Aluminium and aluminium alloys are
treated by a corrosion resistant conversion coating that is called
"CHROMATE COATING" or "CHROMATING".
Chromate conversion coatings are
commonly applied to everyday items such as hardware and tools, and can usually
be recognized by their distinctively iridescent, greenish-yellow color. Chromated means treated with a solution of chromate, usually hexavalent (valence +6) or
trivalent (valence +3), as a corrosion-fighting passivation layer--usually
applied to zinc and cadmium plated parts, or to aluminum.
Our Product : - Diachrome AL-51C (Cr6+),
packaging : 20Kg/can.
- Diafos 7000 (Cr3+), packaging :
20Kg/can.
A. Chromating hexavalent (Cr6+) :
Diachrome AL-51C is a
liquid compound designed to produce a transparent protective coating on
aluminium or aluminium alloys. The coating colour ranges from colourless to
slight iridescent, provides protection for aluminium and is an excellent
support for clear organic coatings. Diachrome AL-51C should be used when the
characteristic aluminium appearance and colour must be retained. Diachrome
AL-51C can be used both by spray and immersion.
Operating
Condition :
Cr(VI)-points 6.5 – 10.5
pH 2
to 2,8
Temperature 25 - 60 °C
Time (immersion) 2 to 4 min.
Time (spray) 30 to 120 sec.
Pressure 0 - 1.0
bar
Packaging
: 20Kg/Can
Control Cr(VI)-points with titration:
1. Pipette 50 ml sample of the Diachrome AL-51C bath into a 250 ml flask and dilute with 50 ml distilled water.
2. Add 25 ml of 10 % H2SO4 and 20 ml of 10% solution KJ.
3. Titrate with 0.1 N sodium thiosulphate solution (0,1N Na2S203) until the colour changes from brown to clear yellow.
4. Add several ml of the starch solution to the sample and continue the titration until the blue-black colour disappears.
5. Record the number of ml of 0.1 N sodium thiosulphate solution used as Cr(VI)-points.
A simple process of chromating (Cr6+) :
a. Degreasing
Product : Diaclean M-200 or Diaclean H-460
Temperature : Room Temperature (RT), Ambien
Contact Time : 5 - 15 Minutes (depending on the oil)
Concentration : 3 - 5%
b. Water
Rinsing
Product : City water
Temperature : Room Temperature (RT), Ambien
Contact Time : 1 - 2 Minutes
c. Chromating
Product : Diachrome Al-51C
Temperature : Room Temperature (RT), Ambien
Contact Time : 2 - 5 Minutes
Concentration : 3 - 5%
d. Water
Rinsing
Product : City water
Temperature : Room Temperature (RT), Ambien
Contact Time : 1 - 2 Minutes
e. Drying
The result after treatment with Chromating :
Yellow coating after treatment with chromating
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B. Chromating trivalent (Cr3+)
DIAFOS 7000 is a conversion coating process for aluminium.
Diafos 7000 gives
particularly good results for aluminium.
A
simple process of chromating (Cr3+) :
a. Degreasing
Product : Diaclean M-200 or Diaclean H-460
Temperature : Room Temperature (RT), Ambien
Contact Time : 2 - 5 Minutes (depending on the oil)
Concentration : 3 - 5%
b. Water
Rinsing
Product : City water
Temperature : Room Temperature (RT), Ambien
Contact Time : 1 - 2 Minutes
c. Conversion
coating (for the best result can be involve with etching)
Product : Diafos 7000 AA + DIAFOS 7000 AB
Temperature : Room Temperature (RT) - 55°C
Contact Time : 2 - 5 Minutes
Concentration : 4 - 5%
pH : 3.5 - 4.0
pH : 3.5 - 4.0
d. Water Rinsing
Product : City water
Temperature : Room Temperature (RT), Ambien
Contact Time : 1 - 2 Minutes
e. Drying.
Transaparnt coating after treatment with chromating tri valent (Cr3+)
For more details, please contact us :
PT. Aalen Chemicals Indonesia
Jl Pulobuaran III Blok G3,
Kawasan JIEP Pulogadung
Tlp : 021-46830522
Website : www.aalen.co.id
Email : aalen.chemicals@gmail.com, aalen@cbn.net.id
Website : www.aalen.co.id
Email : aalen.chemicals@gmail.com, aalen@cbn.net.id
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