Adhesion mechanical

Wear. Ceramics generally exhibit excellent wear properties. Wear is deterrnined by a ceramic s friction and adhesion behavior, and occurs by two mechanisms adhesive wear and abrasive wear (43). Adhesive wear occurs when interfacial adhesion produces a localized Kj when the body on one side of the interface is moved relative to the other. If the strength of either of the materials is lower than the interfacial shear strength, fracture occurs. Lubricants (see Lubricants and lubrication) minimize adhesion between adj acent surfaces by providing an interlayer that shears easily. Abrasive wear occurs when one material is softer than the other. Particles originating in the harder material are introduced into the interface between the two materials and plow into and remove material from the softer material (52). Hard particles from extrinsic sources can also cause abrasive wear, and wear may occur in both of the materials depending on the hardness of the particle. 

Combination of Eq. 7 or Eq. 8 with the Young-Dupre equation, Eq. 3, suggests that the mechanical work of separation (and perhaps also the mechanical adhesive interface strength) should be proportional to (I -fcos6l) in any series of tests where other factors are kept constant, and in which the contact angle is finite. This has indeed often been found to be the case, as documented in an extensive review by Mittal [31], from which a few results are shown in Fig. 5. Other important studies have also shown a direct relationship between practical and thermodynamic adhesion, but a discussion of these will be deferred until later. It would appear that a useful criterion for maximizing practical adhesion would be the maximization of the thermodynamic work of adhesion, but this turns out to be a serious over-simplification. There are numerous instances in which practical adhesion is found not to correlate with the work of adhesion at ail, and sometimes to correlate inversely with it. There are various explanations for such discrepancies, as discussed below. 

In the adsorption mechanism, adhesion is modeled as occurring across a well-defined interface by molecular interaction across that interface, and is often... 

McBain and Hopkins [2], in their classical scientific study, argued that the surface roughness of a porous material was the basis of mechanical adhesion , its being... 

Packham, D.E. and Johnston, C., Mechanical adhesion were McBain and Hopkins right An empirical study. Ini. J. Adhes. Adhes., 14(2), 131-135 (1994). 

Mechanical adhesion. Mechanical interlocking between the two substrates can also contribute to adhesion. This mechanism would function most effectively with fibers with rough surfaces and irregular or non-circular cross-sectional shapes. 

Condition in which two surfaces are bonded together by interfacial forces caused by valence forces or interlocking forces or both (see mechanical adhesion and specific adhesion). 

Mechanical adhesion. Cracks and pits are produced on the treated rubber surface which favor the mechanical interlocking with the adhesive. Eurthermore, unreacted solid prismatic TCI crystals on the treated rubber surface can be dissolved by the organic solvent into the adhesive, favoring the reaction with the adhesive. 

Other explanations of the nature of the polymer to metal bond include mechanical adhesion due to microscopic physical interlocking of the two faces, chemical bonding due to acid/base reactions occuring at the interface, hydrogen bonding at the interface, and electrostatic forces built up between the metal face and the dielectric polymer. It is reasonable to assume that all of these kinds of interactions, to one degree or another, are needed to explain the failure of adhesion in the cathodic delamination process. 

Growth mechanism adhesive-type two-dimensional nucleation growth or spiral growth ... 

Additional work must be completed before these hydration inhibitor treatments will be widely used. However, it appears that combined FPL/inhibitor pretreatments have the potential of producing water stable aluminum oxides with structures that promote mechanical aspects of adhesion in a relatively simple manner. Since mechanical adhesion mechanisms are not greatly affected by water, these pretreatments show promise as a means of increasing the durability of metal/polymer adhesion systems in wet environments. 

The type of adhesion dealt with in the examples in the second paragraph above and Fig. 1 is mechanical or structural while for the lithographic resist adhesion requirements described in this paper a more practical definition of adhesion, one first proposed by Mittal [16], is being referenced and used. Resist patterning layer-substrate adhesion is required only to process or pattern a particular device layer. After the circuit layer is patterned, the resist layer is removed and does not become an integral part of the circuit, as opposed to a PI interlevel metal dielectric layer which does. As such, it is not required to possess high mechanical adhesion strength. In fact, the resist layer must be quantitatively removed after the circuit required layer has been patterned. If the resist layer adheres too well and becomes difficult to remove, it actually interferes with successful circuit fabrication. 

Percussion is a repetitive solid body impact, such as experienced by print hammers in high-speed electromechanical applications and high asperities of the surfaces in a gas bearing. Repeated impacts result in progressive loss of solid material. Percussive wear occurs by hybrid wear mechanisms, which combine several of the following mechanisms adhesive, abrasive, surface fatigue, fracture, and tribochemical wear.75... 

This phenomenon is described by Arslanov and al(9) as the mechanical adhesion. The aluminum should be, in this theory, linked in the pores of the PET. So, an augmentation of the specific surface of the polymer leads to an increase of the adhesion of the aluminum film evaporated onto the polymer. 

Despite their great technical importance, there are few reported studies of segregation at solid metal/oxide interfaces. Hondros (1978) used Auger spectroscopy to examine interfaces formed between sapphire and Fe containing Cr or Ni and found a high interfacial enrichment of Cr over a zone of a few nanometers. The results were used to explain the strong mechanical adhesion of Fe on A1203 induced by Cr additions. 

Adhesion, laminates, fracture mechanics, adhesive fracture toughness, polymers, metal substrates, T-peel, fixed arm peel... 

Adhesion is a complex phenomenon based on a number of different mechanisms. In contrast to simple mechanical adhesion, silanes enable a sealant to bond chemically to a substrate, resulting in more durable adhesion. The bond is less susceptible to the negative effects of moisture and temperature. The nature of the substrate surface also plays an important role in achieving good adhesion. The more chemically active sites (preferably hydroxyl groups) the substrate has, the... 

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