Preparation of polyimide-graphite composite and evaluation of its friction behavior at elevated temperatures

In this paper, polyimide-graphite (PG) composite was prepared and used as a solid lubricant at elevated temperatures. PG composite was characterized by X-ray diffraction, and its thermal stability was evaluated based on thermogravimetric/differential thermal analysis and Fourier transform infrared spectrometry analysis. The results show that in PG composite, there was some interaction between the graphite (GR) and the polyimide (PI) matrix. Consequently, the PG composite exhibited better thermal stability than PI. The friction behavior of the PG composite sliding against steel at elevated temperatures (300-600 degrees C at an interval of 100 degrees C) was evaluated with a ring-on-ring tribometer. It was found that the PG composite exhibited excellent friction-reducing ability and good load-carrying capacity in the temperature range of 300-600 degrees C and applied loads of 300-700 N. Moreover, this excellent lubricating performance of the PG composite might be attributed to its good thermal stability as a result of the interaction between the GR and the PI matrix. Therefore, PG composite could be used as an excellent solid lubricant under the high-temperature conditions.