Passiphos – 683 is a chromium free, inorganic, liquid chemical used in either immersion or spray final rinse, for zinc, manganese or iron phosphate coatings, to improve paint adhesion, and to minimize corrosion and blistering.
PHYSICAL AND CHEMICAL PROPERTIES
|Boiling Point Range||:||>100oC|
|Melting Point Range||:||0oC|
|Flash Point||:||Not Applicable|
|Specific Gravity (gr/cm3)||:||1.20 at 150C|
BUILD UP, CONTROL AND REPLENISHING:
Fill up the tank with DM water upto the operating level and start heating to maximum of 55 deg C. Add Passiphos – 683 at the rate of 250 to 500ml for every 100 litres of the bath so that bath acquires. a) a pH of 4 to 4.5 and/or b) an acid pointage (concentration) of 4-6. If necessary (if the pH of the bath becomes below 4.0), while mixing the bath thoroughly, repeating the addition, until the target pH of 4.0-4.5 is achieved.
These parameters (pH and Total acid pointage), are established, maintained and controlled as follows:
a) pH of the bath: Check the pH of the bath by means of a pH meter or pH paper(narrow range) A fresh bath prepared as above will have pH between 4 and 4.5. and also it has to be maintained through out between 4 and 4.5.
If at any point of time, the pH is less than 4.0 (due to acidic carry over from preceding rinse bath), then add Rxsol Passivation Liquid at the rate of 50 ml per 100 litres at a time, while mixing the bath thoroughly, repeat the addition, until the target pH of 4.0-4.5 is achieved.
If the pH goes beyond 4.5, then Passiphos – 683 is added at the rate of 500ml for every 1000 lit at a time, while mixing the bath thoroughly, repeat the addition, until the target pH of 4.0-4.5 is achieved. At any point of time, pH should never be allowed to exceed above 5.0 or depleted below 3.5.
Total Acid pointage: (concentration):
Total Acid pointage: (concentration): has to be determined by simple titration. as below
- Transfer 100 ml of Passivation bath solution to a 250 ml conical flask.
- Add 4 – 6 drops of phenolphthalein indicator solution.
- Titrate with 0.1 N sodium hydroxide solution until a permanent pink colour is reached.
The number of mls of alkali added is the total acid titration. This should be 4-6 and also has to be maintained in the range of 4 to 6 mls.
If at any point of time, the pointage is less than 4 (due to acidic carry over from preceding rinse bath), then add Rxsol Passivation Liquid at the rate of 50 ml per every 100 litres of bath size, at a time,while mixing the bath thoroughly, repeat the addition, until the target pointage of 4-6 is achieved.
If the pointage is above 6.0, then Passiphos – 683 is added at the rate of 500ml for every 1000 lit at a time, while mixing the bath thoroughly, repeat the addition, until the target pointage of 4-6 is achieved. (Normally, about 0.5 to 1.0 litre of Passiphos – 683 per 1000 litres bath of Passiphos – 683 will be needed for increasing pointage by 1 unit)
Drying: Drying is recommended prior to painting with all types of paint except those applied by electro deposition. In electro painting processes, drying is optional if deionised water rinsing has been used and is recommended if deionised water rinsing has been omitted.
Effluent: Passiphos – 683 solution may need treatment, neutralization or dilution before being discharged to the sewage.
Equipment: It is recommended that all tanks for use with this treatment constructed of stainless S.S.316 , FRP or rubber lined MS tanks.
Storage: Passiphos – 683 concentrate should be stored in a cool, dry place, protected from frost, direct sunlight and away from foodstuffs.
The details given in this data sheet reflect our current technical knowledge and experience, and are not a legally binding assurance of characteristics or suitability for a specific purpose.
Note: This article uses material from the http://rxmarine.com/