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Introduction To General Surface Treatments
Tantec has a focus on Plasma, Corona and Ozone Surface treatment to prepare and prime materials, usually to improve adhesion.
But the phrase ‘Surface Treatment’ is used for many different technologies and applications. It covers a wider range of ideas than just the equipment and processes we specialise in. So here are a few key surface treatments and more background to the surface treatment world.
What Is Surface Treatment?
Surface treatment is a broad term for a number of techniques which are used to change the surface properties of a material or component to give a more desirable and useful finish. The key identification of a surface treatment is that it is the interface of the material – it does not impact the entire material.
Surface treatments are a way of manipulating a materials surface to make it more usable. Many materials have good properties for an application and the fact that the material surface isn’t right can often be altered to suit the intended use.
Many metals are highly desirable for application such as body panels for vehicles, aircraft and ships, but their reactivity and issues around corrosion would render them useless without a surface treatment to cover and protect the core metal.
Light weight polymer structures, made cheaply and easily from polymers with high recyclability sound good but still require print, labels or adhesives to be used with them, but their non stick nature makes it difficult to bond to these materials.
It’s easy to consider large materials because traditionally these materials have been treated and materials such as galvanised steel is common for building and architectural reasons due to its strength and ease of use but its resilience to rust unlike the bare steel underneath.
However, many small applications exist too, coatings for components for optics and micro medical devices could be the size of a human hair. Whether very large, very small or somewhere in between, material choice and surface suitability can be very important factors and engineering these surfaces to be right for the application at hand requires knowledge of both the material and its inherent properties as well as the treatment processes and their properties.
Surface Treatment – Which Are We Talking About?
Surface treatments can be for almost any material and while there are classic treatments such as anodising and galvanising which have been common for metals for many years, there are a number of other techniques and here are a few reasons why you might use them.
| Treatment Technique | Materials | Reason For Using |
| Anodising – using an electrochemical process to create a strongly bound oxide layer. | Metals | Adding a strong top layer to the material protects it from corrosion, it can also add colour and be a good surface to adhere to. |
| Galvanizing – dipping a metal such as steel into a molten metal like zinc | Metals | Building up a protection layer of zinc protects from rust and galvanic protection from liquids. |
| Electroplating – a chemical deposition system using flow of materials to a charged surface to create a new surface. | Metals | Coating useful materials such as conductive copper onto useful core material. |
| Chemical Treatment – using different chemicals to react a material surface to something more useful. | Many materials | Reacting a material surface to create something new. Acid etching is a good example, but so is solvent vapour melting acrylic. |
| Heat Treatment – applying heat to a material to relax or change the molecular structure making it harder or more useful. | Mainly metals | Heat treatments can affect both the top surface and deeper depending on the intensity and power used. |
| Grit Blasting – removing the top layer of the material, exposing fresh clean material underneath and giving a larger surface area. | Many materials | Exposing fresh material and removing loose top contamination can be very powerful, it can also leave behind a nice finish. |
| Painting and Coating – adding a layer of paint or other coating to a material. This can be functional, visual or both. | Many materials | Painting is often visual but it protects at the same time. Other coatings could have a wide variety of reasons to be used from a liquid repellent to light absorption. |
| Plasma and Corona Treatment – electrical treatments to change material properties for improving | Many materials | Plasma and Corona clean a surface and then change it slightly at a molecular level. Imparting new chemistry that is good for bonding to. |
Keeping the majority of the material the same is often very important, it may be the case that a metal body panel requires a painted finish for protection and aesthetics, but retains its inherent strength. Equally, a part may require a treatment to adhere printing inks, but the polymer itself must be used to provide barrier properties or be non-reactive to stored drugs in the case of COC prefilled syringes.
With many applications and choices in engineering, the choice of which material, which process and which surface treatment will come down to investigation and preference. It’s unlikely any one material or process will tick every single box, but combining different techniques will hopefully give the finish and product required.
What Are The Advantages Of Surface Treatment?
Ability to use a variety of materials
Picking a material because it is rigid, flexible, easy to work with, resistant to chemicals or cheap to use are often key focus points. There are likely many points to consider when selecting materials and the material finish often doesn’t need to be at the top of the list, so long as it can be treated to give the properties required, the main focus should be on the bulk properties, cost or other important factors.
Design the product you want to design
Using the right material in the first place can open a lot of design concepts and allow for products to be made in the right way from the start. Rather than limiting your options and compromising with a material that has the right surface finish but isn’t quite right in other areas leading to design restraints. A surface treatment allows you to make the product you need and finish it as required.
Ability to work with other processes
Many surface finishes are for protection or only visual, but many are functional and aid in bringing together different processes. Adhesive bonding low surface energy or dissimilar materials is a key example of this as surface treatment can standardise the two materials allowing for strong and consistent bonding with an adhesive perhaps not designed for at least one of the surfaces.
Standardising manufacturing processes
Working with metals, polymers, glass, ceramics and other materials together can be tricky – one ink might work with glass, but not with plastics while another adhesive could bond with metals but peels off a ceramic easily. Giving all materials the same pretreatment can standardise production, especially when combined with automation which not only gives a standard result, but also improves repeatability and product quality – ultimately leading to a better product with less failures during its lifetime.
Plasma, Corona and Ozone Surface Treatments
As a company manufacturing plasma and corona treatment machines, along with ozone surface treatment, we have to have a little section about these technologies.
Their focus is for priming and preparing surfaces for adhesion and to create a usable, repeatable surface that performs well for inks, coatings and glue bonding.
The treatments have a number of other uses too, some will use them for surface cleaning and surface coating but the ultimate goal is often adhesion or simply wetting of liquids over the surface.
Plasma cleaning might be a method of using the technology used for other purposes, with many using plasma cleaning as a quick and liquid free way to clean a material. This might be combined with a further surface treatment such as coating that needed the super clean surface to ensure contamination isn’t trapped.
As with many surface treatments, it might be that Plasma and Corona make the right difference to your material and give the properties required, in many cases they don’t and another technique needs to be used. Evaluating the right materials with the right surface treatment and the right further processes will give you the confidence to create the products you want.
The biggest thing to remember is that they’re all tools to get the job done and using the right one at the right time will give you the right results!
