It is used for corrosion resistance, lubrication.

Hetal N. Fitter

Phosphating use to obtain an insulating layer on transformer, rotor, stator plates. The hardness of the phosphate film is lower than steel, but slightly exceeds the hardness of copper. It is fragile, unstable against frictional wear, does not affect the mechanical and electromagnetic properties of the metal. Due to the significant porosity, phosphate films retain oils, greases, varnishes well. Phosphate coatings are not wetted by molten metal, and this property is used in metallurgical production technology. A layer of phosphates, impregnated with lubricants, favorably affects the processes of wire drawing, pipe drawing, stamping.

Dear Dr. Hetal N. Fitter,

phosphate coating is the crystalline coating applied on the ferrous metals to inhibit corrosion. The phosphate coating lends a gray to black appearance of the surface. In many applications phosphate coating is followed by oil coating (P & O) to improve its rusting and anti-galling properties. In this post, we will introduce you to different types of phosphate coating, their industrial applications, and benefits.

Phosphate coatings are also utilized in the following industries:

-Hydraulic system manufacturers

-Cold-forming industries

-Heavy equipment manufacturers

-Gear & bearing manufacturers

-Electrical connector manufacturers

-Military armament suppliers

-Nuclear component fabricators

For more details, please see the source at: https://ws2coating.com/2017/07/12/a-beginners-guide-to-phosphate-coating/

Best regards, Pierluigi Traverso

Dear Hetal N. Fitter;

The Phosphate conversion coatings are an integral part of most finishing operations, serving one or more of the following functions: increase corrosion resistance, absorb lubricants, enhance appearance, promote adhesion, and provide wear resistance or facilitate cold formation.

in this coating, the surface of the basis metal transferred into a non-metallic crystalline coating. The reaction occurs in an acidic solution containing phosphate ions.

this coating used in many application depending on its type;

1- Heavy zinc phosphate is usually chosen for its ability to retain rust preventive oils and waxes.

2- Calcium-modified zinc phosphate is typically used as a base for paint or other organic coatings.

3- Cold-forming zinc phosphates are used to facilitate drawing, cold heading, stamping, or extruding of the basis metal.

4- Cold-forming zinc phosphates are used to facilitate drawing, cold heading, stamping, or extruding of the basis metal.

5- Iron phosphate is used as a base for paint or powder coat to enhance adhesion.

for more details can pass through

https://www.pfonline.com/articles/phosphate-conversion-coatings

It does help to improve corrosion resistance. It marginally improves appearance and finish. It does help in adhesion and slight improvement of wear properties.

It is used for corrosion resistance, lubrication.

Dear Hetal N. Fitter,

The information you found is correct.

Indeed, the phosphor coating is called upon to prevent corrosion of steels. In addition, steels are often reacted with oxygen and oxidized to give various oxides:

• FeO: iron(II) oxide, wüstite
• FeO2:[2] iron dioxide

• Mixed oxides of FeII and FeIII
  • Fe3O4: Iron(II,III) oxide, magnetite
  • Fe4O5[3]
  • Fe5O6[4]
  • Fe5O7[5]
  • Fe25O32[5]
  • Fe13O19[6]
• Oxide of FeIII
  • Fe2O3: iron(III) oxide
    • α-Fe2O3: alpha phase, hematite
    • β-Fe2O3: beta phase
    • γ-Fe2O3: gamma phase, maghemite
    • ε-Fe2O3: epsilon phase

They are most often removed chemically or mechanically. In dry cleaning, acids are used in which iron oxides are dissolved. To stop and prevent oxidation and use a method of coating with phosphate or lime coatings. Naturally, phosphate coatings are more expensive and durable. Phosphor coating is often not strongly associated with any decorative paints. Therefore, it is removed and primers are applied in its place, which bind well to the decorative paint.

In some areas of mechanical engineering, the phosphate coating is not removed to obtain rolled products. It is used to reduce friction between the tools and the deforming material. An example of this is when downloading soman to obtain wires or various widow profiles.

Newly, the phosphate coating removes the protection and worsens the strength of most paint coatings.

Dear Hetal,

This coating is formed by dipping the pickled workpiece surface in an aqueous solution of phosphorous acid and primary metal phosphates, especially zinc phosphate. This is generally applied by immersion or spraying phosphate coatings are made up of thin crystalline layers of phosphate compounds that adhere to the surface of the metal substrate. Phosphate conversion coatings are more popular.

Uses in commercial industry

Corrosion protection agents (providing unbeatable corrosion, rust proofing), anti-galling agents, and as a lubricant. These coatings are applied by immersion to bearings, bushings, fasteners and other common industrial products. Application in automotive engines and transmission systems, medical implants, bioactive glass coating, are more common.

Common types of phosphate conversion coatings

(1)Manganese phosphate coatings are used for reducing wear and for improvement in the running-in of a gearbox. In the phosphating process, phosphoric acid pickles the surface and forms with Mn-ions a layer of phosphate crystals with high oil affinity.

Metal Coatings offers black manganese phosphate coatings and dark gray manganese phosphate coatings (Type M) used for corrosion protection, anti-galling and lubricity. There is numerous phosphate coating available, manganese phosphate coatings are the hardest among them, it provides unbeatable corrosion and abrasion protection. In comparison to zinc phosphate coatings, manganese phosphate coatings offer continued wear protection after the breaking in of components that are subject to wearing. These coatings are applied only by immersion. Uses for manganese phosphate applications include the production of bearings, bushings, fasteners, and other common industrial products. Manganese phosphate coating is especially useful in projects that require sliding of parts, such as automotive engines and transmission systems.

(2) Calcium phosphate coatings for metallic implants in an attempt to improve their biointegration. The mineral constituent of vertebrate skeletal systems is principally composed of hydroxyapatite (HA; chemical formula Ca10(PO4)6(OH)2), which is one of the most well-known and widely studied biocompatible materials, and is used as an implantable ceramic due to its chemical and structural similarity with human hard tissue (50% mass, 70% volume)

(3) Calcium phosphate coatings, many techniques can be used to obtain ceramic coatings on metallic substrates, including PLD, PVD, CVD, plasma spray, etc. Taking advantage of sol–gel technology, bioactive glass coatings can be obtained by dip coating.

(4) Zinc phosphate coatings (Type Z) are also available and are mainly used for rust proofing on ferrous metals. They can be applied by immersion or spraying. Zinc phosphate is a lighter alternative to manganese phosphate, while providing resistance to harsh elements that tend to wear products quickly.

Ashish