Product Introduction

Brightener for alkaline zincate type zinc plating
Hyperzinc Series
Nippon Hyomen Kagaku Kabushiki Kaisha R & D center

Introduction

after plating. In the past, "chromate treatment" using

Since steel members are inexpensive and easy to process,hexavalent chromium was used, but the use of hexavalent

they are used in various fields including automobiles,

chromium was regulated by the ELV Directive which cameelectric products, building materials, etc. However,into effect in 2000 and RoHS Directive which came into

untreated steel members are susceptible to rust and cannoteffect in 2006, and in recent years, it has shifted to "trivalentmaintain aesthetics and mechanical strength for a longchromium conversion treatment" which does not use

period of time. Therefore, it is common for steel members tohexavalent chromium.1
We are developing trivalent chromium treatment agentsbe subjected to rust prevention treatment.
Zinc plating is widely used as a typical rust prevention

as a "Tryner" series (see separate document).

treatment for steel because it has a "sacrificial protection"effect to suppress corrosion of steel members by preferential

Product Summarycorrosion of zinc, which has a larger ionization tendency

The JASCO Hyperzinc series is a brightener for alkaline

than steel in a corrosive environment. Though there arezincate baths, and has a variety of distinctive products tovarious methods to apply galvanizing to steel, electro-provide optimal solutions for plating methods (barrelgalvanizing is suitable for mass treatment of articles withplating, rack plating), shapes and applications of articles,

complicated shapes. Electro-galvanizing is a method ofetc. (Table 1)

precipitating zinc on a surface by electrolyzing an article asa cathode in a plating solution and can be roughly classified

Features of the Hyperzinc series

into a "zincate bath," "cyanide bath," and "acid bath."

・Excellent uniform electrodeposition"Zincate bath" which contains no poison even in those and・Uniform plating appearance

is easy to treat wastewater has grown greatly in recent years.

・Good compatibility with trivalent chromium conversion

Electro-galvanizing has a current density gradient due tocoatings

the shape of the object to be processed and the positional

・Iron anode can be used.

relationship with the counter electrode, and variations in the・Wide operating range and easy bath management

plating film thickness with this may become a problem.
"Hyperzinc" series is a uniform electrodeposition typezincate bath brightener which greatly improves that problem.

In electroplating, the plating film thickness varies due tothe high current density portion of the portion near theIncidentally, zinc plating is generally performed chemical

anode plate or the convex portion of the article and the low

conversion film treatment for protecting the plating film

current density portion of the portion far from the anode

Table 1: Hyperzinc Lineup
Product name
Hyperzinc 300
Hyperzinc 7900ABS
Hyperzinc 7900L
Hyperzinc 9000ABS
Hyperzinc 9000FG
Hyperzinc 9500

Plating method
Barrel plating

Rack platingFeatures
High conc. type, glossiness maintenance after baking
Highly resistant to bending or caulking with good film properties
Compatible with small items that tend to overlap
Highly resistant to bending or caulking with good film properties
Have superior resistance to impure metals
High conc. type, highly resistant to bending or caulking with good film properties
202010301 JASCO Nippon Hyomen Kagaku Kabushiki Kaisha 1[Product Introduction] Hyperzinc Series

plate or the concave portion of the article. Hyperzinc shows

anodethe superior throwing power compared with theconventional zincate bath by inhibiting the plated
precipitation in the high-current-density part andcathode(pipe)

facilitating the plated precipitation in the low-currentdensity part1 (Figure 1).

Test piece: diameter 16mm
length 100mm
Current density: 2A/dm2
Time:
30minutes
Anode-cathode distance:
20mm

Inner surface of the pipeHyperzinc
ConventionalHyperzinc

zincate bath
Film thickness(μm)

Comparison of film thickness distribution
on the inner surface of the pipe
Hyperzinc

Conventionalzincate bath

Conventionalzincate bath
Distance from the pipe end (cm)Figure 2: Comparison of plating throwing power of
Figure 1: Comparison of film thickness distribution

low current parts(barrel plating)
Further, it is compatible with "trivalent chromium
conversion treatment" and the chemical conversion film is
It is also excellent in the throwing power to deposit platingon the ultra-low current density portion, which is the innereasier to thicken than the conventional zincate bath, so thathigh corrosion resistance can be obtained (Figure 3).

surface of the pipe parts, and a uniform glossy plating
appearance can be obtained from the high current density
portion to the low current density portion. Figure 2 shows acomparison of the throwing power of the inner surface ofthe pipe when the anode is placed on only one side tocreate an extreme current density gradient and the pipe isplated.

Treatment process
The general processes of electro-galvanizing are in theorder of "pretreatment," "plating," and "post-treatment.""Pretreatment" is a step of removing stains and rustadhering to an article and is performed in the order of"degreasing" for removing oil stains, "pickling" forSST (hr)

0hr

120hr

240hr

360hr

480hr

Hyperzinc

Conventionalzincate bath

Figure 3: Comparison of corrosion resistance of hyperzinc and conventional zincate baths with trivalent chromium
chemical conversion coating (JIS Z2371)
202010301 JASCO Nippon Hyomen Kagaku Kabushiki Kaisha 2

[Product Introduction] Hyperzinc Series

Pretreatment

Degreasing

Pickling

Post-treatment
Zinc

Electrolytic
cleaning

plating

Activation

Trivalent

chromiumconversion

DryingFigure 4: Zinc plating process (general processing process)removing rust, and "electrolytic cleaning" for removing

brightener for zincate baths in Japan, and it is now wellsurface residues after pickling. "Plating" is a step ofreceived by many customers both domestically and abroad.

generating a plating film by electrolysis, "post-treatment"

It continues to evolve day by day from the results cultivatedis a step of protecting a plating film, and in recent years,

in these large numbers of sites and is a brightener capable of"trivalent chromium conversion treatment" is the

responding to all needs of the site.

mainstream.
The processes from pretreatment to post-treatment aregenerally carried out continuously (Figure 4).

Literature
1: Hideo Susa; J. Surf. Finish. Soc. Jpn. Vol. 70, No. 8, pp.

Mechanisms

388-393 (2019)

The brightener of zinc plating is composed of a primarybrightener which forms a uniform and smooth plating filmby suppressing deposition of zinc by electrolysis and asecondary brightener which imparts brightness to the platingfilm. Primary brightener of Hyperzinc uses a special watersoluble polymer which exhibits higher the current density,the stronger the inhibiting force. By the primary brightenershifts the current density distribution in the article to themiddle and low current density portions, plating thicknessof these areas are increased, and plating thickness of highcurrent density area is decreased. By this, it became possible
to provide uniform plating thickness to wide current area
compare with the conventional brightener.
In addition, when an iron anode is used in a conventionalzincate bath, the oxidizing atmosphere around the anode isstrong and the decomposition of the brightener is accelerated.
Therefore, it is common to use a zinc anode in which theoxidizing atmosphere around the anode is unlikely to bestrong, but a special water-soluble polymer used inHyperzinc brightener is hardly decomposed even under anoxidation atmosphere, so that the iron anode can be used.
Furthermore, to suppress the zinc concentration fluctuation
caused by dissolution of the zinc anode, it was necessary topull out the anode plate during a long-term operation rest,
but in the case of the iron anode, it becomes unnecessary topull out the anode.

In closing
The JASCO Hyperzinc series has been marketed over 20years as a pioneer of uniform electrodeposition type202010301 JASCO Nippon Hyomen Kagaku Kabushiki Kaisha 3