掺杂锆再结晶石墨微观结构及其性能的影响  

Research on microstructure and physical properties of recrystallized graphiteby zirconium

作　　者：邱海鹏 宋永忠 等 

机构地区：中国科学院山西煤炭化学研究所，山西太原030001

出　　处：《航空材料学报》2003年第1期29-33,共5页Journal of Aeronautical Materials

基　　金：自然科学重点基金(197895037)

摘　　要：用煅烧石油焦作填料，煤沥青作粘结剂，锆粉作添加剂，采用热压工艺制备了一系列不同质量配比的掺杂锆再结晶石墨。考察了不同质量配比的添加锆对再结晶石墨的热导率，电阻率和抗折强度的影响以及微观结构的变化，实验结果表明，与相同工艺条件下制备的纯石墨材料相比较，掺杂锆再结晶石墨的导热，导电以及力学性能均有较大的提高，当锆掺杂量为6wt%时，再结晶石墨电阻率有明显的降低，而当锆掺杂量超过6wt% 时，对再结晶石墨的电阻率影响不大，室温下，RG-Zr-12再结晶石墨的层面方向热导率可达410W/(m·K）。微观结构分析表明，随着锆掺杂量的增加，石墨结晶的石墨化度以及微晶尺寸增大，晶面层间距降低。原料中掺杂锆量为12wt%时，再结晶石墨的石墨化度为97.7%微晶参数La为475nm，XRD及SEM分析表明，锆元素在再结晶石墨中以碳化锆的形式存在，锆对再结晶石墨制备过程的催化作用可以用液相转化机理来解释。The recrystallized graphite was prepared from filler of calcined coke & binder of coaltar pitch and zirconium by the hotpressing progress in order to investigate the effects of amount of zirconium on the thermal conductivity, electrical conductivity, bending strength and microstructure of recrystallized graphite Experimental results showed that the recrystallized graphite with a amount of zirconium exhibited higher thermal conductivity, higher electrical conductivity and bending strength than the pure graphite by the same process The dopant concentration of zirconium with 6wt% might greatly decrease the electrical resistivity of recrystallized graphite, but more dopant zirconium changed electrical resistivity of recrystallized graphite a little For the high conductivity direction, the thermal conductivity of RGZr12 was 410W/(m·k) Microstructural analyses revealed that the degree of graphitization of recrystallized graphite and coherence length of La increased and layers spacing of microcrystalline decreased with increasing zirconium concentration The degree of graphitization of recrystallized graphite was 977% and coherence length of La was 475nm when the amount of dopant zirconium was 12wt% Composition analyses indicated that zirconium added to the carbon substrate was in the form of ZrC precipitates by XRD and SEM The mechanism of the solutionprecipitation using liquid solvent could be explained the catalytic mechanism of zirconium dopant servers as catalyst to accelerate the graphitization of carbon substrates

关 键 词：掺杂锆 再结晶石墨 微观结构 热导率 电阻率 

分 类 号：TQ127.1[化学工程—无机化工]