硬质合金上火焰法沉积复合结构的碳材料表征

【作者】 叶永权；

【导师】 白晓军； 匡同春；

【作者基本信息】 广东工业大学 ， 材料学， 2004， 硕士

【摘要】 本文重点对原始态、抛光态硬质合金表面火焰法沉积碳材料的复合结构进行表征，率先对火焰内焰中不同的高度位置所沉积的碳材料的形貌、相组成、晶粒尺寸等进行了系统探讨。主要开展了以下几方面的研究工作：（1）碳材料的扫描电镜表征与探讨；（2）碳材料的X射线衍射表征与探讨；（3）碳材料的Raman光谱表征与探讨。 选用原始脱钴YG8硬质合金作为基体，采用C₂H₂-O₂火焰法沉积复合结构的碳材料。火焰内焰不同高度位置所沉积的碳材料主要是由球状颗粒组成。随着喷嘴到基体表面距离的增加，形貌由“片层状组织”向“针杆状组织”变化，沉积碳材料的致密度和厚度相应降低。横截面观察结果表明，靠近外焰区域沉积碳材料时，观察到基体表层呈明显的超细化、纳米化现象。XRD和Raman光谱综合表征结果表明，沉积碳材料主要由纳米晶石墨和金刚石相复合而成。 抛光脱钴YG8硬质合金作为基体，采用C₂H₂-O₂火焰法沉积复合结构的碳材料。火焰内焰中不同高度位置所沉积的碳材料生长趋势与原始脱钴火焰法沉积产物相似，随喷嘴到基体表面距离的增加，高倍形貌由“片状组织”向纳米尺寸颗粒变化。XRD和Raman光谱综合表征结果表明，采用火焰法在抛光脱钴硬质合金基体上的沉积产物，主要是以纳米晶石墨、金刚石为主相，金刚石相以8H金刚石为主，同时还出现了6H、15R的金刚石。 同时，在两种预处理条件下硬质合金基体表面沉积的碳材料中，都能观察到以下规律： （1）随着喷嘴到基体表面距离的增加，L_a值变化趋势是先变大后变小。 （2）在514.5nm激光波长激发的拉曼光谱中，随着喷嘴到基体表面距离增加，沉积碳材料的二级拉曼峰呈现出从尖峰状向宽峰状转变趋势，与原始脱钴沉积样品有相似规律。 （3）比较514.5nm、785nm激光波长激发拉曼谱线，在石墨G峰位置观察到反常的色散现象，该现象值得进一步验证。更多还原

【Abstract】 In this paper, the composited carbon materials deposited on the cemented carbide surface by Combustion Flame method were studied. The influence of height between spray nozzle and cemented carbide and the morphology , phase composite, and grain size have been investigated, for the first time. The following investigations are mainly taken: (1) SEM inspection of deposited carbon material; (2) XRD inspection of deposited carbon material; (3) Raman spectrum inspection of deposited carbon material.The cemented carbides before and after polish were used as substrate respectively. After deposition, nanocrystalline graphite and polytyies of diamond were found on both substrates by both XRD and Raman. Increasing the height between spray nozzle and substrate, the value of La would increase firstly and then decrease.the second order Raman peak would also become widely and weakly. An abnormal dispersion of the Raman peak near G peak was found in this article.The shape of the particles deposited on the initial cemented carbide was spheral. Increasing the height between spray nozzle and substrate, the morphology of the particle surface will change from sheet to pin. it has been observed that the size of cemented carbide particles was finer after depositing using near - outer flame.On the other hand, the shape of carbon would change from sheet to sphere, when the distance of the height between spray nozzle and substrate was increasing.更多还原