Experimental Investigation on Friction and Wear Performance of C/C Composite Finger Seal

Abstract In order to find a good friction pair for the finger seal, the pin-on-disc friction tests matching the actual working conditions of finger seal are designed based on the performance simulation of finger seal and the similarity principle of PV value, in which the friction characteristics between pins with two different materials (C/C composite or cobalt-base alloy GH605) and discs with two different coatings (Cr3C2 or Al2O3) are tested and analyzed respectively; the test results show that the wear loss of all the friction pairs increases with the load increasing, but the friction coefficient of the C/C composite pin (no matter contacting with Cr3C2 or Al2O3 coating) is much less than that of GH605 pin; in the four kinds of friction pairs, the C/C–Cr3C2 pair has the greatest friction characteristics and least wear loss. Then, to verify the application feasibility of C/C composite in the finger seal further, the bench-scale performance test of the finger seal with C/C–Cr3C2 pair (the finger seal is made of C/C composite, and the rotor surface is coated with Cr3C2) is carried out with a self-developed testing rig; according to the leakage and wear results before and after the durability test lasted for 60 h, there is little distinct trace of destruction on the friction surfaces of finger seal with C/C–Cr3C2 pair after the durability test, which is in good agreement with the result of pin-on-disc friction test; besides, after the durability test, the static leakage of finger seal with C/C–Cr3C2 pair becomes lower than that before and is lower than that of finger seal made of GH605. The test results in this paper indicates that the C/C–Cr3C2 pair has nice friction characteristics and can be a good choice for the friction pair of the finger seal.