【作者】 贾晓伟；

【导师】 周洋；

【作者基本信息】 北京交通大学 ， 材料加工， 2008， 硕士

【摘要】 Ti₃SiC₂系三元层状陶瓷是近年来受到广泛重视的一种新型化合物材料,它同时具有金属的导电、导热等性能和陶瓷的低密度、高熔点、高稳定性等性能。与目前触头材料中常用的增强相碳化钨相比,其电阻率相当,热导率和熔点更高,模量和热膨胀系数更接近于金属,比重更轻,同时具有良好的自润滑性和抗氧化性。用它代替碳化钨和铜进行复合,将能够减轻触头重量、降低材料成本的同时,提高材料的电接触性能,同时节省宝贵的战略资源钨,因而有望成为一种新型的高性能触头材料。本试验在高纯度Ti₃SiC₂粉体合成的基础上,用热压法制备出Ti₃SiC₂与Cu的复合材料。测试密度、导电性、抗弯强度等物理、力学性能,并对材料进行XRD分析、SEM微观分析、EDS微观区域分析。根据试验结果,对Ti₃SiC₂与Cu的体积比、烧结温度、保温时间、压力大小等组分与工艺进行了优化,以求得到高导电性、高强度的Ti₃SiC₂-Cu复合材料。试验结果表明,影响材料性能的因素主要有两个,即致密度和界面反应程度。提高致密度有助于提高材料的导电性和抗弯强度,而界面反应则会在提高材料强度的同时降低导电性。在相同的工艺条件下,铜的增加会提高材料的致密度及导电性,当铜体积含量达到60%时,材料表现一定的塑性;Ti₃SiC₂含量增加,材料脆性增强;增加保温时间和增大烧结压力,也会提高材料的致密度。本实验范围内,当复合材料为50vol%Ti₃SiC₂-Cu,烧结温度1000℃,保温时间30min,强度达到最高值,为1351.78MPa;当复合材料为40vol%Ti₃SiC₂-Cu,烧结温度1000℃,保温时间60min,电阻率达到最低值,为0.06μΩ^*m。更多还原

【Abstract】 The ternary compound Ti₃SiC₂ has been layed more emphasis as a new compound material,and its electric and thermal conductibility is similar to metal,and its low density,high melting point and high stabilization are similar to ceramics. Compared with WC which is usually used as electrical antenna material,Ti₃SiC₂ has similar resistance,better thermal conductibility and higher melting point.Its elasticity modulus and thermal dilatability are more adjacent to metal,and it has lower specific gravity,its self-lubrication and resistance to oxidation is better.Componded with copper instead of WC,it can diminish density,lower cost,improve the capability of electric contact and save W which is a kind of valuable resource.Because of these reasons,it is hopeful to be used as a new electric contact antenna with high performance.On the basis of the synthesis of high purey Ti₃SiC₂ powder,we prepared Ti₃SiC₂-Cu composites through hot-press process.We test its density,electric conductivity,flexural strength and so on,and we study the composites through XRD, SEM,EDS.With the referrences to experimental result,we adjust the volume proportion of Ti₃SiC₂ and Cu,temperature,dwelling time,pressure to get the Ti₃SiC₂-Cu composites with high electric conductivity and flexural strength.The results show that there are two main factors that influence the result,which are compact degree and interphase reaction.The compact degree is favorable to the electric conductivity and flexural strength,the interphase reaction is favorable to flexural strength but it is bad to electric conductivity.With the same process,we can increase Cu’s volume content to improve the material’s compact degree and electric conductivity,when the volume content of Cu is no less than 0.6,the composites have plastisity;Improve the volume content of Ti₃SiC₂,the material’s brittleness will be improved;increasing dwelling time or pressure,the composites’ compact degree will be improved.The composites with highest flexural strength we prepared is 50vol%Ti₃SiC₂-Cu,the sintering temperature is 950℃,keeping-temperature time is 30min,and the flexural strength value is 1350Mpa;The composite with highest electric conductivity we prepared is 40vol%Ti₃SiC₂-Cu,the sintering temperature is 1000℃, keeping-temperature time is 60min,and the electric resistivity value is 0.06μΩ^*m。更多还原