SCIMED LTD
yet to agree a sunset date for banning its use as an
architectural aluminium pretreatment, as a result
these chrome based systems will continue to be
available for use.
Global HQ, QUALICOAT Zürich, is currently
working to ensure that the few applicator production
testing failures still reported, are reduced to 0%.
The only non-controlled area of the powder coating
process is the aluminium alloy itself. Extensive
research into the quality of the aluminium used
in architectural coatings is being undertaken
in a new QUALICOAT working group. Known as
‘QUALICOAT 3.0’, it is currently looking into the
impact of various levels of recycled content within
aluminium extrusion on the adhesion of powder
coating under the available pre-treatment methods.
Ongoing training of lab technicians working within
applicator members, is a prerequisite of holding
a QUALICOAT licence. The next course is still
planned to take place in September at pretreatment
specialists Chemetall in Milton Keynes.
Lab technicians, who continually check the
quality of powder coating output in applicator
licence holders, require updating on the latest
methodology in testing and recording which
is provided by the course.
Copies of the sixteenth edition of
the QUALICOAT Standard, is available
through the UK Association website,
www.qualicoatuki.org together with
an up-to-date list of licensed Powder
Suppliers, Pretreatment Suppliers and
Applicators. Printed literature and
telephone support is available from
QUALICOAT UK & Ireland Head Office
in Birmingham on 0330 236 2800
or email [email protected].
The Association can also be followed
on Twitter @Qualicoatuki.
Quality control for industry’s
most common plated finish
Electroless nickel (“EN”) is
industry’s most common plated
finish. It’s widely used for
applications that demand wear
resistance, hardness and corrosion
protection – particularly if parts
have complex geometries. It is
also used in PCB manufacturing
within a process known as ENIG -
electroless nickel immersion gold.
EN is most valued by manufacturers because it is
electro-less – and thus does not need electricity
to run – and because deposits are highly uniform:
EN plates evenly regardless of substrate shape.
This is an important advantage over electroplating,
which is subject to flux-density issues due to the
electromagnetic field which shifts with surface
profile. It also has a wide deposition window:
from 10 microinches to about 4 mils.
Electroless nickel is either nickel phos or nickel
boron alloy. In either case, the percent of
phosphorus in the reducing agent is a metric
whose importance can’t be overstated. EN is,
in fact, classified by its phos content: low at 1-4%,
mid at 5-9% and high at 10-14%.
Quantifying phosphorus is critical to EN plating
primarily because of its direct effect on corrosion
performance, and on hardness. The exceptional
hardness of low-phos EN (typically 500-720 HK)
has made electroless nickel a popular replacement
for chromium. (To put this in context, the hardness
range of electrodeposited nickel is 150-400 HK.)
Many platers don’t test for phos content in-house,
however, relying instead on their chemical suppliers
- or an outside lab.
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