喷雾干燥-氢还原制备超细/纳米晶W-10Cu粉末及其烧结行为  

Preparation and sintering behavior of ultrafine/nanocrystalline W-10Cu composite powders

作　　者：朱松[1] 范景莲[1] 刘涛[1] 田家敏[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2010年第4期373-377,共5页Materials Science and Engineering of Powder Metallurgy

基　　金：国家杰出青年科学基金资助项目(50925416);国家自然科学基金资助项目(50874122);国家自然科学基金委员会创新研究群体科学基金资助项目(50721003)

摘　　要：采用喷雾干燥-氢还原法制备超细/纳米晶W-10Cu(质量分数,%)复合粉末,并经过压制和烧结制备W-Cu复合材料,系统研究烧结温度和保温时间对该材料性能和组织的影响,以及在1 100～1 300℃温度范围内的烧结激活能。结果表明,W-10Cu还原粉末晶粒度仅为30～60 nm;在1 200℃烧结时开始发生明显的致密化行为;随烧结温度升高相对密度增大,当烧结温度升高到1 300℃时W-10Cu复合材料的相对密度为90%,但当温度达到1 460℃时有所降低。1 420℃保温90 min时材料相对密度高达99.1%,且此时晶粒度仅为1.8μm。W晶粒尺寸为30～60 nm的W-10Cu复合粉末在1 100～1 300℃烧结的平均激活能为129.14 kJ/mol。烧结温度为1 420℃时W-10Cu的电导率随保温时间延长先增大后减小,保温90 min时最大达到19 MS/m,超过国标有关规定。Ultrafine/Nanocrystalline W-10Cu（mass fraction,%） composite powders were synthesized by sol-spray drying and subsequent hydrogen reduction process.The W-Cu composite materials were fabricated through pressing and sintering.Effects of sintering temperature and holding time on material properties and microstructure were systematically studied.The sintering activation energy between 1 100 and 1 300 ℃ was also explored in the present paper.The results show that the grain size of W-10Cu powder is only 30～60nm and obvious densification takes place at 1 200 ℃.The relative density of about 90% can be obtained when the sintering temperature is 1 300 ℃.Then,the relative density increases with further increasing sintering temperature,while it will decrease when sintering temperature reach 1 460 ℃.When sintering at 1 420 ℃ for 90 min,the sintered compacts will reach the maximum relative density of 99.1%,and its grain size is only 1.8 μm at this time.The activation energy of the W-10Cu composite powders with W grain size of 30～60 nm is about 129.14 kJ/mol.With increasing holding time,the electric conductivity of W-10Cu increases at first and then decreases.In addition,W-10Cu reach the maximum conductivity of 19 MS/m when sintering at 1 420 ℃ for 90 min,and the value is 21.8% higher than National Standard of W-10Cu contact.

关 键 词：W-10Cu复合粉末 超细/纳米晶 烧结致密化 激活能 晶粒长大 

分 类 号：TG149.411[一般工业技术—材料科学与工程]