Glass corrosion properties

XPS has been used in almost every area in which the properties of surfaces are important. The most prominent areas can be deduced from conferences on surface analysis, especially from ECASIA, which is held every two years. These areas are adhesion, biomaterials, catalysis, ceramics and glasses, corrosion, environmental problems, magnetic materials, metals, micro- and optoelectronics, nanomaterials, polymers and composite materials, superconductors, thin films and coatings, and tribology and wear. The contributions to these conferences are also representative of actual surface-analytical problems and studies [2.33 a,b]. A few examples from the areas mentioned above are given below more comprehensive discussions of the applications of XPS are given elsewhere [1.1,1.3-1.9, 2.34—2.39]. 

General corrosion properties The glass surface may react with a corrosive agent in one or a combination of the following ways ... 

Enhanced anti-corrosion properties are also reportedly achieved by mill additions of lithium titanate, lithium aluminate or magnesium titanate to the host glass frit . 

A typical batch reactor (Figure 8.1) will be made of stainless steel or glass-lined steel. Stainless steel vessels have better heat transfer characteristics than their glass-lined counterparts and a wider array of reactor internals are available. Glass-lined vessels, on the other hand, can offer superior fouling or corrosion properties and are often used for reactions... 

CHEMICAL PROPERTIES stable under ordinary conditions of use and storage hydrolyzes slowly in water to telluric acid (H606Te) more quickly hydrolyzed by aqueous potassium hydroxide when pure, does not attack glass corrosive to mercury not as chemically inert as sulfur hexafluoride (SF(,) and selenium hexafluoride (SeFs) because the maximum covalence of tellurium is greater than six FP (NA) LFLZUFL(NA) AT(NA) HC(NA) HF(-1318.0 kJ/mol gas at 25 C) Tc (83 C, 181.4 ). 

The most widely used epoxy resins are reaction products of either bisphenol A or a novolac phenolic resin with epichlorhydrin. When used to manufacture corrosion-resistant structures for use in the chemical process industry, epoxy resins are generally hardened with either aromatic or cycloaliphatic amines. The hardeners for epoxy resins are, with few exceptions, added at levels varying from 20phr (parts per hundred resin) to lOOphr. This means that the hardener is actually quite a high proportion of the matrix resin and has quite a profound effect on the mechanical and corrosion properties of the cured resin. Thus the selection of the most suitable hardener is critical to the eventual success of the application. Epoxy resins have viscosities of several thousand mPas at room temperature, which makes it much more difficult to wet out glass fibre efficiently with them than with polyesters. Wet-out therefore involves heating the resin formulation to between 40°C and 60°C to reduce the viscosity to less than 1000 mPas. 

Properties Colorless gas often bluish due to impurities m.w. 49.00 dens. 1.32 (liq.), 1.72 (solid) f.p. -132 C b.p. -60 C Toxicology Toxic by Inh. poison severe irritant to skin, eyes, and mucous membranes Precaution Vigorous reaction with glass corrosive to quartz explosive reaction with alkenes oxygen difluoride incandescent... 

Throughout the processing and service lifetime of the majority of glasses they are exposed to a wide variety of corrosive environments, many of which are aqueous based. Therefore, their surface properties as a function of aqueous corrosion are of both importance and significant interest. Glass corrosion induces transformations in the following three broad, albeit related categories ... 

Torp, S., Arvesen, R. Influence of Glass Fiber Quality on Mechanical and Strain Corrosion Properties of FRP - Proposed Method for Quality Control, Proceedings of the 34th Annual Conference, RP/CI, SPl, Section 13-D, 1979... 

It is particularly important that all types of fuel samples, which pass a low-tarnish strip classification, be collected in clean, dark glass bottles, plastic bottles, or other suitable containers that will not affect the corrosive properties of the fuel, Avoid the use of tin plate containers for collection of samples, since experience has shown that they may contribute to the corrosiveness of the sample. 

Corrosion Resistant Fiber-Reinforced Plastic (FRP). Fiber glass reinforcement bonded with furfuryl alcohol thermosetting resias provides plastics with unique properties. Excellent resistance to corrosion and heat distortion coupled with low flame spread and low smoke emission are characteristics that make them valuable as laminating resins with fiber glass (75,76). Another valuable property of furan FRP is its strength at elevated temperature. Hand-layup, spray-up, and filament-win ding techniques are employed to produce an array of corrosion-resistant equipment, pipes, tanks, vats, ducts, scmbbers, stacks, and reaction vessels for industrial appHcations throughout the world. 

Flame-Retardant Resins. Flame-retardant resins are formulated to conform to fire safety specifications developed for constmction as well as marine and electrical appHcations. Resins produced from halogenated intermediates (Table 5) are usually processed at lower temperatures (180°C) to prevent excessive discoloration. Dibromoneopentyl glycol [3296-90-0] (DBNPG) also requires glass-lined equipment due to its corrosive nature. Tetrabromophthahc anhydride (TBPA) and chlorendic anhydride (8) are formulated with ethylene glycols to maximize fiame-retardant properties reaction cycle times are about 12 h. Resins are also produced commercially by the in situ bromination of polyester resins derived from tetrahydrophthahc anhydride... 

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