Preparation And Properties Of Aluminum Dross Reticulated Ceramic/Phenolic Modified Epoxyresin Composites

Aluminum dross,as a large amount of solid waste generated during the aluminum smelting process,undergoes desalination,denitrification,and fluorine fixation treatment to obtain secondary aluminum dross（SAD）,providing a rich aluminum source for the production of porous ceramics.Composite made from ceramic bodies and resins are used as friction materials allows for lightweight and cost-effective brake pads.In this thesis,the SAD reticulated ceramic was prepared by the gel casting/sacrificial template（GC/ST）method and using SAD as the raw material and kaolin as the sintering agent.The phenolic resin was selected to modify the epoxy resin to obtain the phenolic modified epoxy resin（PMEP）as the matrix and SAD reticulated ceramic to prepare SAD reticulated ceramic/PMEP composite.This thesis firstly investigated the physical composition and microstructure of SAD,as well as the optimum sintering temperature,kaolin addition and sintering process for the preparation of SAD ceramic,the microstructure,physical composition,mechanical properties and internal morphology of SAD ceramic.Secondly,the optimum temperature and time for the semi-gel of the homemade phenolic resin,the curing mechanism of PMEP,the physical and mechanical properties of PMEP with different phenolic resin contents and the heat resistance of the optimum phenolic resin content,and the wetting properties of the three resin liquids with ceramics were investigated.Finally,the interfacial bonding states of the three resins to the ceramic composites and the friction properties of the SAD reticulated ceramic/15 wt.%PMEP composites were investigated,including friction coefficients,wear mechanisms,wear rates,energy dissipation and hardness before and after friction.The following conclusions were drawn from the study:（1）The SAD is mainly composed of Mg Al₂O₄ and Al₂O₃,and the optimum sintering temperature for SAD ceramics is 1450℃.With the addition of kaolin,solid and liquid phase sintering occurs during the sintering process and the ceramic physical phase composition is mainly Mg Al₂O₄,Al₂O₃ and Na Al₁₁O₁₇.The optimum sintering process is 1450℃ and the addition of 30 wt.%kaolin resulted in a ceramic with the shrinkage of 18%,the porosity of 32.87%and the compressive strength of 31.9 MPa.Without the addition of kaolin,the ceramic had large internal fissures,which were significantly resolved by the addition of kaolin.（2）The phenolic resin was prepared by heating phenol and formaldehyde in the alkaline environment with the optimum semi-gel temperature of 90℃ for 110 min and the solids content of 81.36%after treatment.The phenolic resin will increase the cross-linking of the PMEP and the addition of the phenolic resin,curing agents and accelerators will cause a series of reactions with the epoxy resin and the curing mechanism is complex.As the phenolic resin increases,the cured density and hardness rise and the impact strength decreases.15 wt.%PMEP has the best overall performance,when the density and hardness are 1.195 g/cm³ and 32.1 kg/mm² respectively,and the impact strength is 5.36 k J/m².The heat resistance is higher than that of the epoxy resin and slightly lower than that of the phenolic resin.The wettability between 15 wt.%PMEP and the SAD ceramic is lower than that of phenolic resins and better than that of epoxy resins,and the overall state is wettable.（3）The 15 wt.%PMEP is not as good as the interfacial bonding state between epoxy and phenolic resins and SAD ceramics,but still penetrates sufficiently into the ceramic pores.The SAD reticulated ceramic/15 wt.%PMEP composite is carbonized during the friction process and the wear mechanisms are abrasive and adhesive wear.The friction coefficient,wear rate and energy dissipation increase with increasing load.The coefficient of friction and energy dissipation are lowest with 30 wt.%kaolin and highest with 20 wt.%kaolin,and the hardness after friction is higher than the hardness before friction.