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Metals

Metals

Galvanically deposited metal layers to improve component characteristics.

What impresses us about the goldfish?

What impresses us about the goldfish?

The goldfish has an impressive colour scheme. Electroplated products are also impressive with their surfaces and appearance and also provide a number of convincing component properties after treatment.

The process

Electrochemical deposition of a thin metallic layer on the surface of a conductive metallic component is called electroplating. This primarily improves the characteristics of a component such as, for example, wear resistance, corrosion resistance or anti-friction properties.

A metallic or conductive component is connected to the negative pole (cathode) of a rectifier and placed in a water-based electrolyte in which conductive salts and metal ions of the metal to be deposited are contained. At the same time, the positive pole (anode) of the rectifier is connected to metal plates consisting of the metal to be deposited. Turning on the rectifier, a current begins to flow, which dissolves metal ions in the electrolyte on the side of the anode by oxidation and thus continuously supplies the electrolyte with new metal ions. At the same time, a metal layer is deposited from the enriched electrolyte onto the component, which is attached to the cathode.

  • Characteristics

    The properties of the metal layers are naturally different.

    Gold layers generally exhibit high ductility, tarnish resistance, good solderability, and low specific electrical resistivity. AHC offers conventional gold layers as well as gold/cobalt alloy layers, which are more wear resistant and harder.

    Chrome layers offer good corrosion protection with excellent appearance and high hardness. AHC produces bright chrome, matt chrome and black chrome coatings. Often, chromium is applied in combination with copper and nickel (Cu-Ni-Cr coatings). Copper has a high ductility. Therefore, as a sub-layer, it counteracts tensions between the component and the layer system. Copper ensures good adhesion and provides a corrosion barrier in the combination coating. Copper plating has a levelling effect and a decisive influence on the gloss effect of the finished coating. A final nickel plating increases corrosion resistance.

    A further increase of the corrosion protection and the wear resistance is possible with hard chrome.

    Copper and nickel are also applied individually at AHC; nickel can be a gloss, matt or velour nickel. Nickel coatings from nickel sulfamate electrolytes (nickel sulfamate coatings) have a low residual stress, which can also be converted into compressive stress. They can be deposited in much thicker layers than classic nickel coatings. Nickel sulfamate coatings are very ductile and provide good protection against wear and corrosion attack. The coatings can also be machined without difficulty.

    Silver coatings have very high electrical conductivity, good chemical resistance and high ductility. They are well suited for soldering, reduce contact resistance and have a self-lubricating effect.

    Tin coatings are also good for soldering and have a high ductility. They have good electrotechnical properties and offer excellent corrosion protection, including on copper and steel. They are chemically resistant to organic acids in the absence of oxygen. Like silver coatings, tin coatings are self-lubricating.

  • Base Materials

    Galvanic metal coatings are applied to the following base materials at AHC:

    Aluminium alloys: gold, gold cobalt, nickel sulfamate, silver and tin.

    Non-ferrous metals and ferrous materials: gold, gold cobalt, chromium, hard chrome, copper, nickel, nickel sulfamate, silver and tin.

    Stainless steel: gold, chrome, hard chrome, copper, nickel, nickel sulfamate, silver and tin.

    Titanium materials: gold, gold cobalt, silver and tin.

    Die-cast zinc: gold, chrome, hard chrome, copper, nickel, silver and tin.

  • Field of Application

    For example, gold and gold / cobalt alloy coatings are suitable for connectors for the electronics industry, batteries, LED manufacturing, professional halogen lamps, aerospace components, radar equipment, and high temperature brazing.

    Chromium coatings are popular in the automotive, furniture and many other industrial sectors for their decorative appearance. Fields of application of hard chrome are heavily stressed workpieces such as brake discs, ball valves in pipelines or rollers and cylinders of all kinds in the printing industry, film production, paper production, the food industry and in mechanical engineering.

    Copper coatings alone are seldom needed, as copper tends to turn green, especially in moist air. However, it can serve as a painting substrate.

    Nickel-plating as a final coating for components is a possible alternative to chrome coatings in the decorative sector. As a final coating, nickel can be polished very well from matt to glossy. Nickel sulphamate is especially recommended when extremely thick, stress-free coatings are needed. Such nickel coatings also serve as a primer for thermal spray coatings.

    Due to their outstanding electrical conductivity, silver coatings are frequently used in the electronics, high-voltage and telecommunications industries, amongst others: electrical switches, high-voltage conductors or housings. In addition, silver is often used in the food industry and the chemical industry. For example, stainless steel fittings and shut-off valves are silver plated to prevent seizing and corrosion.

    Tinning is mainly for technical parts that must be electrically conductive, solderable and electromagnetically shielded: housings for electrical plugs, plug contacts. Self-lubricating bearings are also an application for both tin and silver coatings.

Product enquiry

If you would like to tell us something about the product presented here, you are welcome to do so. Your enquiry, your comment, your wishes will be forwarded directly to your personal contact person.

More Surface Treatments

  • DURALLOY®

    DURALLOY®

    Optimisation of frictional processes by means of specially structured metal surfaces

    to the process
    DURALLOY®
  • SELGA-COAT®

    SELGA-COAT®

    Selective galvanic finishing of metal surfaces

    to the process
    SELGA-COAT®
  • DURNI-COAT®

    DURNI-COAT®

    Functional finishing of metals by means of electroless nickel plating

    to the process
    DURNI-COAT®
  • CompCote®

    CompCote®

    Aluminium oxide polymer composite coatings

    to the process
    CompCote®

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