ZINCHROMATE OLIVE GREEN 173 (S)
OLIVE GREEN CHROMATE CONVERSION PROCESS
THIS PROCESS IS SPECIALLY DESIGNED TO PRODUCE A HEAVY OLIVE GREEN CHROMATE CONVERSION COATING ON CYANIDE AS WELL AS CHLORIDE ZINC ELECTROPLATED PARTS. THE CHROMATED FILM PRODUCED BY THE PROCESS, AFFORD VERY HIGH CORROSION RESISTANCE OF OVER 16 HOURS IN SALT SPRAY TEST. THIS IS AN IDEAL PRODUCT FOR AIRCRAFT AND AUTOMOBILES PARTS, ELECTRICAL APPLIANCES AND DEFENCE APPLICATIONS WHERE HIGH CORROSION RESISTANCE IS REQUIRED.
THE PROCESS IS VERY CONVENIENT TO USE, HAVE LONG LIFE AND REQUIRE ONLY ROUTINE MAINTENANCE. IT CAN BE USED IN BOTH MANUAL AUTOMATIC RACK AND BASKET OPERATIONS AND MAY BE USED IN
BARREL OPERATIONS.
OPERATING CONDITIONS :
ZINCHROMATE OLIVE GREEN – 173 80 – 120 ML/LIT.
TEMPERATURE 25 – 40*C
PH (ELECTROMETRIC) 0.8-1.4
TIME 30 – 120 SECONDS
AGITATION COMPONENT MOVEMENT
OR AIR
EQUIPMENT :
PVC OR HDPE PLASTIC CONTAINERS ARE SUITABLE.
MAKE UP :
1. FILL THE CLEAN TANK WITH TWO THIRD FULL OF CLEAN WATER.
2. ADD REQUIRED QUANTITY ZINCHROMATE OLIVE GREEN-173 AND STIR
THE SOLUTION WELL.
3. FILL THE TANK TO OPERATING VOLUME AND STIR TO ENSURE
THROUGH MIXING OF THE OPERATING SOLUTION.
PROCESS SEQUENCE :
1. ZINC PLATING WITH MINIMUM 7 MICRON THICKNESS.
2. COLD WATER RINSE TWICE.
3. ZINCHROMATE OLIVE GREEN – 173 PROCESS DIP.
4. COLD WATER RINSE TWICE.
5. DRY.
MAINTENANCE :
REPLENISHMENT ADDITIONS OF ZINCHROMATE OLIVE GREEN-173 SOLUTION ARE EVIDENCED BY CHANGE IN COLOUR OF THE PROCESSED PARTS AND BY INCREASING IN PH OR BY LONGER IMMERSION TIME REQUIRED TO PRODUCE ACCEPTABLE COLOUR. REGULAR ADDITION OF 173 STOCK SOLUTION SHOULD BE MADE ON VISUAL OBSERVATION OF PARTS BEING PROCESSED, BY PH CONTROL OR BY SPELING ANALYTICAL MEASURES. NORMALLY 1 LITRE OF 173 CONCENTRATED SOLUTION CAN BE ABLE TO PRODUCED ACCEPTABLE COLOUR ON 120-150 SQ.FT. OF TREATED AREA OF PROCESSED PARTS. THIS CONSUMPTION MAY VERY ACCORDING TO THE TREATMENT TIME, SHAPE AND SIZE OF ARTICLES AND DRAG OUT LOSSES.
ANALYTICAL CONTROL :
5 ML PIPETTE
10 ML MEASURING CYLINDER
50 ML BURETTE
250 ML ERLENMEYER FLASK
0.1 N SODIUM THIO SULPHATE SOLUTION
25 % SULPHURIC ACID SOLUTION
10 % POTASSIUM IODIDE SOLUTION
1 % STARCH SOLUTION
SODIUM FLUORIDE
PROCEDURE :
PIPETTE 2.5 ML OF THE SOLUTION INTO A 250 ML ERLENMEYER FLASK. ADD 10 ML 25 % SULPHURIC ACID SOLUTION, 1.0 GM SODIUM FLUORIDE AND 15 ML OF 10 % POTASSIUM IODIDE SOLUTION. SWIRL AND KEEP IT IN DARK FOR 5 MINUTE. TITRATE WITH 0.1 N SODIUM THIOSULPHATE SOLUTION TO A LIGHT YELLOW COLOUR, ADD 2 ML OF 1 % STARCH SOLUTION AND CONTINUE THE TITRATION UNTIL A BLUE BLACK COLOUR DISAPPEARS.
CALCULATIONS :
_______ ML OF 0.1 N SODIUM THIOSULPHATE USED X 4.5 =____________
ML/LITRE OF 173.