Scratch test apparatus

Although HIP treatment at 0.15 GPa induced almost no sintering, higher pressure and temperature conditions on the octahedral anvil apparatus improved compaction. Sintered samples (columnar, 3.4 mm OD X 5.0 mm long) prepared at 3 GPa and 823 K have good mechanical strength and hardness as determined by a conventional scratch test. 

Scratch Test. Many methods have been developed for testing scratch resistance. The method standardized in ISO 1518 employs a scratching needle with a hardened steel hemispherical tip of 1 mm diameter. The needle is moved along the surface of the coating under a specified load either in a hand-operated or in a motor-driven apparatus. 

Testing. In order to measure the wear flat diameter of the truncated cone, steel pins are fixed in test apparatus scratching against a... 

If you had a good means for measuring thermal conductivity, would you prefer such a test to Mohs scratch test How sensitive would your apparatus need to be We can use a hand-held tester to distinguish diamond and moissanite. How is this fact connected to the electronics industry ... 

In order to improve the scratch test, more sophisticated apparatus have been developed The normal load is not only controlled to determine the critical load Wc to initiate delamination, but also the optical microscopy for the monitoring the scratch and the acoustic spectroscopy for detecting the acoustic emission are equipped. 

A popular scratch test for plastics used in automotive applications is the Five Finger Scratch and Mar Tester. This apparatus includes a movable sledge and five fingers that include scratch pins, either 1.0 mm or 7.0 mm spherical balls. Each pin is loaded with different weights, such that they exert a standard force on the test surface ranging fi om 0.6N to 25N. The speed of the test is 100 mm/second. 

A common apparatus used in the paint industry to measure scratch resistance on smooth surfaces and coatings is the Wolff-Wilbom PencU Hardness Test. Using constant pressure and pencils of varying hardness (usually 6B to 6H), the pencil is held at a fixed angle of 45° to the specimen surface and pushed about 6.5 mm away from the operator under a fixed pressure of 7.5N. This test is repeated using softer lead until one is found that will not cut through the coating or indent the surface. 

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