Additive Phase Structure on the Mechanical-thermal and Tribology Properties of Cu/PTFE Composites

In order to investigate the effect of additive phase structure on the mechanical-thermal and tribology properties of Cu/PTFE composites. In this paper, the PTFE, particle-reinforced Cu/PTFE composites and three-dimensional skeleton-reinforced Cu/PTFE composites were respectively prepared by the vacuum hot-pressing and sintering method. And, the microstructure, mechanical properties, thermal conductivity and tribology properties of these three materials were investigated by using the Scanning electron microscope (SEM), X-ray diffraction (XRD), DR-III thermal conductivity tester, and UMT friction wear tester. The results showed that the copper particles in the particle reinforced Cu/PTFE composites were uniformly distributed in the PTFE matrix, and the skeleton Cu in the three-dimensional skeleton reinforced Cu/PTFE composites was tightly bonded with the PTFE matrix through interlocking mode. The three-dimensional skeleton reinforced Cu/PTFE composites compared to particle-reinforced Cu/PTFE composites, the three-dimensional skeleton reinforced Cu/PTFE composites were better crystallized in the composites during composites preparation due to the homogeneous thermal conductivity of the skeleton Cu, then its matrix hardness was slightly improved. The load-bearing and thermal conductivity of PTFE matrix composites were effectively enhanced by the addition of copper metal phase. For particle reinforced Cu/PTFE composites, the copper particles dispersed in the PTFE matrix and formed a structural discontinuity, so it improved the thermal performance at certain limitations, But, the three-dimensional skeleton reinforced Cu/PTFE composites could form a continuous thermal conductivity channel and can effectively dispersing the load , resulting in the thermal conductivity and load-bearing capacity of three-dimensional skeleton reinforced Cu/PTFE composites is significantly good than that of the particle reinforced Cu/PTFE composites. Friction and wear results showed the friction coefficient of three-dimensional skeleton reinforced Cu/PTFE composites was slightly higher than that of PTFE and particle reinforced Cu/PTFE composites. And, the particle-reinforced Cu/PTFE composites showed a small upward trend of the friction coefficient, which may have been attributed to the hard copper particles in the composite was gradual exposure out and resulting in the fluctuations of the friction coefficient. By comparing with the PTFE materials, the addition of copper metal phase significantly improved the wear resistance of PTFE-based composites. The plastic deformation in the matrix of the particle-enhanced Cu/PTFE composites and the three-dimensional skeleton reinforced Cu/PTFE composites was gradually reduced. In addition, the void structure of the copper foam skeleton has the accumulation of wear debris which could promoted the formation of the transfer film. So, the wear resistance of particle-reinforced Cu/PTFE composites and three-dimensional skeleton-reinforced Cu/PTFE composites were improved by 32.9% and 75.7%, respectively.