AAF Anodic Bond
The ultimate in pretreatment
FOR ARCHITECTURAL POWDER COATINGs
Extending the Serviceable life of Architectural Powder Coatings
Aluminium “bioframe” struts Powder Coated in 2008 by AAF (Dandenong).
Powder Coating, Pretreatment, and Long-Term Durability
Back in 2008, AAF (Dandenong) powder-coated the aluminum “bioframe” struts for projects such as the AAMI Stadium in Melbourne using Interpon D2015 in Stadium White. At that time, the warranty offered was 20 years for film integrity and 15 years for colour retention.
By 2025, powder coating technology has advanced significantly, with systems like Interpon Gold Global now offering 25 years coverage for both film integrity and colour retention. This represents clear progress in coating performance and warranty assurance.
However, in the context of modern sustainability goals and the demands of the built environment, the actual service life expectation should go well beyond the warranty period—especially for major infrastructure projects.
A critical factor in achieving long-term durability is surface pretreatment. Historically, Chromate Chemical Conversion (CCC) systems delivered excellent protection. But with chromates now banned in Europe (from 2024) and Australian systems rapidly transitioning to non-chrome alternatives, performance outcomes have shifted. While non-chrome chemical conversion meet minimum standards, they have not consistently matched the long-term durability of CCC pretreatments.
The ultimate pretreatment system—and the only one now Highly Recommended Globally by Qualicoat International for architectural applications demanding exceptional longevity—is pre-anodised pretreatment.
In Australia, AAF’s ANODIC BOND pre-anodised technology now makes this world-leading pretreatment available, ensuring that both the coating system and the pretreatment align with the service life expectations of 25 years and beyond, supporting the sustainability and performance requirements of modern construction.
AAF ANODIC BOND now make the finish available in Australia.
ABOUT: AAF ANODIC BOND
What does Pre-Anodising Do?
Pre-anodising offers a unique and superior set of benefits unmatched by chemical conversion methods with exceptional durability and corrosion Resistance
The anodising process is an electrical transformation of the substrate surface. In the pre-anodising phase, it creates nano-pores, like a nano-scale honeycomb. The oxide layer is not sealed, unlike traditional anodising, preserving its anchoring ability.
This provides an excellent mechanical bond with powder, especially when baked and expanded into the substrate during the powder curing phase.
Key Features:
- Adhesion: The porous layer enables powders to mechanically anchor deeply.
- Corrosion Resistance: The oxide provides a passive corrosion barrier.
- Edge Cover: The oxide grows uniformly—even on corners—preventing edge-pull thinning. This is powder coatings weakest point and the most vulnerable to corrosion.
- Mechanical Strength: The oxide layer is harder than the base metal itself.li>
Over and above traditional chemical conversion processes, it enhances surface protection, improves adhesion, and significantly extends the durability of powder coating—even in the harshest conditions.
This process uses rapid anodising to create an approximately 5 t 10-micron protective layer on the aluminium surface. The anodising also forms micro-pores, which increase adhesion and bonding strength.
ANODIC BOND – matching improvements in Powder Technology
Advancements in Powder Coatings for Architectural Applications
Over the past few decades, architectural powder coatings have made significant strides in performance, durability, and design flexibility. The introduction of super-durable polyester technologies, followed by fluoropolymer ultra-durable systems, has greatly expanded the palette of finishes available—offering not only exceptional longevity but also an unrivalled choice of colours and aesthetics for architectural design.
Today, warranties of 15 to 30 years are common. Yet for true long-term sustainability, the industry’s focus is shifting toward extending service life even further.
Matching Coating Performance with Pretreatment Systems
Achieving this goal requires more than just advanced coatings—it depends on adopting the best possible pretreatment methods. At this point, the industry faces both headwinds (regulatory change, alloy variability) and advancements (innovations such as pre-anodising) that are reshaping the future of protective finishes.
About the Options for Pretreatment – and why they are important?
Pretreatment Systems Are Changing – The two issues.-
NO CHROME:
For decades, Chromate Chemical Conversion (CCC) has been the gold standard in pretreatment of aluminium for powder coating. It has delivered consistent, high-performance corrosion resistance and durability, and has been the universal choice across the industry.
However, driven by both regulatory changes (Chrome systems banned in Europe 2024) and safety considerations, significant change is now underway. After years of discussion and research, non-chrome pretreatment systems have now been developed. Whilst the new systems meet minimum corrosion standards, they do not match the performance of CCC.
Most new Australian powder coating plants employ non-chrome systems.
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RECYCLED ALUMINIUM
Secondly, a greater use of recycled aluminium introduces alloy variations that challenge the durability of conventional pretreatment methods. As approximately 40% of Australian extrusions are imported this is important. In addition, Australia is reintroducing aluminium recycling, a process also important for the environment.
However, new studies provide evidence that recycled aluminium, if not up to required benchmarks, will have a compromising effect on the pretreatment processes for powder coatings. As such, new standards are now being established to classify pretreatment processes dependent on alloy.
Addressing the Changes: International Research and Recommendations.
The most advanced research into powder coatings is undertaken by Qualicoat International. Originally a European based Audit and Accreditation system and now expanded globally. The classification of Qualicoat coatings are also referred in the AS 3715 of Architectural Powder Coatings.
The above changes affecting pretreatment systems has been of major concern and research. In May 2023, Qualicoat issued their Recommendations for Corrosion Protection.
The table below summarises Qualicoat recommendations.
Europe; Japan; Middle East; China
📄 Recommendations for Corrosion Protection
In summary, the electrochemical process of pre-anodising is now recognized as the only method HIGHLY recommended pretreatment process for powder coatings.
The pre-anodising process, combined with the latest ultra-durable powder coatings, delivers the highest level of durability and sustainability in modern powder coating architectural applications.
Alternative Method of Improving Corrosion Protection – (Primer + Finish)
As also recognised by Qualicoat in the recommendations, the “Application of a 2-layer- coating systems (Primer + Finish) will improve the covering of edge radius”.
The Australian Standards AS 3715:2025 also list “options” of 2-layer- coating systems to provide methods to improve the pretreatment process, and marks as mandatory on perforated/mesh aluminium items.
Otherwise, it is noted the new AS3715:25 Appendix G refers to “Flash Anodising” with some direction for process. However, it also notes the powder supplier should be consulted prior to use.
Disadvantages of Double Powder Coating
While double powder coating increases total coating thickness and delays exposure of weak points over time, it has several drawbacks:
- Missed Opportunity for Optimal PretreatmentBy simply adding more layers, the process does not take advantage of the best available pretreatment technologies. A superior pretreatment applied before coating could significantly enhance long-term durability without relying solely on thickness.
- Higher Cost and Environmental ImpactAdditional powder layers, including a primer coat, push the coating thickness to a minimum of 120 μm. Although this can improve performance, it also increases material cost and embodied fossil fuel content, raising environmental concerns.
- Limited Correlation with Service LifeThe new AS 3715:2025 standard highlights that atmospheric erosion rates of powder coatings rarely exceed 3 μm per annum. This suggests that even thinner coatings can provide adequate protection over time. Warranties should therefore be viewed as guidance on serviceable life, rather than absolute guarantees.
The Australian Landscape
Many Australian powder coating facilities have moved away from chromate systems due to the cost and compliance preferences of OH&S regulations.
What This Means for Our Customers
AAF are pleased to offer both chemical pretreatment and ANODIC BOND.
Australia’s climate – from humid coastal zones to dry interiors—places stress on architectural finishes. These diverse atmospheric conditions, classified in AS 4312, are critical in determining the appropriate pretreatment system for architectural powder coating.
Once environmental customer assessment are made, AAF is pleased to offer the most suitable pretreatment processes.
ANODIC BOND – Sustainability and Environmental Considerations
🌿 Extend Performance. Elevate Sustainability.
- Extends Service Life – The ultimate pretreatment for lasting durability.
- Reduces Costs – Simply replaces existing pretreatment costs and avoids the cost of twice powder coating.
This dual benefit—environmental excellence combined with
performance enhancement for powder coatings—positions anodising in general
as the prominent technology in achieving sustainable architectural solutions.
While there are environmental limitations for powder coatings with associated with the embodiment of fossil fuel-based materials, they remain a cornerstone of architectural design.
Their ability to deliver colour flexibility, aesthetic value, and durability contributes significantly to the architectural legacy of buildings, particularly in Australia’s urban and coastal environments where exposure to elements is a constant challenge.
AAF ANODIC BOND create the ultimate pretreatment support to maximise the longevity of these powder coatings
AAF Anodic Bond – Offsite Processing
Qualicoat have updated pre-anodised processes to be allowed as an external option for powder coaters. Procedures are strictly regulated to allow for the pre-anodising is to be done offsite. AAF Serving the Industry will work with other powder coaters to provide the Anodic Bond pretreatment, if specified, subject to compliance regulations.
The result is superior durability and resistance to corrosion. The ANODIC BOND film grows on edges which adds protection at powder coating weak points where film thickness significantly reduces. And at bare ends, from sawn edges in manufacture, the anodic film provides “the only method of 100% protection against the spread of filiform corrosion.”
AAF ANODIC BOND now delivers a process that meets the industry’s goals of long-term sustainability and uncompromising durability—proven in demanding architectural environments and essential wherever maximum durability is required.
What is Edge-pull and where are “bare sawn” surfaces?
Powder and paints are primarily applied through spray systems. A coating applied to a sharp edge will pull back from the edge, leaving the edge with a lower film build. This is known as “edge pull” and creates weak points which are more susceptible to edge corrosion
Architectural facades and structures are fabricated by cutting from long pre-coated lengths of aluminium.
Anticorrosive sealing compounds are used to assist protect non- powder coated bare mitre/butt/ joints. Pre-anodising protects, especially from the dreaded creeping filiform corrosion.
About: A more detailed summary of the Three Pretreatment Systems
- Chromate Conversion Coating: Historically used, excellent corrosion resistance. The main advantages they passivate the aluminum, reducing its reactivity. Secondly forms a gel-like, self-healing layer that inhibits corrosion.
- Non-Chromate Conversion Coatings:
- Zirconium-, titanium-, or silane-based.
- Lower environmental impact (RoHS/REACH compliant).
- The process chemically modifies the aluminum surface to create a nano-thin, amorphous or crystalline phosphate/silane/zirconium layer.
- Does not share the self-healing process of chrome chemical conversions
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- Pre- Anodising: AAF Anodic Bond (or Qualicoat Pre-Ox)
Comparison Table: Pretreatment Options for Architectural
| Feature / Parameter | Chromate Conversion (CCC) | Non-Chromate Conversion (NCC) | Pre-Anodising (Anodic Bond) |
|---|---|---|---|
| Corrosion Resistance | High (self-healing layer) | Moderate (no self-healing) | Highest – full barrier & edge protection |
| Environmental Impact | High (banned in EU 2024) | Low (RoHS/REACH compliant) | Low – sustainable & green building ready |
| Regulatory Compliance | Declining (safety & chemical bans) | Compliant but lower durability | Fully compliant & future-proof |
| Performance on Cut Edges | Moderate protection | Limited protection | Full protection – prevents filiform corrosion |
| Durability in Harsh Climates | Good | Moderate | Outstanding – proven in marine/coastal use |
| Cost Efficiency | Moderate | Lower upfront cost | High – replaces double coating costs |
| Global Recognition | Historic standard | Transition technology | Endorsed by Qualicoat & IST Germany |
Summary
Global Recognition
Pre-Anodising is the Gold Standard
🔹 Qualicoat (Europe)
“The new QUALICOAT additional label for best aluminium corrosion protection. Highest corrosion protection is offered by pre-anodised and coated aluminium products.”
🔹 IST International Surface Technology – Germany “Pre-anodising is still considered the top class of chemical pretreatment processes for aluminium.”
🔹 Qualicoat UK
“… A more expensive process, as statistically it is the only method of 100% protection against the dreaded filiform corrosion.”
As Pre-anodising Pretreatment becomes more specified, so will the availability of pre-anodising plants.
In Europe, where there is a focus on sustainability and maximum durability, facilities are changing pretreatment processes to address demand.
Some plants in Europe have now integrated a “pre-anodising” process into the vertical line pretreatment systems. – refer photo.
