The Research On Tribological Properties Of Sealing Materials For Stirling Engine

The Stirling engine is a kind of external heating regenerative cycle engine with high pressure hydrogen or helium. The dynamic performance and reliability of the engine is closely related to its dynamic sealing technology. The energy consumption of the Sterling engine largely depends on the friction coefficient of the sealing material, and the anti-wear performance of the material is a key factor in its service life. Therefore, it is of great importance to invest sealing components with low wear rate and low friction coefficient.PPS-PTFE and two different nanoparticles reinforced PPS-PTFE composites were prepared by mechanical blending-molding-sintering methods. The tribological and wear behavior of the three composites sliding under different load, temperature, velocity were studied with a MRH-3block-on ring friction and wear tester. The results show that when the mass fraction of PPS was10%, the PPS-PTFE composites exhibit well mechanical and tribological properties, the anti-wear performance of10%PPS-PTFE is2times better than pure PTFE. With the addition of5%nano-Al2O3, the wear resistance of the composite is152times better than PPS-PTFE and276times than pure PTFE. The root cause of the improvement of wear resistance is the improvement of storage modulus, the uniform and smooth transfer film and tribochemical reaction also play a positive role during sliding process.But the nano-Al2O3filled composites are not suitable for working under heavy load. Nano-SiO2filled PPS-PTFE composites exhibits best anti-wear behavior, with the addition of5wt.%nano-SiO2filler, the wear resistance is improved161times compared with PPS-PTFE composite, and295times with pure PTFE.5%SiO2/10%PPS-PTFE shows the best tribological properties under heavy load, high temperature and high sliding speed, it is suitable for Stiring Engine as a sealing material.The results also show that the greatest impact on the anti-wear performance of composite for stirling engine is load, followed by the temperature, and the minimum effect is sliding velocity.