In a low pressure plasma system, the plasma generating device contains a vacuum chamber, generator, electrode and controls. A vacuum pump is used to reduce the pressure within the plasma chamber. The pressure within the vacuum plasma chamber is generally reduced to approximately 0.1-0.5 mbar. There is also usually a process gas drawn into the chamber to form the plasma, the type of gas depending on the desired plasma treatment and substrate material.
Low pressure plasma is always a batch process and has the advantage that all accessible surfaces are equally treated. Parts of any configuration can thus be effectively surface treated. For example, plasma can be used to plasma treat structural components, textiles and powders. Plasma systems may also be used to treat a variety of material types including polymers, metals, glass and ceramics. Research has even been conducted regarding plasma treatment of biological materials such as bird feathers.
Plasma treatment can be used to achieve numerous surface modification objectives. Plasma activation of a surface to make it more adhesive is most commonly achieved by treatment with oxygen as the process gas. Surface activation increases the surface energy of the substrate increasing it’s wettability and adhesiveness. Surface oxide reduction can often be achieved with hydrogen as the process gas. Polymer surfaces can also be rendered hydrophobic using fluorine containing process gases such as sulfur hexafluoride. There are many possibilities available to suit an infinite number of surface treatment objectives.
Plasma treatment systems can also be configured to process numerous part dimensions and throughput objectives. Plasma systems range in size from bench top scale to 3,000+ gallon capacity units able to treat hundreds of square feet per batch. Due to the highly variable system requirements, units can be customized to most efficiently meet any surface modification objective.