Surface treatment process

Oxidative surface treatment processes can be gaseous, ie, air, carbon dioxide, and ozone Hquid, ie, sodium hypochlorite, and nitric acid or electrolytic with the fiber serving as the anode within an electrolytic bath containing sodium carbonate, nitric acid, ammonium nitrate, ammonium sulfate, or other electrolyte. Examples of electrolytic processes are described in the patent Hterature (39,40)... 

For a surface treatment process to be practical, not only does it have to produce a clean, stable surface suitable for chemical or physical bonding to the... 

Other plant-scale applications to pollution control include the flotation of suspended sewage particles by depressurizing so as to release dissolved air [Jenkins, Scherfig, and Eckhoff, Applications of Adsorptive Bubble Separation Techniques to Wastewater Treatment, in Lemlich (ed.). Adsorptive Bubble Separation Techniques, Academic, New York, 1972, chap. 14 and Richter, Internat. Chem. Eng, 16,614 (1976)]. Dissolved-air flotation is also employed in treating waste-water from pulp and paper mills [Coertze, Prog. Water TechnoL, 10, 449(1978) and Severeid, TAPPl 62(2), 61, 1979]. In addition, there is the flotation, with electrolytically released bubbles [Chambers and Cottrell, Chem. Eng, 83(16), 95 (1976)], of oily iron dust [Ellwood, Chem. Eng, 75(16), 82 (1968)] and of a variety of wastes from surface-treatment processes at the maintenance and overhaul base of an airline [Roth and Ferguson, Desalination, 23, 49 (1977)]. 

When the photostabilization of a polymer material is to be obtained through such a surface treatment process, it is all important to make sure that the protective effect will last throughout the service life and therefore to ensure a long-term adhesion of the coating onto the substrate. This can be best achieved by promoting a grafting reaction between the two elements (20). For that purpose, the photoinitiator was partly incorporated in the top layer of the PVC plate by a surface treatment with an acetone solution. Upon UV-irradiation of the resin-coated sample, the following reactions are expected to occur ... 

Foundry Activities (Casting) Surface Surface Treatment Process Chemical Coaling... 

Optimal joints can generally be fabricated by the correct combination of epoxy adhesive formulation (i.e., type of resin, curing agent, fillers, modifiers) and surface treatment process. 

Because of their excellent chemical resistance, polyolefins are impossible to join by solvent cementing. Because of their very low surface energy, polyolefins can only be adhesively bonded after surface treatment processes. The most common way of joining polyolefins is by thermal welding techniques. 

Code used in parentheses indicated the surface treatment process code used without parentheses indicates coating process. 

Electroplating is the most widely used electrochemical surface treatment process, involving the electrochemical deposition of a layer of metal or alloy onto a substrate by means of one or more cathodic metal ion reduction reactions of the form... 

Polyethylene, as LDPE, LLDPE or a mixture or blend involving combinations of LDPE, MDPE, HDPE, EVA, etc., finds a wide usage in bags, sacks, sachets, overwraps, shrink wraps, stretch wraps, etc. Most deep freeze packs, for example, use LDPE or an LDPE mixture which is produced from a reel on a form fill seal type machine. However, as many of these packs are up to 100% printed, even ink of 2-5 Pm could be considered as a separate layer which modifies some of the physical and chemical properties. As all polyolefins need a surface (oxidative) treatment to ensure a good print key, this or any other surface treatment process may further modify the film properties. 

Develop surface treatment processing to minimize the contact resistance between the sensing layer and the underlying metal contact... 

Hydrogen reduction of oxides as well as gasification reactions, solid-state synthesis, and surface treatment processes can be focused on a thin layer of a flat surface and stimulated by non-thermal plasma (Te > To). Similar to the powder-related cold plasma processes, thin-layer processes in cold gas can also be limited by surface temperature. Again, VT nonequilibrium (Te > Tv > To) in this case can provide surface temperatures (Tg) significantly exceeding the gas temperatme (To), because surface VT relaxation is much faster than that in the gas phase. The non-equilibrium heating of a thin layer can be accomplished by... 

Cr207 " dichromates are usually employed in surface treatment processes. Cr is highly toxic and its elimination from aqueous effluents is crucial. By applying the previous removal method based on nickel particles and hydrogen, the reaction should be described by the following equation ... 

B. Veeraraghavan, D. Slavkov, S. Prabhu, M. Nicholson, B. Haran, B. Popov, B. Heimann, Synthesis and characterization of novel non-chrome electrolytic surface treatment process to protect zinc coatings, Surf. Coat. Techol. 167 (2003) 41—51. 

To enhance the adhesive strength, the surface properties of substrate are very important. The surface treatments are often used to enhance the adhesive strength between the coating and the substrate, as well as to enhance the surface energy of substrate - improving wettability of coating. If adhesive problem occurs, check out the surface treatment processes such as flame, plasma, or corona. Corona treatment does not persist permanently, therefore it should be done in-line, the corona is often applied directly before the coating station. 

Some materials can create particular problems for surface preparation and for obtaining adequate adhesion, and so should be avoided if possible. Bonds to metal alloys and plastics have been well researched, and a number of procedures are documented. Bonds to cementitious and siliceous surfaces are also readily obtainable, although little is really known about optimising surface treatment processes for maximum adhesion. Regard should be paid to the dusty, friable nature of concrete surfaces, as well as its high alkalinity. 

Surface potential difference. Absorbed layers of contamination on metallic surfaces can be detected by measurement of variations in the amount of energy required for an electron to leave the surface. The Fokker Contamination Tester developed from this principle is claimed to be very useful in the optimization of various surface treatment processes and routine quality control activities (6). 

Table 3.1 shows a list of surface treatment processes for metallic and non-metallic substrates and the main effect of each treatment procedure on the material surface. 

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