GB/T 40398.1-2021Test method for C-C composites—Part 1: Friction and wear property (English PDF)

3.1 C-C composites

Carbon fiber-reinforced carbon matrix composites.

3.2 The ratio of energy to area

The energy carried by the friction pair per unit area.

3.3 The ratio of energy to mass

The energy carried by the friction pair per unit mass.

3.6 Linear wear

The ratio OF the average thickness difference of the friction pair before and after the test TO the number of tests.

3.7 Mass wear

The ratio OF the mass difference of the friction pair before and after the test TO the number of tests.

3.8 Interface pressure

The ratio of the vertical pressure on the contact surface to the macroscopic contact area.

5.1 Testing machine

The testing machine adopts the frictional thermal shock test method, and conducts the dynamic simulation test of the laboratory small sample scale of C-C composites under the simulated actual working conditions, which can meet the functions of automatic collection, processing and result output of parameters such as braking pressure, speed, time, braking torque, friction coefficient, braking power and absorbed energy. Among them, the speed control error, pressure control error and torque control error of the testing machine are ±1% of the full scale; the inertia error of the test configuration shall not be greater than 0.01 kg·m2.

5.2 Measurement equipment

5.2.1 Micrometer

6.2 Sample preparation

The sample preparation shall follow the following principles.

a) After the sample piece is cut from the product, the rotating ring, stationary ring and corresponding friction surface shall be marked in time;

b) The processed samples shall be visually inspected for appearance, and there shall be no defects such as fiber peeling, holes, falling edges and corners.

6.3 Number of samples

The valid sample for friction and wear is 1 pair.

8.1 Preparation before the test

8.1.1 Visually inspect the friction pair to ensure that there is no blockage, peeling, etc., and number the rotating and stationary rings of the friction pair.

8.1.2 Check the air pressure system of the testing machine and debug the torque zero point.

8.2 Running-in test

8.2.1 Assemble the friction pair on the testing machine.

8.2.2 Start the testing machine and carry out the running-in test according to the test parameters in Table 2. After the running-in test, the friction surface of the friction pair shall be at least 80% in contact with each other. […]