Scratch testing is invaluable to gain insight into materials such automotive paints, varnishes, as well as coatings. Scratch testing is a simple and rapid method of characterizing coatings, but results obtained are influenced by various factors such as coating thickness, substrate mechanical properties, interfacial bond strength, and test conditions such as scratch speed, load, and indenter tip radius.Single asperity scratching allows the mechanisms behind abrasive or ductile damage to be understood without the complexity of multiple asperity contacts.
Scratch Test：Using a scratch tester, qinsunlab is able to determine the critical load of a coating by detecting its initial failure. A Rockwell diamond tip with a radius of 200 µm is moved across the coated surface at a constant velocity while an increasing normal force is applied with a constant loading rate. This test introduces stresses to the interface between coating and substrate causing eventual delamination or chipping. qinsunlab identifies the precise force that causes initial failure to take place, giving you insight into your product or coating’s performance. This invaluable insight not only impacts quality, but also your bottom line.
Here, the work piece is held stationary and, commonly, a Rockwell diamond indenter with a tip radius of 200 μm is used to scratch the work piece for a predefined length with a predefined normal load. The load can be fixed or increasing progressively, depending on the requirement. The output is measured in terms of acoustic emission, penetration depth, and tangential frictional force. Transducers are used for measuring the frictional force acting at the tip of the indenter. The onset load for coating cracking is commonly referred to as the critical load and, as can be seen in Figure is associated with the rise in value of coefficient of friction and acoustic emission used to assess the coating-substrate adhesion.
The morphology of the scratch track and transverse cracks provide information on failure mechanisms such as cohesive, interfacial, conformal, and brittle chipping. The load at which the first crack appears is called a “lower critical load” and is a measure of the cohesion strength of the coating.
Scratch Test：Using a scratch tester, qinsunlab is able to determine the critical load of a coating by detecting its initial failure. A Rockwell diamond tip with a radius of 200 µm is moved across the coated surface at a constant velocity while an increasing normal force is applied with a constant loading rate. This test introduces stresses to the interface between coating and substrate causing eventual delamination or chipping. qinsunlab identifies the precise force that causes initial failure to take place, giving you insight into your product or coating’s performance. This invaluable insight not only impacts quality, but also your bottom line.
Here, the work piece is held stationary and, commonly, a Rockwell diamond indenter with a tip radius of 200 μm is used to scratch the work piece for a predefined length with a predefined normal load. The load can be fixed or increasing progressively, depending on the requirement. The output is measured in terms of acoustic emission, penetration depth, and tangential frictional force. Transducers are used for measuring the frictional force acting at the tip of the indenter. The onset load for coating cracking is commonly referred to as the critical load and, as can be seen in Figure is associated with the rise in value of coefficient of friction and acoustic emission used to assess the coating-substrate adhesion.
The morphology of the scratch track and transverse cracks provide information on failure mechanisms such as cohesive, interfacial, conformal, and brittle chipping. The load at which the first crack appears is called a “lower critical load” and is a measure of the cohesion strength of the coating.
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