In last week’s blog post, Using Plasma for Surface Cleaning and Activation Rose Roberts, Ph.D., Senior Custom Applications and Materials Engineer, discussed how to use plasma for the dual purposes of cleaning critical surfaces and activating critical surfaces as they are prepared for bonding, coating, sealing, painting, or printing. In this week’s post, she will provide tips regarding how to enhance plasma use at your site.
In this next section, Rose describes the importance of understanding upstream processes that impact the surface that you’re going to treat with plasma. Important considerations include the chemical composition of upstream contaminants as well as the level of soil that may be on the surface. Let’s see what Rose has to say:
Plasma equipment is often used with different types of gas for surface activation. Determining which type of gas to use depends on the surface treatment outcome that is needed. For example, compressed air and argon are two types of gas that might be used for plasma treatment. Oxygen is the workhorse component of most plasma processes, and compressed air is an inexpensive way to get oxygen into a process. When excited and/or ionized in a plasma, oxygen will oxidize organic materials present on inorganic surfaces (metals, ceramics, glasses) to CO2 and H2O, allowing them to be pumped away. On organic surfaces, oxygen-containing plasmas can partially oxidize the surface to create polar organic groups such as hydroxyls and carboxylates. Surfaces oxidized this way can show greatly enhanced adhesion to paints, coatings, and adhesives.
As argon is an inert gas with little to no chemical reactivity (even when excited or ionized in a plasma), it can be of limited utility when the desired outcome is chemical activation or contaminant removal. However, in combination with a reducing gas (generally a hydrogen source like hydrogen, acetylene or methane), the surface bombardment of the heavy argon ions will dehydroxylate and reduce oxide thickness while increasing the oxide density. This improves the corrosion resistance of aluminum and ferric materials and enhances the performance of barrier coatings.
At BTG Labs, we have equipped our Surface Lab with four different types of plasma units. These units, listed below in ascending levels of power, include:
Let’s watch as Rose describes each of these units:
As noted above, each plasma treatment solution needs to be designed to match each particular application. For example, for vacuum plasma processes, the following parameters all affect the outcome and need to be controlled:
Atmospheric plasma treatment typically has fewer parameters to control than vacuum plasma. A few atmospheric plasma parameters to keep in mind include:
When implementing plasma treatment into manufacturing operations, it is important to understand whether the plasma treatment is achieving the intended goal. An objective method to quantify the effectiveness of the plasma treatments is required.
Digital surface inspection equipment provides rapid water contact angle (WCA) measurements that equip businesses with an objective, quantifiable method for determining the chemical cleanliness and consistency of the top few molecular layers of a surface. This makes WCA measurements ideal for confirming the state of your surface both prior to and after treatment. This allows for adjustment of parameters like the duration and power of plasma treatment to make sure the intended outcomes of your plasma treatment are achieved. WCA data also helps ensure that plasma equipment is running at peak performance - which helps protect investments in plasma equipment. This type of digital surface inspection equipment provides immediate access to meaningful data about material surfaces and allows full control of plasma treatment processes.
BTG Labs is committed to helping customers identify the root causes for challenges they face when cleaning and activating critical surfaces as they are prepared for bonding, coating, sealing, painting, or printing. We have a variety of ways that we serve our customers -- whether we visit you on-site, video conference with you, analyze samples you submit to us or have you as a guest in our lab, we will work relentlessly to help you mitigate any cleaning, coating, or adhesive bonding issues you are experiencing. We have invested in such a wide range of plasma equipment so that we can:
Our customized solutions also include helping manufacturers develop and implement new critical processes to control surface quality. Our lab equipment, combined with innovative digital surface inspection equipment, helps manufacturers choose the right plasma units for their needs. Our experienced Material Scientists can help customers optimize the parameters of the unit and design processes to monitor the unit’s ongoing performance.
Sometimes it can be challenging to duplicate the outcome of a plasma process at a different facility. One source of this variability can be seemingly minor differences in equipment between one lab and another. This variability can come from:
In these instances, we rely on digital surface inspection equipment and other surface analysis instruments such as X-ray Photoelectron Spectroscopy (XPS) to help us understand and mitigate the differences between different pieces of equipment.
Stay tuned to our blog for upcoming articles explaining additional equipment we have in our Surface Lab that will provide you with the support you need to optimize your manufacturing processes.
Would you like to learn more about how we can help you optimize your equipment and processes? Check out our Consulting Services page.
If you would like to learn more about how manufacturers are leveraging contact angle data to control their manufacturing processes, download the eBook: BTG Lab's Guide to Adhesion Science for Flawless Manufacturing, or click the image below: