In this work, metal ion implantation was employed to improve the mechanical properties of Al 2 O 3 /polytetrafluoroethylene (Al 2 O 3 /PTFE). Four metal ions (Al, Cr, Ni, and Ag) were selected as the implantation source, respectively, and the implantation process was optimized by SRIM method. Optimization results revealed that, among these four metal ions, implantation of Al ions exhibited the best modification for Al 2 O 3 /PTFE composite layer, when the particle distribution section,

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... ion range and energy exchange were concerned. Al ion implantation could minimize the damage of carbon skeleton and lamellar structure of Al 2 O 3 /PTFE substrate, which kept strong scattering of Al ions and obtained the thick and uniform coating on the surface of Al 2 O 3 /PTFE substrate. The uniformity of Al 2 O 3 /PTFE layer was improved with the increase in Al ions implantation dosage and the best dosage of Al ions was regarded as 1×10 16 ions/cm 3 with the implantation energy of 20KeV. After implantation modification, the mechanical properties of Al 2 O 3 /PTFE layer were obviously improved. The hardness (H)of samples was detected to be 0.65GPa and elastic modulus (E) 2.2 GPa, with a higher H/E value of 0.295, which was 10 times higher than original PTFE. program of simulating radiation damage of ion in the material and calculating resistance and range distribution of ion (10eV ~ 2GeV) in solid [16] . Fixed-point implantation method was used in optimization experiment. Ions implantation rate were 290-295 ions/min. Ion distribution curve could be obtained after Al ion implantation of 230 minutes approximately. Special notes: too large computation of simulation software would cause fault of system because of memory. In order to control the time of the experiment, simulation experiment of implantation dose of 1×10 16 ions/cm 3 was conducted on the material surface of 40nm thickness. From the analysis of the experimental results, collected simulation characteristic value was enough to continue experiment. The incident angle was calculated by MACIC algorithm. Atomic binding energy E, atomic binding energy in the body E b, atomic displacement energy E d and atomic density ρ of substrate surface were set by SRIM, which was obtained from first principle calculations[17]: density of PTFE was 2.2g/cm 3 , E disp is equal to 28ev and E surf is equal to 2ev and E latt is equal to 7.47ev for carbon atom . E disp is equal to 25ev and E surf is equal to 2ev and E latt is equal to 3ev for fluorine atom . PTFE Modified Experiment Al 2 O 3 / PTFE nano-composite layer was fabricated in matal vacuum room of MEVVA by Bunch Plasma Beam Implantation Technology. the maximum acceleration voltage of ion implanter was 40KV. Aluminum ion energy was 20KeV. Three kinds of does for ion beam were 1X10 15 ion/cm 3 、5X10 15 ion/cm 3 and 1X10 16 ion/cm 3 , Current Density was 10uA/cm 2 .Al 3+ was implanted under pressure was 2X10 -4 Pa, running pressure was 3X10 -3 Pa.