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采用片状铁基触媒借鉴粉末工艺合成金刚石 总被引:4,自引:0,他引:4
以单质金属粉为原料,采用粉末冶金方法制备了片状铁基触媒,并借鉴目前金刚石工业中最为常用的粉末触媒组装方式及合成工艺在高温高压下进行了金刚石合成试验.试验获得了粒径为300~500μm,具有六-八面体外形,形态完整,质量较高的立方金刚石单晶.检测发现,其主要性能指标均超过机械行业标准《人造金刚石技术条件》(JB/T7989-1997)对锯片级金刚石的技术要求,评级可在SMD30以上.同时,还具有较小的磁性和优于一般金刚石的热稳定性.试验验证了采用单质金属粉合成优质金刚石的可能性,有望进一步简化触媒制备工艺,降低金刚石的生产成本. 相似文献
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等离子喷涂羟基磷灰石涂层的晶化及其结构特征 总被引:3,自引:0,他引:3
Phase compositions, function group and surface morphology of recrystallized plasma sprayed hydroxyapatite (HA) coatings were examined by means of X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), Raman spectra, scanning electron microscope (SEM) and electron probe microanalyzer (EPMA). The results show that the structural integrity of HA was almost completely restored after the heat treatment of (600~700℃)×2h. Temperatures above this value were unfavorable to the restoration of OH- and crystallinity. The recrystallizing treatment caused amorphous and decomposed phases transform into crystalline HA with a very small amount of CaO retained in coating. Under 500℃, longer keeping time led to a gradual increase of crystallinity, however, under 600℃, the crystallinity showed no obvious changes with decreased CaO content. Meanwhile, nanometer hydrox-yapatite crystals with dot-like, polyhedral, acerous and effloresent shapes and a average size of 100nm originated in the coatings. 相似文献
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Carbide Identification in Different Regions of a Thin Metal Film Covering on an HPHT As-Grown Diamond Single Crystal from Ni-Mn-C System 总被引:5,自引:0,他引:5 下载免费PDF全文
Diamond single crystals were synthesized in the presence of NI-Mn catalyst under high temperature and high pressure(HPHT).A thin metal film covering on as-grown diamond formed during diamond growth was examined using transmission electron microscopy.It was shown that phase compositions of the region near the as-grown diamond are different form those of other regions in the film. 相似文献
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采用场发射扫描电子显微镜(FESEM),研究了铁基金属包膜界面及其断面的精细结构。结果表明:包膜(100)界面有纳米级的棱锥状突起,包膜(111)界面上分布着锯齿状的台阶;金属包膜近触媒侧的界面断面表层分布着台阶形貌的胞状突起;断面其它断层断口呈现脆性断裂特征,断层表面分布着团簇状的纳米颗粒。分析认为:包膜界面的不同形貌与片状金刚石结晶基元的不同生长过程有关;由于包膜内脆性碳化物的存在,包膜断面呈现脆性断口特征;断面上分布的纳米级颗粒可能是金属成分的共晶析出产物。 相似文献