Halar (ECTFE) Coating for Acid-Duty Washers
AST applies a Halar (ECTFE) thick-film chemical barrier to washers running in aggressive acid service for Latrobe Magnesium — an Australian critical-minerals producer.
Chemical-barrier work is judged on one thing: whether the film is continuous. On a washer — a small part with edges, a bore and a large surface-to-mass ratio — that is a harder result to achieve than it is on a flat panel, and a harder one to take on trust. This job was built and released on documented holiday-test evidence.
Small parts, aggressive chemistry, high consequence
Washers in acid duty sit in one of the harder positions on a process plant. They are small, low-value components in isolation, but they are in continuous contact with aggressive chemistry and the cost of replacing them is measured in plant downtime rather than in the part. The customer needed washers protected to a standard that would hold in aggressive acid service — and needed evidence that the barrier was continuous before the parts went back on site, not an assurance that it probably was.
- Continuous exposure to aggressive acid duty
- Small components, disproportionate downtime cost
- Barrier continuity had to be demonstrable
- Repeatable specification across orders
Build the barrier, then prove it
The washers were prepared and coated with a Halar (ECTFE) thick-film barrier system built up to a chemical-barrier film. Small parts of this kind need careful racking and handling so the film builds evenly across the whole surface rather than thinning at the edges. Every coated part was then holiday/spark tested using the wet sponge method AST runs as standard on Halar and Tefzel barrier systems, and the result documented as a pass before release.
- Controlled substrate preparation
- Halar (ECTFE) thick-film barrier build
- Racking and handling to keep film build even
- Holiday/spark tested, pass documented per batch
Halar (ECTFE) — the chemical barrier system
Halar (ECTFE) is AST's chemical-barrier system for aggressive acid duty. It is applied as a thick film rather than a thin release coating, and the extra build is what does the work — a continuous barrier between the substrate and the process chemistry. Holiday/spark testing is standard on Halar systems at AST, which is why barrier continuity on this job was verified rather than assumed.
- Thick-film ECTFE chemical barrier
- Specified for aggressive acid service
- Holiday/spark testing standard on Halar
- Materials Certificate of Conformance available
Into service, and then repeat orders
The washers went into acid-duty service and the customer has continued to order. The work now runs as repeat batches to the same specification, with holiday-test documentation issued each time. Lead time is 7–10 working days from receipt of parts, and every job carries AST's lifetime workmanship warranty.
- Parts in acid-duty service
- Repeat orders to the same specification
- 7–10 working days from receipt
- Lifetime workmanship warranty
Holiday/spark testing is standard on AST Halar and Tefzel barrier systems — every part tested, every result documented, and the record issued with the job.
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Equipment in acid or aggressive chemical service?
Talk to AST about the media, concentration and operating temperature. Our team can recommend a barrier system and prepare a technical quotation.