Preparation And Properties Of The Three-dimensional Network Alumina Composite Ceramic/High Chromium Cast Iron Composite

Three-dimensional network alumina composite ceramic / Fe composite materials have broad application in the military plates,mechanical processing,auto industry,aerospace and food processing and other fields because of its good abrasion resistance,high temperature resistance,high temperature oxidation resistance,creep resistance and structural characteristics in the three-dimensional space through the phase.However,alumina ceramics and iron alloy belongs to none wetting system,so that the combination of the two is very poor,poor combination result to poor properties of composite.In this experiment,copper coating was prepared on the surface of alumina composite foam ceramics by chemical vapor deposition technique to improve the wettability between the alumina composite ceramics and high chromium cast iron,and to determine the suitable process parameters.Vacuum EPC was used to prepare the alumina composite ceramic / high chromium cast iron composite materials with three-dimensional network,and the interfacial combination of composites was analyzed.Finally,the mechanical properties and wear resistance of the composites were studied.The results show that:(1)A dense,uniform and high purity copper coating can be deposited on the surface of alumina composite foam ceramics by chemical vapor deposition,the copper coating can cover the framework and the interior pores of the foam ceramics uniformly.According to the experiments,the suitable process parameters to prepare the copper coatings by chemical vapor deposition are as follows: the hydrogen flow rate is 150 mL/min,the argon flow rate is 300 mL/min,the temperature of deposition is 850 ℃,holding time is 40 min;(2)The alumina composite ceramic / high chromium cast iron three-dimensional network composite materials can be prepared by the vacuum EPC successfully,there are no defects such as cracks and holes in the alumina composite ceramics and high chromium cast iron.In the composites,the alumina composite ceramics and high chromium cast iron are embedded in each other with the rough interface,forming a mechanical combination.At the same time,the dissolution and diffusion of the elements near the interface of composites were carried out at high temperature,which is benefit to the combination of interface.The composite materials form a hybrid interface with mechanical bonding and dissolution diffusion at the interface;(3)The bending strength of the composites is 2.1 times that of the composite ceramics.The friction and wear properties of the composites and high chromium cast iron were tested at room temperature,the friction coefficient of the composites was less than that of high chromium cast iron,so that the wear resistance of composites are superior to that of pure high chromium cast iron.Based on the analysis of wear surface micro topography,the main wear modes of pure high chromium cast iron is oxidation wear.In the composites,the hard ceramic framework can bear the main friction load,slow down the wear of the metal matrix and improve the wear resistance of the composites;(4)Abrasive wear of pure high chromium cast iron and composites was tested.The results show that under the same load,the wear of pure high chromium cast iron is obviously higher than that of the composites,and with the increase of the load,the wear of the composites increases gradually.In the process of abrasive wear,the abrasive wear of composites is mainly micro cutting and fracture of metal matrix,the ceramic reinforcement of the composites can bear a large friction load,effectively reduce the wear of the metal matrix and improve the abrasive wear resistance of the composites.