Also under these conditions en layers must  be  resistant.

 

P-rich layers are chemically more resistant than P-poorer layers. A cause for this is the phosphorus content and the different structure of the deposited layers. 

 

 

Standards for the resistance and demand:

  • DIN 50966, now DIN EN ISO 4527 electroless nickel - coats

  • DIN 50017, sweat water test

  • DIN 50018, condensation water change climatic conditions with SO2-atmosphaere, " Kesternichtest "

  • DIN 50021, neutrally salt spray test and/or acetic acid salt spray test

  • RAL-RG 660, part 2 and 3

Electroless nickel - chemical resistance of deposited layers

 

The chemical resistance is the resistance of a sufficiently thick, nonporous en coat in a usually liquid medium. It is independent of the ground material but nevertheless of the surfaces geometry.

For this characteristic exists very much information - different medium contacts with the erosion rate in Ám/year.    

Chemical resistance of Ni-P-layers are dependent of :

  • the bath type

  • the deposition conditions

  • the phosphorus content in the layer

  • the contaminations in the electrolytes

  • the structure of the deposited layers

By corrosion resistance is to be understood the resistance of Ni-P-layers with layer thicknesses from few micrometers on a ground material in atmosphere or noxious gases and/or their mixtures. In contrast to the chemical resistance play here potential differences between ground material and coat an important role.

               

               

           

 

back              to the main page