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Cold Atmospheric Plasma Treatment to Enhance Joining Processes

Project Code: TBC


  • Determine the potential of CAP to enhance current industrial processes in a wide range of applications
  • Demonstrate one or more CAP optimised processes with supporting data and an understanding of at least some of the underlying science
  • Generate income through the incorporation of CAP into three or more project activities (SCP, JIP or Collaborative)

Project Outline

It is proposed that the capabilities of CAP processing are explored over a number of technologies within TWI to determine which could benefit significantly. It is known that plasma can do the following:

  • Cleaning (removal of hydrocarbons and other surface contamination)
  • Oxidation (using oxygen rich plasma)
  • Reduction (using hydrogen rich plasma)
  • Functionalisation (using active species in the plasma including OH, CO etc)
  • Chemical modification (eg breaking of C-C backbone, removal of  species such as F or Cl)
  • Chemical addition (eg addition of F to hydrocarbon backbone to create low energy surfaces)

Additionally CAP offers the benefits of being truly low temperature and therefore can be applied to thermally sensitive materials such as coatings and fabrics.

It is believed that all of the above capabilities could offer opportunities and benefits to members, not just for pre-treatment of materials for adhesive bonding but also for coating, thermal spraying, diffusion bonding (polymers), welding (polymers and metals), defunctionalisation of coatings (lithography), treatment of fabrics etc.

The work will compose of two distinct phases which in turn may create additional opportunities.

Phase I – Identification and initial investigation of the uses and effects of plasma within a range of joining and material preparation technologies

Phase II – Case study - Determination of the effect of CAP processing for industrial application

Relevant Industry Sectors

Technical and Economic Benefits

Plasma, often termed the forth state of matter, is seeing an increasing use within a wide range of industrial sectors for a number of applications. In particular it is used as an extremely effective method to clean or prepare surfaces for coating or bonding. One of its earliest uses was within the microelectronics sector where plasma treatment was and still is used to maintain high levels of cleanliness during the chip fabrication and coating processes. Indeed, it has also been used as a means of etching surfaces for micro lithography. More recently with the advent of atmospheric plasma, commercial treatments have been developed for the preparation of polymeric materials for adhesive bonding, a good example being the bonding of automotive light clusters where the plasma torch precedes the adhesive dispensing nozzle within a fully automated process.

The benefits of using plasma are significant including the fact that it is:

  • A non-contact process, thereby eliminating direct contamination
  • Fast (seconds vs minutes/hours for traditional wet/abrasive treatments)
  • Dry (no liquid chemistry or drying requirements)
  • Low energy (equipment can be as low as a few watts vs energy required to heat chemical solutions and dry substrates)
  • A safe process (few if any hazardous chemicals and associated handling and disposal issues)
  • A green process (little or no requirement for waste disposal)
  • Flexible (can be delivered either in automated form or manually and is scalable)

All of these benefits are of great interest to industry as plasma treatment offers significant savings in time, energy and cost without the sacrifice in quality.

Ongoing literature monitoring of the technology has shown an increasing trend for plasma processing and pre-treatments, especially in the areas of metal bonding and coating. It would therefore seem apparent that industrial demand for this process is only going to increase. The mechanism of CAP and other plasma systems is complex to understand and whilst it can be used empirically, there are obvious benefits to optimising the process according to substrate which requires further research.

For more information please email: