Under the heading “wet processes”, CITRA intends to gather the broad family of electrolytic and chemical processes by applying conductive liquids. Indeed, it is necessary to distinguish: the “metallic deposits” which may require an electrolysis current to create one or severals layers of the substrate, and the chemical or electrolytic “conversions”, where the metallurgy of the substrat has a direct influence on the composition of the layer.

Custom development

Each of these modes can be easily done and adapted to the demand on the 25 tanks of CITRA’s pilot plant, with tank volumes between 50 and 250 L.

With the flexibility of this pilot plant, any development request can be considered, either in term of adapted formulations or in the form of custom commercial solutions which can tested on test samples and prototypes.

Metal Deposits

This process is used to produce metal coatings (Ni, Zn, Cu, Co, Cr …), alloys (Ni-P, Ni-W, Zn-Ni, Cu-Sn-Zn …) and ceramic-metal composites (Ni-SiC …). The thicknesses of these coatings are generally between 2 and 100 μm, on often complex substrate geometries. Covering large industrial areas, the applications are very varied and often tailored (hardness, wear, anti-corrosion).

 

CITRA offers a wide range of coatings and treatments (non-exhaustive list):

 

  • Copper plating on all materials
  • Micro / nanometric Nickel based composites
  • Matrix / particles composites
  • Adapted formulations (Ni-W, noble metals)

 

 


Conversion treatments

Mainly dedicated to light alloys (Al, Ti, Mg), anodizing is the common denomination of electrolytic conversions. In order to provide electrical insulation, low-friction, bacterial resistance or make easier to apply adhesives and varnish, these methods use formulations with increasingly complex additives, for new features.

CITRA offers a wide range of coatings and treatments (non-exhaustive list):

 

  • Colorful hard anodizing
  • Thick colorful anodizing
  • Titanium anodizing
  • Anodizing formulation (SAO, STA, HAO, CAO …)

 

Processes Deposit Conversion
Température range (°C) 20 à 90 -5 à 40
Current density (A/dm²) 0,1 à 30 0,1 à 3
Thickness (µm) 1 à 200 0,1 à 120
Coating’s homogeneity +/- 20% +/- 5%
Deposition speed (µm/h) 10 à 100  15 à 50

Metal Deposits

The most known electroless coating remains electroless nickel. Providing good anticorrosive properties (500 h BS) and a high hardness (900 HV), it allows a regular thickness, with a deposition speed of the order of 20 μm/h.

 

CITRA offers a wide range of coatings and treatments (non-exhaustive list):

 

  • Electroless Nickel and Copper coatings
  • Wood’s Nickel

 

 


Chemical conversion treatments

Generally applied for pre-painting preparations, chemical conversions of the type of chromatising or phosphatation make it possible to superficially oxidize the surfaces, in the form of complex combination layers, but of limited thickness.

CITRA offers a wide range of coatings and treatments (non-exhaustive list):

 

  • Chromatising
  • Phosphattation
  • Zincate without cyanide 
Processes Deposit (NiP) Conversion
Température range (°C) 88 Ambient
Current density (A/dm²)
Thickness (µm) 1 to 20 0,1 to 2
Coating’s homogeneity +/- 5% +/- 5%
Deposition’s speed (µm/h) 10 to 25 less than 1µm/min