Fabrication And Property Regulation Of Bionic Composites Based On Shell Structure

Bearing is an important component in drilling system.It is easy to be damaged during drilling.Therefore,the performance and service life of bearing materials greatly affect drilling efficiency and engineering cost.Ceramic materials have high hardness,wear resistance and self-lubrication in the friction process.These superior properties enable them to be applied in many fields.However,ceramic materials also have some defects that can not be ignored,such as poor toughness.This property defect seriously limits the application of ceramic materials.The microstructures of shells not only ensure good strength,but also obtain good toughness.By transplanting this structure into ceramics,a shell-like ceramic composite material is prepared,which improves the toughness of the ceramic material and can be used as bearing material for oil and gas wells under special working conditions.In addition,in addition to the ceramic structure,the choice of reinforcing phase composition also has an important impact on the properties of composites.Therefore,three kinds of nanoparticles were used to improve the tribological properties of PMMA,namely Zr O₂?Ti O₂ and Si O₂.Sixteen samples including blank control group were prepared.After surface treatment,friction and wear tests were carried out.It was found that the effect of three materials on PMMA was different under different working conditions.Under the condition of water-based drilling fluid,adding1%Zr O₂ composite material has the most obvious antiwear effect.Under dry friction condition,the friction coefficient of the material decreased obviously after adding 1%titanium dioxide,1%Zr O₂,1%Si O₂,3%Si O₂ and 7%Si O₂.Under the condition of water-based lubrication,the composites with 1%Zr O₂,3%Zr O₂,1%Si O₂,3%Si O₂,5%Si O₂ and 7%Si O₂ all have good antiwear effect.The porous ceramic skeleton with five water contents was prepared by directional solidification,freeze-drying and high-temperature sintering.Because the water-based drilling fluid in the normal working environment of drilling bearings and the PMMA material with 1%Zr O₂ were well behaved under various working conditions,PMMA with 1%Zr O₂ was used as the reinforcement phase material of layered ceramics.By means of bulk polymerization,the reinforced phase material was filled into the pore space of porous ceramic skeleton through the processes of pre-polymerization,casting,polymerization and demoulding,and the laminated ceramic composite Al₂O₃/PMMA/Zr O₂ was prepared.Friction and wear tests were carried out on the materials after surface treatment,and their microstructures were observed by scanning electron microscopy?SEM?.It is found that under the condition of water-based drilling fluids,the friction coefficient of materials increases with the increase of loading load.First,the friction coefficient decreases to the lowest value and then increases.Under the condition of dry friction,the friction coefficient of materials increases with the increase of loading load.Under the condition of dry friction,the friction coefficient of materials decreases with the increase of loading load.In this paper,the erosion test of the composites is carried out.It is found that the erosion wear degree of the composites tends to be serious with the decrease of PMMA content when the erosion angle is 90 degrees;the erosion wear degree of the composites increases with the increase of PMMA content when the erosion angle is 45 degrees;and the erosion wear degree of the composites increases with the increase of PMMA content when the erosion angle is 60 degrees.The decrease first decreases and then increases.When the PMMA content is 80%,the erosion wear is the smallest.