Product Categories / Metal Treatment / Steel Treatment / Iron Phosphating

Duraphos 503

Product description

  • Duraphos 503 is a synthesized liquid blend of inorganic phosphate, and special surfactant suitable to use at a low temperature and concentration for spray processes.


  • Duraphos 503 develops fine, smooth, and uniform bluish color amorphous on steel surface for durable bonding with final finish.
  • Duraphos 503 operates at low temperature, concentration and gives long life to final finish on metal surfaces.


  • Duraphos.503 can treat substrates like Iron, Steel, Zinc and Aluminuim.
  • Duraphos.503 Cleans, Degreases & Iron Phosphate the substrates.

Physical & Chemical Properties:

Appearance: Liquid
Color: Colorless Clear
pH (1%) at 25 °C : 2.9 ± 0.2 at 25 °C
Total Acid Points (1%) : 4.7 ± 0.3
Miscibility in water : Miscible


All required process tanks could be fabricated from
stainless steel. In Spray system Pump’s impeller &
spray nozzles must be of PP, PVC, or Stainless
Steel, use of any titanium or titanium alloys parts to
be avoided.

Operating Parameters:

Concentration (w/v%) : 1 to 2.0
Pointage (TAP) : 4 to 9
Temperature (°­C) : 45 to 50
Time (min) : 1 to 3
Nozzle pressure (Bar) : 1 to 1.5
pH : 3.0 to 4.5

Process Sequences:

  • Degreasing & Phosphating with Duraphos 503
  • Rinse with fresh water
  • Passivation
  • Drying

Initial Preparation :

  • Add 10 to 20 liter of Duraphos 503 per 1000 liters of operating volume.
  • Add 0.5 to 1.0 liter of Duradd 11 product in case of heavy oily steel to enhance cleaning.


Following precautions will help to maintain a clean operating bath.

  • Skim the oil from the surface of Duraphos 503 tank at least twice in a shift.
  • Clean the tank at least once in two months to remove all the deposited silt and dust in the bottom.
  • PH of the rinsing tanks should be kept between 6.5 to 8.5 for better cleaning and to keep work piece free from yellow patches.
  • In spray system nozzles should be cleaned time to time.