Zinc Phosphate the chemical formula of zinc phosphate is Zn3(PO4)2
Properties: Pure zinc phosphate is the best substitute of conventional antirust pigments containing heavy metals such as lead and chrome.
Usage: Pure zinc phosphate is widely used in various coating materials for preparation of waterproof, acid-resistant or corrosion preventive coating materials such as phenolic paint, epoxy paint, acrylic paint, paste paint and water-soluble resin paint in the fields of shipbuilding, automobile, industrial machinery, light metal, household appliances and metal containers for foods.
The most commonly applied paint pretreatment for developing good bonding qualities between paint and the galvanized or galvannealed coatings on steel sheet is zinc phosphate. In addition to the excellent effect that a zinc phosphate coating has on paint adhesion, it also aids to decrease, often dramatically, the tendency for paint disbondment during subsequent atmospheric exposure in a corrosive environment. Zinc phosphate coatings can be applied to the galvanized sheet while it is in coil form by either the steel manufacturer or a coil coater (manufacturer of prepainted sheet), or it can be applied to the cut sheet or fabricated article by the end-use manufacturer. The usual zinc phosphate process involves several steps, both if the coating is applied on a coil line or by the part manufacturer. If there are oils present on the surface of the galvanized or galvannealed steel, the first step is the removal of the oil by degreasing. This might involve cleaning with the use of an aqueous, alkaline cleaning solution or by other forms of degreasing with the use of solvents. Preferably, if the phosphating is done on a coilprocessing line, the next step involves the use of a conditioning stage; the application of a titanium phosphate conditioner to prepare the galvanized/galvannealed surface for the development of a superior zinc phosphate coating. The titanium phosphate aids in the development of a uniform phosphate coating with small zinc phosphate crystals by depositing sub-micron size particles which act as seeds to promote the growth of zinc phosphate crystals on the surface of the galvanized sheet.
Applications of Zinc Phosphate Coatings:
Oil & Gas Industry: Primer for critical components
Defense: CARC primer. Non reflective finish for equipment.
Automotive: Base for organic coatings.
Aerospace: Break-in of moving parts and threads. Primer for specialized coatings.
Gears & Bearings: Holds lubricants on surface.
Zinc phosphate chemical examination report :
|Project||Guaranteed Values||Examination result|
|The PH Value||41401||6.5|
|Oil absorption g/100g||25-35||27|
|Residue on sieve( 45um)||0.005||0.4|