Substrate cracks

A silicone rubber adhesive layer is used in US-A-4081819 to bond an HgCdTe substrate, which includes an epitaxial layer, to a second substrate. The silicone rubber adhesive reduces the risk that the substrate cracks when cooled to cryogenic temperatures. 

This also means that stress relief joints will be required on this type of floor to break the lines of stress from the slow growth of the brick or tile, and so prevent disbonding, followed by heaving, just as the stress relief joints in a monolithic floor provide for the cure shrinkage of the monolithic. It should also be remembered that, unlike brick on a membrane, if brick (or tile) are bonded to the substrate, and if the substrate cracks, so will the tile or brick structure. 

Protection layer of the photoresist is essential in this technological chain. If this layer is not used, the membranes of silicon dioxide would crack due to internal stress after being released from the substrate. Cracking the membranes results in a breaking on the cantilevers and brings technological yield close to zero. 

The glass transition temperature (T ) affects adhesion, flaking, and peeling from the substrate, crack formation, and resistance to impact shock [2.44]. In acrylates adjustment of is achieved relatively easily e.g. via the ratio of methyl methacrylate... 

Delamination may be complete or partial. Complete delamination results in gross separation of the device, substrate, or other adherend. Partial debonding can result in device or substrate cracking with complete detachment occurring in time. Numerous factors and mechanisms contribute to delamination, some of which are as follows ... 

The effect of plasma electrolytic oxidation (PEO) treatment on the SCC of surface-modified magnesium alloys was studied [167]. PEO coating offered improved corrosion resistance. However, the barrier film did not improve the SCC resistance in ASTM D 1384 test solution. The SCC of PEO-coated specimens was attributed to the development of micro cracks in the coating, leading to substrate cracking under SSRT test conditions [167]. 

Good resistance to freeze-thaw cycles and to chemical attack due to high density and very low permeability was also obtained. Carbonation and chloride ions penetration are strongly decreased. Layers of thickness over 12 mm exhibited sufficient strength and ductility to bridge and waterproof the substrate cracks. Increased adhesion to substrate material, that is, old concrete, was excellent provided that the surface was cleaned and wetted. The adhesion was tested using tensile and shear bond specimens. 

Fig. 4.42. Schematic diagram of steady advance of a tunnel crack in a strained layer embedded between two relatively thick substrates. Crack growth is driven by residual stress in the buried layer.

Fig. 7.5 Comparison of GMOD failure modes for coatings on clear substrates. Cracking (solid symbols) is a later failure mode compared with adhesion (open symbols). In this graph, the lines are drawn to guide the eye and do not represent fit equations to the data (Note Test results. Actual...

In the above analyses, we have only considered interfacial fracture. Several other cracking patterns have been observed in coated systems subject to residual stresses. The more common examples include coating surface cracks (Fig. 13), coating channelling cracks (Fig. 14), substrate cracks (Fig. 15), and spalling... 

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