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Tartaric Sulphuric Anodising


The ultimate replacement for Chromic Acid Anodising

Poeton Apticote 300TSA – Tartaric Sulphuring Anodising –provides superb corrosion protection and paint bonding properties for a wide range of aluminium alloys. Apticote 300TSA is now becoming standard for the Aerospace and Defence industries, replacing the environmentally unacceptable Chromic Acid Anodising.

Adopted and specified by Airbus, the process has been installed by Poeton at their Cardiff plant, complying with AIPI 02-01-003 (Approved in June 2011) and BS EN 4704, supported by NDT and painting facilities. We can offer a TSA service to all our Aerospace and Defence customers, from initial non-destructive inspection, through pre-treatment, TSA processing, post-treatment and to final paint priming.

Poeton Apticote 300TSA is the first and the best, available now, with proven performance and compliance.


  • Total coverage
  • Excellent substrate/coating bond
  • Salt mist corrosion performance (ISO 9227) complies with AIPI 02-01-003
  • Smooth, aesthetically pleasing
  • Maximised paint adhesion (ISO 2409), complying with AIPI 02-01-003
  • A complete package with NDT and paint priming
  • Environmentally acceptable

Thickness and coverage

APTICOTE 300TSA provides a homogeneous anodised coating on aluminium with a minimum thickness of 2 microns and a maximum of 7 microns. It is evaluated by an eddy-current technique, in accordance with ISO 2360, and by the coating weight, in accordance with EN 12373-2.

Coverage of the part is evaluated by an ohmmeter - Galvo Test 2 using the insulating properties of the film.

Corrosion protection

Salt spray tests are performed in accordance with ISO 9227, using aluminium alloy 2024 T3, on a TSA hot-water sealed specimen (60 minutes at > 96°C) and on a TSA + post-treatment process specimen (that is the Alodine 1200 Chemical Conversion Process).




TSA + seal

96 hours

Zero pitting marks per dm²

TSA + post treatment

336 hours

Average of 1.7 pitting marks per dm². Max pit size 0.7mm


Just some of the APTICOTE 300TSA aluminium applications:

  • Launch rails
  • Actuators
  • Fuel pipes and connectors
  • Landing gear
  • Missile locks and ejectors
  • Underwater weapons

Generically, APTICOTE 300TSA on aluminium is used:

  • For electrical insulation
  • For protection under mildly corrosive conditions
  • As a surface key for paint application
  • When it is important to minimise fatigue loss
  • As an environmentally acceptable replacement for chromic acid anodising


APTICOTE 300TSA can be applied to all aluminium alloys, including those commonly used in aerospace and defence applications - 2124 (T3), 7175 and 6082.

Surface morphology

In comparison to Chromic Acid Anodised surfaces, APTICOTE 300TSA gives a slightly coarser grain structure, with additional surface porosity. It provides the optimum adhesion for subsequent paint priming without, crucially, compromising the corrosion protection.


APTICOTE 300TSA is applied to the AIPI 02-01-003 specification. Rotating bar tests have shown that the fatigue life of TSA treated aluminium alloy samples is identical to that produced after Chromic Acid Anodising.

Liquid Penetrant Inspection(LPI)

Non Destructive Testing

Poeton offer a comprehensive non-destructive testing service, including Liquid Penetrant Inspection (LPI). All parts are individually inspected for cracks, porosity, weld defects and any manufacturing or casting imperfections that might subsequent impair the TSA step.

(left) Liquid Penetrant Inspection (LPI)

Poeton Laboratory

Salt fog cabinet

Salt fog cabinet

We work to a strict Quality Plan, dictated by the customer Specification, overseen by our laboratory.

Our facilities include:

  • Optical Microscopy
  • Scanning Electron
  • Microscopy
  • Metallography
  • Chemical analysis
  • Atomic Absorption Technique
  • Corrosion testing
  • Adhesion testing
  • Wear testing

We are able to undertake all the required analysis for bath control, fully complying with the specifications. For instance, acid concentration (to AITM 3.0030) and dissolved aluminium (by Atomic Absorption).

Our processing capability

Our TSA processing line for aluminium is fully automated and computer controlled:

  • Sizes up to 0.5 metre and 20 kg
  • Automatic voltage ramping
  • Precisely controlled sequencing – pre-treatment, TSA, post-treatment
  • Bath temperature control to within 1°C
  • NDT capable of inspecting parts up to 1 metre long, and smaller parts at 50 per hour
  • Painting priming on parts up to 2 metres long and smaller parts in batches of 200
TSA Processing Facility

TSA Processing Facility


Poeton have a large paint application facility, environmentally controlled and using primers that are chromate free. We can process aluminium parts up to 2 metres long or 50 kg in weight, or batches of smaller parts up to 200 at a time.

When applied to APTICOTE 300TSA treated aluminium, the primer adhesion matches the performance specified in the ISO 2409 Crosscut Test.

Environmental aspects

Apart from observing the obvious precautions of working with strong acids, the two bath constituents are relatively non-hazardous, and none of the constituents meet the SVHC criteria of REACH legislation.

More info about anodising

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For details of all our processing capabilities, size and capacity, please follow this link.