Aquus® Thin Layer Technologies are conversion coatings, essentially consisting of inorganic oxides of zirconium, and or titanium. They are used to prepare metals for subsequent painting or powder coating, promoting adhesion and corrosion resistance of the fully finished articles.
Chromium trioxide and related chromium salts are environmentally persistent carcinogenic chemicals which are now under phase out in Europe. These salts have been used in various formulations for the treatment of Aluminium surfaces to prevent corrosion in demanding environments and as pretreatment prior to painting. In the search for chromate free pretreatment processes, the solution is to replace the chromium salts by others that might have the same properties, but will not be carcinogenic and be safer for operators and the environment.
The choices are restricted but products based on titanium and zirconium salts produce processes using the same reaction as chromating. The nanometer thick conversion coatings formed, with both elements are much thinner and more flexible than a chromate layer, but give excellent adhesion to any paint or powder coating and give similar results in artificial corrosion tests. The coatings are formed on aluminium as well as mild and galvanised steel.
Aquus TLT products offer a combination of benefits:
|Better performance than iron phosphate in salt spray||Less space needed for process equipment|
|Improved adhesion for paint and powder coatings||Low temperature operations needs less energy|
|Increased throughput with shorter contact times||More production with shorter process cycles|
|Low skilled simple operation|
|Environmental||Reduced chemical useage|
|No phosphates in rinse waters||Less sludge reduces maintenance|
|Low energy useage reduces CO2 for fossil fuels|
|Less rinse water wasteage|
All Aquus® Thin Layer Technology products conform to BS EN ISO 9717 2013
Cleaning And Conversion Coating Rinsing Drying
These innovative formulations were developed into practical processes to replace zinc and iron phosphate on steel in a cost effective and environmentally friendly process evolving to produce a new generation of Thin Layer Processes, where the conversion coating is produced during the degreasing stage in a single step. The process, that originally could only be used in zinc phosphating plants, was now usable in any iron phosphate installation with savings in space, energy and water usage using a simple process flow needing only three tanks:
The processes collectively are now referred to as Aquus TLT Thin Layer Technology®.
The Aquus® Thin Layer Process consists of one component for both bath make-up and replenishing. A pH adjustment component is needed when commissioning the bath, but the usage is so low that it can be neglected in the cost comparison. Because the process uses a much lower concentration than a liquid zinc or iron phosphate process and consumption during the process is very low, the production costs are lower in spite of a higher price for the Aquus® product range.
Sludge produced using the new low temperature process is approximately 5 times less than conventional phosphate processes, so the lifetime is longer and disposal costs are lower.
Another important advantage is the heat exchanger of the bath remains perfectly clean with the new process reducing energy costs. Like conventional processes the Thin Layer technology can be applied by immersion, static spray or in conveyorised tunnels.
Powder-coated or painted products tested for corrosion resistance in salt spray tests give results which are excellent on all substrates. The introduction of Aquus TLT Thin Layer Technology® reduces the costs of metal pre-treatment and improves corrosion resistance at the same time. Different substrates are treated in one process where the final quality of coated aluminium and galvanized steel is significantly better than with a conventional phosphating processes.
It is now possible to replace phosphating processes with the simpler and more efficient Aquus TLT ® as pre-treatment for powder coating, painting and cathodic electropainting.
|Aquus® ZI||0.8||35-50||Liquid||A single pack, high performance, high coating weight product, amorphous complex zirconium oxide coating, which inhibits corrosion and improves the adhesion of subsequently applied organic coatings. Coating weights are normally in the range 0.2-0.5g/m2
See Technical Data Sheet
A single pack, high performance, high coating weight product, converts the metal surface to an amorphous complex titanium/zirconium oxide coating, which inhibits corrosion and improves the adhesion of subsequently applied organic coatings. Coating weights are normally in the range 0.2-0.5g/m2
|Aquus® TI||0.8||35-50||Liquid||A single pack, high performance, high coating weight product, amorphous complex titanium oxide coating, which inhibits corrosion and improves the adhesion of subsequently applied organic coatings. Coating weights are normally in the range 0.2-0.5g/m2
See Technical Data Sheet
|Aquus® EQUIPMENT||List of suitable equipment.|