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  2. Information on Surface Technology
  3. Procedure


The NU-BLAK® SYSTEM allows the chemical blacking (oxydising) of iron components using a dipping method.

A sub-group is the blacking of the parts with brush-on cream. Especially suited for the treatment of small parts or spots under repair and refurbishing conditions.

The NU-BLAK® procedure is qualified to achieve a uniform fine-dark black surface and will increase by oiling/sealing the corrosion protection of materials like cast iron, alloyed and low-alloy steel, zinc and zinc pressure die cast without secondary treatment.

These are commonly found within the manufacturing industry. Producers of mass production components are using the chemical blacking process to reach a decorative character in an inexpensive way. Another important feature is that the finish does not result in an alteration to the dimension of the component. This is a special advantage against other kinds of corrosion protection coatings.The treatment works without hydrogen embrittlement and fulfils the requirements of DIN 50 938 easily.

Blacking at room temperature means the dipping of iron components in a mild, light chemically, non-polluting solution at about 20°C. The effect of the solution is a change of the surface structure. Treated surfaces will get a black coat of iron oxide.

Unlike the conventional blacking method at 145°C in connection with dangerous, toxic acids and solutions, the NU-BLAK® SYSTEM will work only at room temperature.

List of Applications

Industrial components Gauges and measuring instruments
Turn- and mill parts (also tolerances) Parts of cast iron and pressure die cast
Hydraulic components Hand tools
Printing machine parts Automotive, gears, etc.
Tool holders Joints and artificial jewellery
Geared components Springs, screws, standard parts
Tool- and die Shops Tools of all kind – also repair


Advantages of NU-BLAK® -blacking at room temperature compared to the conventional method

  • Immediately available – also for small quantities
  • No loss of time or transportation costs
  • No damage in transit of valuable precision components
  • No energy consumption - blacking at room temperature
  • No dimensional change
  • No red spots – no salt leach-outs
  • Safe and uniform fine-dark colouring is obtained over threads, blind holes etc.
  • High corrosion-proof by oiling / sealing
  • Wiping resistance coating 
  • Inexpensive chemicals from one source
  • Semi- and full automatic plants in different sizes
  • Nearly no waste disposal
  • No aggressive solutions – safety- and application data sheets available 
  • Operates economically
  • Simple reactivation of the bath by adding chemicals
  • Safe handling
  • No process control of plants, no ventilation and no specific rooms required
  • Low water consumption because of highly efficient filtration in a closed circuit 


Forget regarding of warnings and directions like:

  • Exact inspection of the temperature at 145°C
  • Delay of the boiling point
  • Material (larger parts too cold)
  • Dipping time of 10 - 20 minutes or longer
  • Nature and consistence of the chemicals
  • Concentration
  • Different baths
  • Dangerous adding of water
  • Protective clothing required
  • Extraction equipment etc. 


You ought to consider the high energy loss for the permanent run up of a conventional plant. The NU-BLAK® System works without energy consumption. You can interrupt and restart the process every time and even after long storage time the chemicals do not collapse!

We provide EU-Application data sheets for the safe and functional handling.