Metal Surface Pretreatment Conversion Coating-

ZL-7 Nano Ceramic Conversion Coating

What is it?
The nano-ceramic phosphate-free conversion coating is a type of reactive pre-treatment agent by adopting zirconium salt as basic ingredient to replace the traditional phosphate containing liquid. Thanks to the special membrane-forming assistant agent added in the coating, it can create a conversion coating similar to the phosphating film shaping on the surface of steel, galvanized and aluminum plates or sheets. The conversion film is appeared as nano- Zr salt, the film-forming substances include ZrO2,Zr(OH)4,TiO2,Ti(OH)4 and SiO2. It is a combined coating with amorphous oxide composite and organic 3D network structure in ceramic property, it is also called “Nano-Ceramic Conversion Coating Technology” in the industry.

Based on outstanding quick filming, the generated conversion film features powerful corrosion resistance, enhanced adhesive force for the coating, it is the ideal pre-treatment agent for painting. The color change of the film is subject to the film weight, workpiece material and temperature, concentration of chemicals and processing duration. Generally, the film forming on the surface of workpiece is transformed from colorless to golden and finally blue. The phosphate-free conversion agent can be widely applicable for surface treatment of varied cold rolled steel sheets, galvanized sheets, aluminum based metal materials. It is free of phosphate, chromium or nickel, no accelerant required, dregs free. Operation under normal temperature, it is energy saving and environmentally friendly.

Reactive Mechanism
(the above diagram illustrates the reactive mechanism)

Main Features of ZL-7 Nano Ceramic Conversion Coating:
⊙ Direct & easy to use based on the current production line;
⊙ Short treatment duration (60-150s);
⊙ Environmentally friendly (no nickel, chrome, copper contained);
⊙ Dregs free;
⊙ No heating required
⊙ No surface conditioning and passivating required;
⊙ Multi-metals treatment, no restriction on aluminum percentage ;
⊙ Low consumption of water;
⊙ Low discharge & treatment of waster water;
⊙ Easy to use and maintain;

Environmentally Friendly

  1. The nano-ceramic conversion agent is free of heavy metals such as Zn, Ni, Mn and etc, reduced water consumption and waste water treatment remarkably;
  2. Workable in normal room temperature, free of phosphate, oxidation reductant, no emission of nitrogen oxides and exhaust; dreg free (dreg<0.1g/m2) ; the waste water treatment system can be closed off, recycled water in use, no waste water generated.

Easy Operation & Management  

  1. It is well known that the phosphating process will generate a mass of phosphating dregs, the production line must be shut down frequently in order to remove the massive dregs in the phosphating tanks, after removal the dregs, it should make necessary cleaning, which would be unavoidable to waste some phosphating agent. This is a troublesome and time-consuming process. No any such trouble anymore when used with nano-ceramic conversion agent.
  2. It is required to control the freeacid, total acid value, acid ratio, accelerating agent, temperature and other parameters; with nano-ceramic conversion agent, only PH and EDTA titration need to be controlled;
  3. No surface conditioning tank needed when processing with nano-ceramic conversion agent, thus saving the chemical consumption accordingly, making the operation more easily.

Cost Analysis

As the costs of energy sources such as zinc, nickel and phosphate have been kept rising constantly in recent years, the nano-ceramic conversion agent has increasingly highlighted its prevailing advantages on cost for the manufacturers.


Zinc Phosphate Coating

ZL-7 Phosphate-free Conversion Coating

Operating Temperature


Normal Temperature

Energy Consumption



Electricity Consumption



Water Consumption



Waste Water Treatment



The above values indicate the consumption index between the zinc phosphate agent and phosphate-free conversion agent used for processing same amount of metal sheets.

Note: the cost amount saved can be varied subject to different mills

Product Line Demonstration

Our ZL-7 phosphate-free conversion coating is being widely used by Midea, China.

Refrigerator/Freezer Coating Line
  (Midea, China)
S6002005.JPG   S6002020.JPG
Air-conditioner Coating Line
  (Midea, China)

ZL-7 nano ceramic conversion coatingThe technology of nano-ceramic conversion coating can make the coating process free of phosphate, Ni, Mn, Cr and other hazardous heavy metals, put the cancer-sensitive substances – nitrite to end, in addition, it can reduce energy consumption. As the ever-growing application and utility, the of nano-ceramic conversion technology can bring a revolutionary change to the metal surface treatment industry, and create more benefits to the manufacturers.

RoHS Compliance

Our ZL-7 nano-ceramic conversion coating is in compliance with RoHS.

SGS Report

video downloadFull SGS Report Download (222KB in PDF format) (members only)

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