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Fundamentals of Plasma Polishing
Published in V. K. Jain, Advanced Machining Science, 2023
Hari Narayan Singh Yadav, Manjesh Kumar, Manas Das
Plasma naturally exists and can also be produced in industry or a laboratory, which offers openings for different uses, featuring electronics, thermonuclear chemistry, fluorescent lamps, and lasers, etc. To be more precise, plasma technologies are used in the manufacture of the majority of computer and mobile phone parts. Plasma has three main characteristics that make it appealing for use in chemistry and related fields: (1) The temperature of at least some plasma components and energy density can significantly exceed those in conventional chemical technology, (2) plasma have the ability to generate extremely large quantities of energetically and chemically active entities (e.g., ions, electron, atom, radicals, and various wavelength photons), and (3) plasma systems allow exceptionally large quantities of chemically active species while maintaining the bulk temperature as low as normal room temperature. These plasma properties allow substantial escalation of conventional chemical procedures and improvement in their performance. The plasma polishing process has made huge advances in the field of surface modification [27].
Plasma in Nature, in the Laboratory, and in Industry
Published in Alexander Fridman, Lawrence A. Kennedy, Plasma Physics and Engineering, 2021
Alexander Fridman, Lawrence A. Kennedy
Plasmas offer two main characteristics for practical applications. First, they can have temperatures and energy densities greater than those produced by ordinary chemical means. Second, plasmas are able to produce, even at low temperatures, energetic species that can initiate chemicals reactions that are difficult or impossible to obtain using ordinary chemical mechanisms. The energetic species generated cover a wide spectrum of such species, for example, charged particles including electrons, ions, and radicals, highly reactive neutral species such as reactive atoms (e.g., O, F, etc.), excited atomic states, reactive molecular fragments, and different wavelength photons. Plasmas can also initiate physical changes in material surfaces. Applications of plasma can provide major benefits over existing methods. Often processes can be performed that are not possible in any other manner. Plasma can provide an efficiency increase in processing methods and often can reduce the environmental impact when compared to more conventional processes.
The Use of Microwaves, Plasma and Laser for Wood Modification
Published in Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones, Wood Modification Technologies, 2021
Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones
There are two types of plasma: low pressure plasma and atmospheric plasma. Low pressure plasma is a small amount of gas in a vacuum chamber that is activated by a radio frequency. Energyrichions and electrons are created together with other reactive particles that make up the plasma which can have be used in three ways: in micro sand blasting using ion bombardment, in chemical reactions, where ionised gas reacts chemically with the surface, and in UV radiation that breaks down long, complex carbon chain compounds. In atmospheric plasma technology, a gas (air) flows through a nozzle at atmospheric pressure and is affected by a high voltage so that a plasma ignites. The gas turns on as plasma flows out of the nozzle. The atmospheric plasma has two different effects: activation and precision cleaning, which takes place through the reactive particles in the plasma, any loosely adherent particles being removed from the surface to be washed/activated by means of the compressed gas, which gives an active gas jet.
UHMWPE textiles and composites
Published in Textile Progress, 2022
Ashraf Nawaz Khan, Mohit Gupta, Puneet Mahajan, Apurba Das, R. Alagirusamy
The surface adhesion of the UHMWPE fibre can be improved through plasma treatment at atmospheric pressure by making the surface rough and introducing polar groups. It is reported that compared to the chemical treatment, the plasma-treated sample shows more improvement in the adhesion to the epoxy due to the enhanced mechanical keying. Plasma treatment of the material is an important technique used in many areas such as electronics, aerospace, automotive textiles, and the biomedical industries because of its ability to induce surface modification such as etching, deposition, and polymerisation (Jiang et al., 2009). Oosterom, Ahmed, Poulis, and Bersee (2006) investigated the adhesion performance of the UHMWPE fibres after different surface modification techniques. The three-gas phase surface modification technique (as listed in Table 22) such as UV/ozone, corona discharge, and radio-frequency, glow-discharge plasma as well as abrasion was investigated. The corona and the glow discharge technique were found to be effective due to activation of the surface with an increase in 100% surface energy in less than a minute, whilst the UV/ozone technique required more than a minute of exposure time through which it could achieve comparable surface modification with the other two techniques. Also, abrasion led to an increase in the adhesion property. However, the combined use of the discussed techniques certainly results in the best improvements in the adhesion property together with improvement in the ultimate shear strength of the UHMWPE/PMMA system.
Effect of high-voltage pulse bias on the stress and morphology of CA-PVD TiN coatings
Published in Surface Engineering, 2020
Golnaz Taghavi Pourian Azar, Mustafa Ürgen
Cathodic arc physical vapour deposition (CA-PVD) is widely applied for deposition of nitride-based coatings. The primary advantage of this method is its ability to produce highly ionised plasma. Ion energies of CA-PVD plasma can be further increased or tuned by applying a negative bias applied to the substrate. Application of a DC bias during deposition leads to the formation of dense and well-adherent coatings. However, this application increases residual compressive stresses of the coatings that may be detrimental for some applications [2,4]. On the other hand, it is well known from filtered CA systems that using HVPB introduces an opportunity to control stress build-up of nitride-based coatings [5,6]. Recently, we have adapted this method to unfiltered cathodic arc systems and observed similar preferred orientation changes as seen in the filtered arc systems [6,7]. We also determined the critical role of Ar presence in the gas mixture in these changes [8].
Efficacy of cavity liners with/without atmospheric cold helium plasma jet for dentin remineralization
Published in Biomaterial Investigations in Dentistry, 2020
Hamid Kermanshah, Reza Saeedi, Elham Ahmadi, Ladan Ranjbar Omrani
Plasma is the 4th state of matters that forms at very high temperatures. This ionized gas includes photons, electrons, positive and negative ions, atoms, free radicals, and excited and non-excited molecules that constantly interact with each other [11]. Plasma has different types including hot, warm and cold plasma. The cold plasma is a type of plasma created by electrical discharge [12]. Of different methods of production of cold plasma, plasma jet has gained attention since it is portable, can be charged on spot and has low energy consumption. The ACPJ has low temperature (room temperature) and therefore, has several medical applications [13]. Researchers have shown that plasma surface modification is a clean and effective method [10]. Its effect is related to plasma reactive species. According to the plasma type, the plasma gas reacts with the surface of substrates and creates new surface characteristics [10]. Increased wettability, as well as permeability, is among the modifications caused by argon and helium plasma in dental substrates [10].