| Ceramic-polymer composites,widely used in various fields such as tribology,are typically composed of ceramics as the matrix with the addition of polymers.This allows for the effective combination of wear resistance from ceramics with self-lubrication properties of polymers,retaining high-temperature stability while improving the toughness and friction performance of ceramic materials.The significant sintering temperature difference has been a major limitation for the composite of ceramics and polymers.Cold sintering technology has overcome this barrier,which is of great significance for the development of ceramic-polymer composites.In this study,h-BN@SiO2 core-shell composite particles were obtained through modified coating method,with h-BN as the"core"and SiO2 as the"shell".It was found that SiO2 chemically bonded to h-BN through Si-O-Sibonds,and the shell layer of SiO2 existed in an amorphous form.The amount of SiO2 coating increased with the increase of TEOS dosage and ammonia concentration,resulting in a more continuous and dense coating layer.However,excessive TEOS dosage and ammonia concentration led to the formation of free SiO2.The optimal coating effect was achieved with a TEOS dosage of 1.6m L and an ammonia concentration of 0.2mol/L.The effects of process parameters on the Vickers hardness,crystalline phases,and frictional wear performance of h-BN@SiO2/PEEK composites were investigated.It was found that the Vickers hardness of h-BN@SiO2/PEEK composites increased threefold compared to h-BN/PEEK composites without coating when the TEOS dosage was 0.8ml.The maximum hardness value of 154.78HV was obtained at a molding pressure of 550MPa.The effects of SiO2 coating content,PEEK addition amount,sintering temperature,molding pressure,and transient liquid phase content on the frictional wear performance were studied.The wear mechanisms were identified as abrasive wear,adhesive wear,and fatigue wear.The h-BN@SiO2/PEEK composite exhibited the best frictional performance with a coefficient of friction of 0.37 and a wear rate of 1.40×10-4mm3（Nm）-1 when the PEEK content was 35vol%,the sintering temperature was 285℃,the molding pressure was450MPa,and the transient liquid phase content was 25wt%.The effect of operating conditions on the friction and wear performance of h-BN@SiO2/PEEK composite materials was investigated.The friction coefficient of the h-BN@SiO2/PEEK composite material initially decreased and then increased with increasing applied load and sliding speed.The wear mechanism was primarily abrasive wear and adhesive wear,with abrasive wear becoming more prominent with increasing load,while adhesive wear was more pronounced with increasing sliding speed.The optimal friction and wear performance of the h-BN@SiO2/PEEK composite material was achieved at an applied load of 40N and a sliding speed of 3.2cm/s. |
PDF Full Text Request