Bond glass/metal

Loctite Glass Bonding Adhesive 350 1 part - base unknown High optical clarity glass bonding. Glass metals UV 120 365... 

Formulations (clear liquids or coloured formulations) based on an ethanol solution of various silica or aluminosilica precursors are marketed for application on glass, metallic or plastic surfaces to achieve hard 1 10 pm coatings that form strong chemical bonding with the surfaces and protect against staining or water corrosion. 

Although acid-base effects can be important in adhesion our studies indicate that bonding to metals through silane coupling agents is not by an acid-base mechanism, but probably through Si-O-M oxane bonds. As with glass, the hydrolysis and formation of oxane bonds are true equilibria, but the individual equilibrium constants are not known. 

Reference was made earlier to difficulties of wetting plastics surfaces, and to problems in this regard compared with hydrophilic materials like glass, metals, and timber. With some plastics very effective bonds are possible, but as a group, mainly for this reason, they are amongst the most difficult to join by adhesives. 

Epoxy-phenolic adhesives were developed primarily for bonding metal joints in high-temperature applications. Their first major application was to join major aircraft components. They are also commonly used for bonding glass, ceramics, and phenolic composites. Because of their relatively good flow properties, epoxy phenolics are also used for bonding honeycomb sandwich composites. 

Figure 9.5. A schematic representation of glass/metal interactions (a) a simple non-reactive oxide glass/metal interface across which only van der Waals interactions are developed (b) a more intense interaction between the metal and the oxide glass is developed by the presence of an adsorption layer with a typical thickness of 1 nm that is rich in oxygen (c) improved wetting and bonding produced by preoxidation or in situ oxidation of the metal that leads to the creation of a glass/MO interface.

Silanes have been used in sealants since the early 1960s when they were introduced successfully in polysulfide formulations. It was found that only small amounts of silane were needed in the formulation to improve adhesion to surfaces such as glass, metals, and, in some cases, concrete without using a primer. More recently, hybrid sealants (made of an organic polymer backbone and a silane crosslinker) have been widely commercialized. Many of these hybrid sealants have superior properties and will bond to a variety of substrates. 

The most widely used applications reported in 1973 included rib structures in the fabrication of lightweight reinforced-plastic parts and as a core material in sandwich construction, bonded to metal, wood, or glass. Other applications are as reinforcements for aircraft-control surfaces, radome housings, fUler blocks under fuel cells, tank floats for indicating devices, and ribs, posts, and framing in houses and shelters. Due to its buoyancy characteristics cellulose acetate foam has been used in lifeboats, buoys, and other flotation devices (21). 

Heating Si02 ruptures Si-0 bonds, enabling metal ions to form ionic bonds with some of the 0 atoms. The nature of the glass depends on the metal added. 

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