Preparation and Pore Forming Mechanism of Polyphenylene Sulfide/Melamine‐Formaldehyde Resin Porous Oil‐Bearing Cage Materials With Low Friction

ABSTRACT Porous oil‐bearing cages are widely used in the aerospace industry. However, traditional porous oil‐retaining cage materials suffer from insufficient friction and wear performance, as well as unclear lubrication mechanisms and so forth. This study employed polyphenylene sulfide (PPS) as the matrix material and selected melamine formaldehyde resin (MF) as the pore‐forming agent and binder. The formation mechanism of pores in PPS/MF and the oil storage and wear properties of composite materials were discussed through microscopic observation. Results indicated that MF releases gas to generate initial pores during the curing process, while MF shrinks and forms a porous skeleton. Subsequently, PPS was fused and connected to form a porous structure under the support of the MF framework in the sintering stage. Moreover, the centrifugal test indicated that under the conditions of 20°C, 6000 rpm, a centrifugal radius of 0.1 m, and a duration of 2 h, the oil retention rate reached 98.78%. The friction and wear tests demonstrated that oil immersion significantly reduced the friction coefficient and specific wear rate of the porous material to 0.071 and 5.24 × 10 −5 mm 3 /(N·m), respectively. The PPS/MF porous material prepared in this study provides a new solution to the problem of lubrication failure under extreme conditions.