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The scrape adhesion test measures the determination of the adhesion of organic coatings when applied to smooth, flat panel surfaces. It is helpful in giving relative ratings for a number of coated panels showing significant differences in adhesion. The tested materials are applied uniformly to flat panels, mainly some sort of sheet metal.
Adhesives commonly react with oxygen at low temperatures, which leads to a slow break down of polymer chains. The breakdown of polymer chains is often undetectable until the adhesive has reached a critical point where the stability of remainder of the adhesive rapidly degrades. [1]
Note 1: Adhesion requires energy that can come from chemical and/or physical linkages, the latter being reversible when enough energy is applied. Note 2: In biology, adhesion reflects the behavior of cells shortly after contact to the surface. Note 3: In surgery, adhesion is used when two tissues fuse unexpectedly. [1]
The Iosipescu test requires special equipment in addition to the roller setup already used for other three-and four-point flexural tests. [22] ASTM C1469 outlines a standard for AFPB testing of advanced ceramic joints, and the method has been proposed to be adapted for use with continuous ceramic matrix composites.
The stress intensity factor at the crack tip of a compact tension specimen is [4] = [() / / + / / + /] where is the applied load, is the thickness of the specimen, is the crack length, and is the effective width of the specimen being the distance between the centreline of the holes and the backface of the coupon.
A pull-off test, also called stud pull test, is a type of test in which an adhesive connection is made between a stud and a carrier (or object to be tested) by using a glue, possibly an epoxy or polyester resin, that is stronger than the bond that needs to be tested.
In addition to coating the substrates with an adhesion promoter to enable good adhesion, surfaces can also be modified by various methods to prepare them for gluing. The most common surface pre-treatment methods are listed in the adjacent figure. The most important processes for surface pre-treatment (after H. Gleich) [4]
The mixed type, which occurs if the crack propagates at some spots in a cohesive and in others in an interfacial manner. Mixed fracture surfaces can be characterised by a certain percentage of adhesive and cohesive areas. The alternating crack path type which occurs if the cracks jump from one interface to the other. This type of fracture ...