Phos Black #2



Phos Black #2 is a conditioning solution for incorporation into conventional zinc phosphate immersion systems to produce a matte black phosphate coating on steel parts.


Phos Black #2 is operated at ambient temperature, requires no accelerator and maintained by a minimum of chemical control.


EQUIPMENT: Phos Black #2 tanks should be constructed of fiberglass or rubber, PVC or Koroseal lined. 



Solution of Phos Black #2 is prepared as follows:

       Water                           87% by volume

       Phos Black # 2              13% by  volume


Phos Black #2 is designed for use in rack, basket, or barrel immersion systems.  To avoid marking parts, while processing in barrel or basket, revolve the equipment very slowly, about 1 rpm.



1.  Alkaline soak clean to remove oil and grease.

2.  Cold water rinse to remove all traces of alkali cleaner.

3.  Acid dip (25-50% hydrochloric acid) if necessary to remove rust or scale.

4.  Warm water rinse

5.  Phos Black #2 immersion time of 15 seconds to 3 minutes

6.  Cold water rinse

7.  Zinc Phosphate dip

8.  Cold water rinse



Once the bath is ready for use, record total acid and maintain at this operating level with additions of Phos Black #2.


1.  Pipette 2 mls sample into a 100 ml beaker

2.  Add 50 mls distilled water

3.  Add 3-5 drops of phenolphthalein indicator

4.  Titrate with 0.1N sodium hydroxide

5.  Maintain total acid at new solution level


If the work is not black enough, add 0.25% by volume increments of Phos Black #2 until the desired color is obtained - 1 quart per 100 gallons of zinc phosphate dip solution.


Read the Material Safety Data Sheet before using this product.



The information presented herein, while not guaranteed, is to the best of our knowledge true and accurate.  No warranty or guarantee expressed or implied is made regarding the performance of any products, since the manner of use is beyond our control.  No suggestion for product use or anything contained herein, shall be construed as a recommendation for its use in infringement of any existing patent and we assume no responsibility or liability for operations which do infringe any such patents.  The above includes confidential and proprietary information of So Clean Solutions and is furnished to you for your use solely on products or processes supplied by us to you.


Product Data Sheet\ PH007                                                     Effective Date 06-07-07                                          Supersedes 7-17-02