Technical terms | Galvano Hengelo

Technical terms

Galvanization:

Galvanization (definition): the application of an adhesive metallic coating to an electrode (product) by means of electrolysis, with the aim of providing the surface thereof with properties or dimensions that differ from the base material.

Rectifier:

An electrical device in which alternating current is converted into direct current.

Anode:

The electrode that is connected to the rectifier’s positive pole is called the anode; the positive electrode. The anode is an electrode that can be dissolved in a galvanic bath.

Cathode:

The electrode that is connected to the rectifier’s negative pole is called the cathode; the negative electrode. The product in a galvanic bath is typically the cathode.

Electrolysis:

The collective name for the processes that occur when an electric current is sent through an electrolyte (conducting fluid). An anode and a cathode are required for the supply and removal of the current.

Nobility:

Not all metals have the same tendency to make a connection with other substances. The smaller the tendency to connect, the greater the metal’s nobility.

Ampere:

A unit of electrical current. 1 ampere (1 A) is the current that precipitates 4,025 g of silver per hour from a silver bath.

Volt:

A unit of electrical voltage. 1 volt (V) is the voltage that drives 1 ampere of current through a conductor with a resistance of 1 ohm.

Coating thickness:

The thickness of the metallic coating, expressed in microns or micrometres (μm).

Micrometre:

A micrometre or micron is one thousandth of a millimetre, indicated by the μm symbol, which means one millionth of a metre (micro, abbreviated to μ, means millionth).

Rack work:

Products that are hung on hooks or racks that conduct the current are hung or clamped for the galvanization process. Rule of thumb: For larger and/or damage sensitive products.
Rule of thumb: For larger and/or damage sensitive products.

Barrel work:

Typically used for small (bulk) products that cannot be hung due to their shape. These are treated as bulk material in special galvanizing drums.
Rule of thumb: For smaller and non-damage sensitive products.

Corrosion:

The often undesirable (chemical or electrochemical) damage to a metal that occurs when exposed to adverse conditions (moisture and salts). This results in corrosion products such as metal oxides. The rusting of iron is a good example.

Ductile:

Means soft and highly deformable. Thus, a ductile coating can be readily deformed without cracks or fissures. Tin and silver are good examples of relatively soft and extremely ductile coatings.

Electroless (autocatalytic) metallic coatings:

With an electroless or autocatalytic bath, no (direct) electrical current is required to precipitate a metal. These processes make use of so-called reducing agents that ensure that the dissolved metals are converted into metallic form. The metallic particles form an extremely uniform coating on the product. This metallic coating forms wherever the bath fluid comes into contact with the product.

Passivation:

A process that a metal surface or galvanic metal precipitation undergoes to make the surface non-reactive (less corrodible). This results in improved corrosion resistance. Many galvanic precipitates that are used for corrosion protection are passivated as the final treatment. Yellow passivated zinc is a good example.