Aluminum surface hardening

Laser Hardening and Modification. Lasers are used to surface harden ductile steels and improve the toughness to a depth of 0.35 min or more. Lasers can also be used to bond solid or powder coatings to a surface. Typical coalings are nickel or titanium carbide on iron, and nickel, cobalt, manganese, and titanium carbide. TiC. on aluminum. I1 sc of lasers with other specialized coating methods is common. 

Several available FTIR techniques such as attenuated total reflection [5-7] have been utilized for coatings hardened on a metal surface, diffuse reflectance [8] for ultra-thin films, and transmittance [9, 10] for clear or transparent coatings. The FTIR is useful for determining parameters such as residual porosity and molecular bonding. If used in concert with a microscope, excellent spatial resolution can be obtained. Hasik et al. [11] studied a polysiloxane-silsesquioxane system with FTIR spectroscopy while developing SiCO ceramic. The authors noticed the transformation in vibration bands, in their material, as a function of chemical compositions and temperature. A quartz crystal microbalance and reflection-absorption infrared spectroscopy (RAIR) was used to study silane reaction over oxidized aluminum surface [12]. 

Materials with hard oxides, including stainless steels and aluminum and titanium alloys, are particularly susceptible to this form of attack. In steel, it is also known as false Brinelling because of the high surface hardness that can be created in work-hardening grades. 

One important class of particulate composites is dispersion-hardened alloys. These composites consist of a hard particle constituent in a softer metal matrix. The particle constituent seldom exceeds 3% by volume, and the particles are very small, below micrometer sizes. The characteristics of the particles largely control the property of the alloy, and a spacing of 0.2-0.3 tim between particles usually helps optimize properties. As particle size increases, less material is required to achieve the desired interparticle spacing. Refractory oxide particles are often used, although intermetallics such as AlFes also find use. Dispersion-hardened composites are formed in several ways, including surface oxidation of ultrafine metal powders, resulting in trapped metal oxide particles within the metal matrix. Metals of commercial interest for dispersion-hardened alloys include aluminum, nickel, and tungsten. 

In the manufacture of bonded insulating materials, the fibers in the fleece shaft or on the conveyor belt are sprayed with an aqueous binder, generally a phenol-formaldehyde resin. The binder content in the bonded insulating material is 3 to 4%. Compaction to the desired density and hardening of the resin binder occurs in a tunnel kiln, through which the fibers are continuously transported on a conveyor belt. The compaction is achieved with a second belt which exerts the required pressure on the upper surface of the continuous sheet. This is often followed by laminating the sheet with e.g. paper, aluminum or plastic foil. Finally the product is rolled up or cut into sheets. 

To illustrate the problem for the product developer, one only has to enumerate the soils and surfaces. The soils can vary from simple dust and hair to dirt, hard water spots, and fingerprints to hardened grease, soap scum, and excrement. Although the usual household cleaning tasks are concentrated in only two rooms of the house, kitchen and bathroom, the number of different surfaces encountered are many. In the U.S., for example, there may be Formica , ceramic tiles, grout, lacquered wood, vinyl flooring, painted surfaces, brass, stainless steel, enamel, porcelain, aluminum, chrome, glass, marble, methyl methacrylate, and other types of plastics. All of these materials may occur within only two rooms of the same home ... 

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