
BLACKENING CHEMICAL FOR METAL
1. Cold Blackening:
- Chemicals Used: Typically involve a mixture of copper selenide or copper sulfate solutions.
- Process:
. Clean the metal surface thoroughly to remove any oils, rust, or other contaminants.
. Immerse the metal in the cold blackening solution for a specified period.
. Rinse the metal with water and dry.
. Apply a sealant or oil to enhance corrosion resistance and deepen the black color.
. Applications: Suitable for small parts, tools, and hardware where a quick and relatively simple process is desired.
2. Hot Blackening:
- Chemicals Used: Involves the use of caustic soda (sodium hydroxide), nitrates, and nitrites in a heated bath.
- Process:
. Clean the metal surface to remove contaminants.
. Immerse the metal in a series of heated baths, including cleaning, blackening, and sealing baths.
. The blackening bath typically operates at temperatures around 140-150°C (284-302°F).
. Rinse and seal the metal to complete the process.
. Applications: Commonly used in industrial settings for parts like fasteners, automotive components, and firearms due to the durable and uniform finish it provides.
Keywords
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oils
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water
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mixture
nitrates
nitrites
cleaning
140-150°
hardware
firearms
fasteners
Chemicals
small parts
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heated bath
temperatures
Applications
caustic soda
metal surface
sealing baths
uniform finish
simple process
Hot Blackening
copper selenide
blackening bath
sodium hydroxide
other contaminants
BLACKENING CHEMICAL
industrial settings
corrosion resistance
automotive components
cold blackening solution
copper sulfate solutions