Manufacturing parts and other elements in the machining process is often one of the steps in the whole process. In addition to shaping the final (expected) form – according to the given specification – manufactured parts are often subjected to additional processes, especially focused on bettering their surface finishing.
The main goal of such processing is adding additional features for manufactured parts – like better corrosion protection or resistance to mechanical damage. Achieved in such a galvanic process layer has also a good aesthetic value that on the one hand makes it look good, and on the other – protects the metal parts. That is why the galvanic treatment has many applications – not only in industries that demand better corrosion resistance of parts (eg. shipyard, automotive) but also in branches that are focused on aesthetics (eg. home decor).
What is a galvanic treatment and what is that process?
The main goal of galvanic treatment (called also galvanization or – by the book – galvanostegia) is the formation of a thin oxide layer on the surface of the part (galvanic coating). It is an electrochemical process – that combines properties of metal alloys (eg. steel, aluminum, copper) and electrolytic solution under electrical current (with proper solution and current). In effect, the surface layer created in the process protects part against the corrosion and increases aesthetic values.
To achieve that result metal part is placed in a specialized galvanic bath with electrolyte (eg. sulfuric acid with proper concentration) that is connected via electrodes to a galvanic power supply, often – three-phase – to deliver electrical current. In contact with the electrolyte – during the galvanic bath – on the surface of the part created a thin galvanic layer.
Parameters of particular galvanic processes depend on:
- type of processed metal (steel requires different processes and parameters than aluminum or titanium),
- selected process (zinc coating requires different parameters than the aluminum anodization process),
- expected results of the process.
Types of processes that can be included in the galvanic treatment
Galvanic processes are often named after the element that the oxide layer is made of. Among the most often used treatments, the most often used are:
- chrome plating – a process that crocuses on the saturation of the surface with the chrome elements. It delivers very good aesthetic results, provides good corrosion resistance, and hardens the surface. That makes chrome plating a very good galvanic process for parts that should have significant abrasion resistance. It is worth mentioning – chrome coating is a often finishing process,
- zinc plating – saturation of the surface with zinc elements. This is one of the most price efficient (if not: the most inexpensive) type of galvanic processing, mainly due to the low complexity of the process and vast availability of the technology. In common language 'zinc steel sheet' has a good enough corrosion resistance to protect parts that are placed outside without any additional processing (often – even painting),
- copper plating – a process that focuses on the saturation of the metal surface with copper elements. That galvanic treatment has mainly aesthetic features and is often executed as a chemical, not galvanic process (when aesthetic-focused). On the other hand – galvanic copper plating provides better quality of the surface (eg. improves mechanical rigidity). It is worth mentioning that copper plating is also a preparing process for other galvanic treatments, eg. nickel plating,
- cadmium plating – a galvanic process often used for parts that will be exposed to salt water or other alkaline agents. Provides very good corrosion resistance but the main disadvantage of that treatment is its complicity and the requirement to execute it in well-ventilated spaces. Cadmium fumes – just like those produced in the process cyanide fumes – are highly toxic,
- nickel plating – is used mainly to protect alloy surfaces against corrosion. Can be executed chemically and electrochemically (galvanic process). The most often used to improve features of the steel surface. Although provides less efficient effects than chrome plating, it is less expensive – that is why it is one of the most popular galvanic treatments today,
- phosphorus plating – focuses on saturating alloy surfaces with phosphorus elements to improve corrosion resistance and decrease friction. Contrary to other galvanic processes, phosphorus plating deteriorates aesthetic features of the surface on purpose (eg. reflexivity reduction). The main reason is to prepare parts for further finishing processes, like painting. That treatment was – and still, to some extent, is – used in the military industry (eg. to process steel gun frames),
- aluminum anodization – a very popular galvanic process, dedicated almost exclusively to aluminum alloys (to some extent – also titanium). Anodized coating provides very good mechanical and aesthetic features for the aluminum part that can be also improved with additional coloring coating. That process is easily scalable, so the thickness of the anodic layer can relate to its look and provides protection (if needed – eg. hard anodizing creates a thicker layer of aluminum trioxide and provides very good surface protection).
Advantageous of galvanic coating
There are many types of galvanic coating that provide different effects – visually and mechanically. But each of these processes delivers a few key advantages:
- an additional layer of material – created on the part surface – provides good or very good mechanical protection and corrosion resistance,
- galvanic processes allow to create even coat on the whole surface of the part, even with complicated shapes,
- sometimes – such galvanic coating can improve the aesthetic features of the part, decrease friction, remove tool marks, and sometimes – prepare part for the further treatments (eg. copper coating before nickel plating).
Applications of the galvanic coating
Galvanic treatments are often selected as one of the steps in the manufacturing process – mainly due to the advantages mentioned above. Better corrosion/abrasion protection and improved mechanical features make the galvanic coating an industry-standard in areas like:
- automotive industry – to improve mechanical parameters of key vehicle parts (eg. engines, drivetrain or chrome-plated wheels, and even whole car body parts),
- outdoor equipment – subjected to the galvanic process accessories are popular due to their rigidity and resistance to many factors – from tent frames and camping dishes to pickax and lightweight seat frames,
- home accessories and 'home decor' – aesthetic features of the galvanic coating in that applications are the most important but additional corrosion and abrasion resistance are important in the kitchen, bathroom, or outside (eg. accessories exposed to the weather all year).
The cost of the galvanic treatment depends on the selected process, its complication, and the number of parts that should be coated. If you need a quotation for a galvanic process – contact RADMOT.
One order, many benefits – this is how you collaborate with RADMOT
At RADMOT, we offer CNC milling services, CNC turning services, as well as many additional services, including washing, aluminum anodizing, laser marking and assembly. We have at your disposal over 80 modern machines in our machine park, all from renowned manufacturers. Download the presentation and check on which machine tools we produce CNC turned parts and CNC milled parts.
Contact us and tell us what you need. We have been providing CNC services for almost 40 years. Our valuation is completely free. And if you're in doubt about which technology will work best for you, our expertise is at your service.
