The test was conducted under atmospheric conditions and dry friction conditions. The test temperature was room temperature, the load was 20N, the sliding speed was 4.6m/s, and the total sliding stroke was 1920m. Before and after the test, put the sample into a beaker containing acetone solution, clean it in an ultrasonic cleaner for 3~5min, and then use a Sartorius BS224S electronic balance with an accuracy of 0.1mg to weigh the mass loss of the sensing pin sample before and after wear; Use AF-LI contact and non-contact surface profiler with accuracy of 2 to measure the width and depth of the pit on the worn surface of the disc sample, and calculate the wear volume loss of the pin and disc. The average friction coefficient at the stable stage is selected as the test result, and the arithmetic mean value of the three test results is taken for all wear quantities. According to ASTM-C633-2001 Standard for Bonding Strength Test of Thermal Sprayed Coatings, WE-50 hydraulic tensile tester is used to measure the bonding strength between the coating and the substrate. The thermal shock test of coating is to put the sample into a box type electric furnace at 800 ℃, keep it for 20 minutes, then take it out, put it into cold water at room temperature and quickly cool it to room temperature. Repeat the cycle for 100 times or until the coating falls off. Observe the change of the coating after each thermal cycle, and record the number of thermal cycles for the first crack and the first falling off.

Application of non-metallic contraction joints
The good comprehensive properties of non-metallic contraction joints make them widely used in many engineering fields.
In the pipeline system, if the thermal stress caused by temperature change, the partial stress caused by equipment vibration and fixed support, and the stress caused by system device deflection exist at the same time, the rigid connection mode will inevitably lead to deformation or destruction of the pipeline system at the thinnest place. If flexible non-metallic compensators are used, this kind of destruction can be prevented. This is related to the unique motion mode of non-metallic compensator. These motion modes determine the multi-dimensional displacement performance of non-metallic compensators.
Pressure bearing single wave body and multi wave body compensators play an irreplaceable role in some special working conditions. The electronic weighing scale used in the desulfurization and powder injection system of a steel plant was originally used to compensate equipment and pipelines with metal compensators. Due to the large reverse thrust, the electronic weighing scale was not accurately debugged and could not return to zero and weigh correctly. The ventilation, dust removal, smoke exhaust and air conditioning insulation pipes and equipment with low working pressure usually use the Pingcheng compensator.