50 different coating combinations

As a leading operator in the field, we can supply you with the most versatile and comprehensive range of surface treatments in Finland – we can provide your products with the best possible protection against corrosion as well as a visually appealing finish on any surface.

Our electrolytic surface and powder painting treatments are provided by our plant in Turku.

Our coatings provide functionality and flair – even for the most demanding needs

Our trained and skilled staff, laboratory, certified procedures and versatile measurement tools ensure a top-quality end product that can meet the most demanding specifications.

Our expertise is utilised in various electrical, vehicle, electronic, construction and mechanical engineering industry products.

Our selection of treatments provide added value

In addition to surface treatments, we offer a wide range of additional treatments, such as grinding, glass bead blasting, vibration grinding, polishing, various types of protection, assembly and heat treatment.

We can handle your product all the way to your customer packaging. Do you need something else in addition to these services?

Logistically cost-effective and reliable – from door to door

Together with our logistics partners, we can handle the transport of any product comprehensively and reliably to all of your end customers, both in Finland and abroad.

Electrolytic Coatings:

Aluminium anodizing
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    Maximum product dimensions:
    3,3 x 0,8 x 1,4 m

    Purpose/features

    An electrochemical coating process for aluminium products that forms an oxide layer on the surface of the product, providing good corrosion protection, a visually pleasing appearance and various operative features, such as hardness and abrasion resistance.

    The main factors that affect the appearance of the oxide layer are the surface quality of the raw material and the grade and purity of the aluminium that is used.

    Processes

    The anodizing process takes place in sulphuric acid solution. The colour of the oxide layer that is formed on the surface of the product can either be left as-is or it can be coloured black.

    Standard

    ISO 7599:2010(E)

Bright anodizing / chemical polishing of aluminium
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    Purpose/features

    Aluminium polishing is based on aggressively etching the aluminium surface with a chemical process that reduces the microprofile of the aluminium surface. The end result is a glossy finish.

    The polishing process can be used alone or it can be combined with an anodizing process. When used together, the product is anodized with a uniformly glossy oxide layer that provides it with good corrosion protection and an appealingly glossy finish, as well as hardness and abrasion resistance.

    In general, the chemical polishing of aluminium is suitable for many aluminium grades. However, the best and highest levels of gloss are achieved on clean aluminium.

Aluminium passivation
(Iridite NCP)
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    Purpose/features

    A chemical coating process in which a passivation layer that is compliant with the RoHS directive is formed on the surface of the aluminium. The passivation surface layer is almost colourless.

    The purpose of the surface layer is to provide products with good corrosion protection, a level of heat resistance (350 °C) that does not compromise any of its corrosion protection features, and a good surface for paintwork. Passivated aluminium can withstand the high temperatures required by the powder painting furnace.

    Standard

    EN ISO 12487

Silver plating
(+ passivation)
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    Maximum product dimensions:
    1,8 x 0,35 x 1,0 m.

    Barrel silver plating

    Purpose/features

    An electrochemical process that precipitates a uniformly glossy silver finish on the surface of a product. Silver plating is used to provide products with features that increase their electrical and thermal conductivity, hardness and wear. The process can be used to coat steel, copper and copper alloy surfaces as well as nickel-plated objects.

    Finishing treatments (passivation)

    Silver plating will darken over time, and the best way to protect silver-plated products against this natural reaction is to passivate them. The passivation surface is completely clear, so it will not affect the gloss of the original surface or any of the other features that have been achieved with the silver plating process.

    Every silver-plated product is passivated using a RoHS-compliant process.

    Standard

    SFS-EN ISO 4521

Bright chrome plating
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    Maximum product dimensions:
    2,7 x 0,5 x 1,3 m

    Purpose/features

    An electrochemical process that precipitates a uniformly glossy, well-spread and beautiful, bluish chrome surface on a product.

    In the so-called decorative chrome plating process, nickel is always used as undercoating under the chromium. Chromium improves the corrosion protection and appearance of nickel-plated products.

    Bright chrome plating is used to provide products with decorative features, hardness and wear-enhancing features, as well as extremely good protection against corrosion.

    Standard

    EN ISO 1456

Copper plating
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    Maximum product dimensions:
    2,7 x 0,5 x 1,3 m

    Purpose/features

    An electrochemical process that precipitates a high-gloss, non-porous and well-spread copper surface on a product.

    Copper plating is often used as an intermediate coating for other coatings to provide additional features such as good coverage, adhesiveness and an additional layer of corrosion protection.

    The process can be used to plate steel, aluminium, copper alloy and zinc die casts.

    Choose from rack or barrel plating.

    Standard

    (EN ISO 1456)

Nickel plating
(+semi-gloss nickel)
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    Maximum product dimensions:
    2,7 x 0,5 x 1,3 m

    Purpose/features

    An electrochemical process that precipitates a high-gloss (mirror gloss), excellently spread and smooth nickel surface on a product. In addition, the process is ideal for double nickel plating processes (1st layer of semi-gloss nickel + 2nd layer of bright nickel), which provides products with particularly good corrosion protection features for outdoor conditions.

    Nickel plating is used to provide products with decorative features, hardness and wear-enhancing features, as well as extremely good protection against corrosion. In addition, nickel plating is used as undercoat for bright chrome plating. If necessary, the nickel plating can include several layers of undercoating to provide the product with additional features.

    Choose from rack or barrel plating.

    Standard

    EN ISO 1456

Stainless steel pickling
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    Maximum product dimensions:
    3,0 x 0,7 x 1,3 m

    Purpose/features

    Stainless steel pickling cleans the surface by etching any impurities such as oxide scale, stains and rust in welds. After this, a passivation layer (oxide film) is formed on the surface, providing protection against corrosion. Pickling improves paint adhesion.

    Pickling provides stainless steel products with a clean, metallic and silky smooth finish.

    Standard

    No applicable standard.

Zinc electroplating
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    Maximum product dimensions:
    3,0 x 0,7 x 1,3 m

    Purpose/features

    An electrochemical process that precipitates a high-gloss, excellently spread and smooth zinc surface on a product.

    Normally, as part of the coating process, all zinc-electroplated surfaces are passivated immediately after the zinc plating process, which helps prevent the formation of any so-called white rust on the surface of the zinc coating.

    Zinc coating is used to provide products with decorative features, glossiness, smoothness, a specific colour, a base for paintwork and good corrosion protection.

    Choose from rack or barrel plating.

    Passivations

    A conversion coating that is formed on zinc coating that helps protect the zinc surface from corrosion.

    The type of passivation is selected according to either the colour or the required corrosion resistance duration level:

    • blue
    • yellow (iridescent),
    • green or
    • black.

    Cr3+ blue passivation (RoHS-approved)

    A passivation bath for zinc coatings that produces a high-gloss and vibrantly blue passive layer. Based only on three-value chromium compounds. Gloss, colour and corrosion protection are preserved even in heat-treated items. This type of passivation provides a level of white rust resistance that lasts at least 100 hours (EN ISO 2081).

    Cr6+ yellow passivation

    A passivation bath for zinc coatings that produces an iridescent yellow Cr6+ chromate layer. This type of passivation provides a level of white rust resistance that lasts at least 168 hours (EN ISO 2081).

    Cr3+ yellow passivation (RoHS-approved)

    A type of yellow passivation for zinc coatings that is based on three-value chromium and provides a high level of corrosion resistance. The passivated surface is iridescent yellow in appearance. This type of passivation provides a level of white rust resistance that lasts at least 100 hours (EN ISO 2081).

    Cr6+ green passivation

    A Cr6+ green passivation bath for zinc coatings. The chromate layer provides products with a dark olive green film with an excellent level of corrosion resistance that matches the type of resistance offered by Cr6+-class yellow passivation.

    This type of passivation provides a level of white rust resistance that lasts at least 168 hours (EN ISO 2081).

    Cr6+ black passivation

    A Cr6+ black passivation bath for zinc coatings where a chromate layer provides a glossy, black and iridescent film on the zinc surface. This type of passivation provides a level of white rust resistance that lasts at least 48 hours (EN ISO 2081).

    Cr3+-Lanthane TR 175 thick film passivation (RoHS-approved)

    A passivation system for zinc coatings that is based on chromium level (III) and contains nanoparticles. The passivation layer provides products with a glossy and slightly silver-coloured iridescent film that features an excellent level of corrosion protection due to the nanoparticle technology that is used. This type of passivation provides a level of white rust resistance that lasts at least 250 hours (EN ISO 2081). It also includes good self-healing features that prevent the immediate formation of white rust in scratches that reach down to the zinc surface.

    Sealing treatment

    Sealing is a post-dip treatment for zinc-coated and passivated surfaces. It provides passivated products with additional corrosion protection.

    Varnish

    A colourless water-dilutable drying furnace varnish for zinc-coated and passivated surfaces. Varnish is used to protect areas that the zinc coating cannot reach, such as in tubular structures. In addition, the varnish provides additional protection against corrosion and prevents any subsequent changes in colour in the coating.

    Standard

    EN ISO 2081

Tinning
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    Maximum product dimensions:
    2,7 x 0,5 x 1,3 m

    Purpose/features

    An electrochemical process that precipitates a high-gloss and exceptionally smooth tin surface on a product. In addition, the precipitated tin coating features excellent soldering and electrical properties.

    This type of coating is ideal as a technical coating solution for electrical and electronic industry appliances.

    Choose from rack or barrel plating.

    Standard

    ISO 2093

Additional services:
Mechanical grinding/polishing, Glass bead blasting, Vibration grinding, Storage, Transport, Assembly, Packaging in customer packaging, Different protections...
  • Instructions for surface treatment product batches

    To enhance the quality of our customer service and supply chain, we ask our customers to include a shipment note with the following information in every product batch:

    - The customer’s complete contact information
    - Desired surface treatment, such as hot-dip galvanizing or zinc electroplating, etc.
    - In conjunction with zinc electroplating, the desired passivation method, e.g. yellow passivation.

    - Dispatch list specifying the contents of the batch to be galvanized along with their package information, e.g.
    4 pcs PP100*100*4 L=3500-4000 / 1 bundle
    6 pcs HEA 200 L=2500 / 1 bundle
    2 pcs FRAME PP80*80*3 1500*4000 / 1 bundle
    154 pcs WASHERS 50*50*2.5 / 1 pallet


    - The “work number” of the batch that is to be brought, e.g. site name
    - Information on possible finishing treatments (painting, etc.)
    - Information on any pre-agreed additional work, e.g. thread opening, surface protection or special packaging.
    - The necessary drawings and instructions on surface protection and special packaging must also be provided

    - In the batches to be delivered to the Turku plant, specifications on any additional work preceding the surface treatment, such as polishing, glass blasting or vibration

    - Information on possible further deliveries (delivery address, cargo carrier, payer, possible contract numbers, etc.)

    - The possible tender number associated with the product batch

    If the customer orders the batch from a wholesaler or subcontractor, the identification information specified above must be provided with the batch as in direct customer deliveries.

    You can use the following shipment note when you are bringing your products in for hot-dip galvanization:
    Download the hot-dip galvanizing note here (Word File)

Aurajoki Oy

was founded in 1967 and specialises in metal surface treatment services and solutions. We produce, develop and design cost-efficient industrial service solutions – from the production process to the planning, finalisation and customer delivery process.

As a flexible service provider, we adapt to our clients’ every need: we can provide you with entire supply chains or even just individual services.

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