and local color variation during machining, cleaning, handling and short-term storage. Based on the high surface activity of copper-zinc alloy, appearance stability requirements and storage cycle, Minghan Chemical provided a degreasing and brass passivation anti-discoloration process to improve surface stability and appearance consistency.

Customer Challenge

Brass surfaces are sensitive to air, sweat, cleaning residue and humid environments. Without effective protection after cleaning, the surface may darken, discolor or develop localized oxidation spots within a short time. The customer needed better anti-discoloration performance during storage, packaging and pre-assembly while maintaining the natural brass appearance and metallic texture as much as possible.

Solution

Minghan recommended a process of degreasing, rinsing, brass passivation, final rinsing and drying packaging. Pretreatment removes machining oil, fingerprints and surface contaminants. The brass passivation agent forms an anti-oxidation protective film on the copper alloy surface, reducing discoloration risk during handling, packaging and transportation.

Result

After treatment, the brass surface became cleaner and more uniform, with visible improvement in dull oxidation, fingerprints and local discoloration. The brass passivation film improved short-term oxidation resistance and anti-discoloration performance, helping reduce storage discoloration, appearance rework and batch shipment risks.

Implementation Process

01

Sample review

Confirm brass material, oxidation level, oil contamination, appearance requirement and storage cycle.

02

Degreasing cleaning

Remove machining oil, fingerprints, dust and surface contamination before passivation.

03

Brass passivation

Match passivation concentration, treatment time and temperature to form an anti-oxidation protective film.

04

Rinsing control

Rinse thoroughly to reduce residue, water marks and localized uneven appearance.

05

Drying and packaging

Dry promptly and use clean packaging to reduce secondary contamination and short-term discoloration.

Case Information

Surface condition

Improved from dull oxidation, discoloration and fingerprint residues to a clean and uniform brass finish

Oxidation resistance

Brass passivation film improves short-term anti-discoloration and storage stability

Process compatibility

Suitable for brass hardware, copper alloy connectors, terminals and decorative copper parts

Delivery value

Reduces storage discoloration and appearance rework risk, improving batch shipment stability

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Brass Passivation Before-and-after Case Brief

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