Differences phosphating and blackening

27 Mar.,2025

Blackening treatment: Blackening treatment produces a black oxide layer mainly by reacting with chemical reactants. It is mainly carried out using sodium hydroxide and sodium nitrite at 135-145 degrees Celsius and is more alkaline.

 

Author: Anna

 

Differences between phosphating and blackening

 

Process Differences

 

1. Top Waterjet Cutting Machine Cutter Head Assembly: Blackening treatment produces a black oxide layer mainly by reacting with chemical reactants. It is mainly carried out using sodium hydroxide and sodium nitrite at 135-145 degrees Celsius and is more alkaline.

 

2. Phosphating treatment: Phosphating treatment, on the other hand, involves placing the metal workpiece into a phosphate solution to form a phosphate cover layer through a chemical reaction. The main components include phosphoric acid and primary salts such as zinc, calcium, manganese, etc., and the treatment temperature ranges from 5-95 degrees.

 

Differences in corrosion resistance

 

1. Blackening treatment: the oxide layer formed by blackening treatment has poor corrosion resistance and is prone to rusting.

 

2. Phosphating treatment: the phosphate protective layer formed by phosphating treatment has better corrosion resistance, especially after applying rust preventive oil, its corrosion resistance is 10-20 times higher than that of blackening treatment.

 

Application Scenario Differences

 

1. Blackening treatment: mainly used for occasions with requirements on surface color, such as high-grade furniture, toys, stationery, watches and so on.

 

2. Phosphating treatment: It is applicable to the occasions with high requirements for corrosion resistance, hardness and abrasion resistance, such as automobiles, motorcycles, transmission parts and so on.