Sliding-block friction test

Sliding-Block Friction Test. In the sliding-block friction test (Fig 1), a sample is subject to frictional forces when clamped between two prepared steel surfaces (Ref 2). The upper sliding block is constrained to move horizontally over the lower fixed block by guides. A pedal-operated mechanism permits the load to be released so that the sliding block assembly can be inserted... 

Among many shear-type tests the following are representative the mallet friction test, the sliding-block friction test, and the emery-paper friction test of the Explosives Research and Development Establishment, England, the U.S. Bureau of Mines pendulum friction test, and the Julius Peters friction test. Each of these can be used to test primary explosives, and some may be used also on secondary explosives. 

A sliding-block friction test apparatus is located at Picatinny Arsenal. 

With the Julius Peters apparatus lead azide and mercury fulminate ranked in the same order (Table XV) as those obtained with grit or the sliding-block friction test. 

While the blocking load test measures the force to separate the films perpendicular to their plane, a different method is used to measure the frictional forces required to slide one layer of film over another (ASTM D1894). In this test, a small sled drags one layer of film over another. A load cell measures the force required to initiate a sliding motion (related to the static coefficient of friction) and maintain a sliding motion (related to the kinetic coefficient of friction). 

The friction coefficient and the specific wear rate of the nanocomposites were determined by sliding wear tests on a block-on-ring apparatus against a 100 Cr 6 (German standard) steel ring as the counterpart. A pressure of 1 MPa and a velocity of 1 m/s were used over a duration of 20 h for each sample. Additional wear tests of the composite systems were carried out under fretting test conditions against a ceramic ball as the counterpart. 

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