纳米金刚石用作磁头抛光材料的研究

研究了油基金刚石悬浮液用作磁头抛光材料的抛光性能,用原子力显微镜和扫描电子显微镜观察了磁头抛光后的表面。结果表明,纳米金刚石是一种理想的抛光材料,用于超高精度表面加工,其表面抛光质量要明显优于单用国外同类金刚石悬浮液抛光磁头的质量,纳米颗粒的作用十分明显,证实了纳米材料可用超精抛光材料。     

水介质中纳米金刚石表面改性研究

对纳米金刚石在水介质中的分散进行了探讨,利用机械力和化学力共同作用,对纳米金刚石表面进行改性,从而实现纳米金刚石在水介质中的分散和稳定,采用不同的机械化学处理工艺,可以使得体系在酸性和碱性介质条件下均保护良好的分散。对表面改性过程进行了机理分析。     

金刚石纳米颗粒合成技术及应用研究进展

金刚石纳米颗粒粉体材料作为一种具有超硬特性、化学稳定性、良好导热性和生物相容性等优良性能的重要功能材料,有望在超精密抛光、复合镀工艺、场发射材料、隐身材料、润滑油、涂料、医疗等领域得到广泛应用[1]。目前,金刚石纳米颗粒粉体工业化规模合成的方法有:静压合成金刚石单晶粉碎、动压冲击合成金刚石聚晶和爆轰法合成纳米金刚石团簇。结合应用需求进行金刚石颗粒与形貌的再加工、表面官能化,实现颗粒在应用介质中的均匀与稳定分散,是金刚石纳米     

纳米金刚石颗粒的长大实验研究

本文研究了炸药爆轰合成的纳米金刚石粉的小颗粒在高温（－1000K）和高压（5．2GPa)条件下的长大行为。将纳米金刚石粉放入特制的模具中压制成小圆片,将纳米金刚石小圆片相互叠加起来放相钼套中,压实,然后将钼套置于石墨套中再放到叶蜡石块中,于高温高压下进行长大实验。实验结果表明,在此高温高压条件下,纳米金刚石粉没有石墨化;纳米金刚石粉的纳米颗粒长大,可长成1微米尺寸的金刚石颗粒（温度为1000K左右）,这一现象表明,纳米金刚石颗粒表面的活性使得它可以在较低的温度长成较大的金刚石颗粒。     

铬-纳米金刚石复合镀影响因素的研究

在对市售纳米金刚石进行适当的机械化学改性、分散及分级,制得粒度分布在150nm 以内、浓度可调、分散稳定、不含污染镀液成分的复合镀用纳米金刚石悬浮液的基础上,研究了工艺条件、纳米金刚石粒度和表面状态、镀液中添加表面活性剂对铬-纳米金刚石复合镀镀层性能的影响。结果表明,常规硬铬电镀工艺同样适合于铬-纳米金刚石复合镀;纳米金刚石团聚体解聚、粒度分布均匀和在镀液中稳定分散是得到高性能镀层的前提条件;颗粒能否在阴极粘附足够长的时间形成强吸附是颗粒沉积的关键,标准镀液中加入纳米金刚石镀层显微硬度反而降低,添加表面活性剂镀液中的复合镀层晶粒明显细化、显微硬度提高可达35%。     

纳米颗粒分散方法对电刷镀复合镀层组织及性能的影响

为了解决镀液中纳米颗粒的团聚问题,采用高能机械化学法对纳米颗粒进行了分散,在扫描电镜、显微硬度计、球-盘式磨损试验机上对比考察了机械搅拌法和高能机械化学分散法对电刷镀液中纳米颗粒分布和复合镀层组织、显微硬度及含磨料油润滑条件下磨损性能的影响.结果表明,高能机械化学分散法较好地解决了纳米颗粒分散的难题,与机械搅拌法相比,高能机械化学分散法制备的电刷镀液中纳米颗粒分散均匀、团聚少、稳定悬浮时间长,复合镀层中纳米颗粒含量高,镀层组织细小、致密,显微硬度高,含磨料油润滑条件下的耐磨性能好.     

镍 -纳米氧化铝复合电镀液的制备及影响因素研究

性质均匀稳定的镍/纳米颗粒复合镀液是制备镍/纳米复合镀层的物质和工艺基础.在瓦特镀镍溶液中加入纳米Al2O3粉末,混合液静置10 h后,因颗粒沉淀而产生不同程度的分层,通过比色法研究了分散剂、分散形式、镀液pH值对纳米Al2O3粉末在镀液中均匀稳定分散的影响.结果表明,在镀液中加入适量的聚羧酸铵、柠檬酸三铵或十六烷基三甲基溴化铵分散剂,并通过超声分散,可得到稳定分散10 h以上的复合电镀液.原子力显微镜分析表明,复合镀液中纳米颗粒的平均尺寸为63 nm,略大于其原料颗粒的尺寸(40 nm),大部分的纳米颗粒在复合镀液中能实现高度分散.     

非水介质中纳米金刚石的改性、分散与应用

开展纳米金刚石在非水介质中应用的前提是其在介质中的良好分散与稳定.鉴于此,综述了非水介质中纳米金刚石改性与分散研究进展,以及相关应用现状和前景.     

改性纳米金刚石增强增韧医用口腔复合树脂的研究

以爆轰法合成的纳米金刚石作为填料,加入到双酚A型口腔用光固化复合树脂中,研究了纳米金刚石对树脂性能的影响.金刚石用硅烷偶联剂进行表面改性.结果发现:偶联剂化学接枝到金刚石表面,改性后的金刚石在乙醇中的分散稳定性得到提高;加入0.2%(质量分数)的改性纳米金刚石后,复合树脂的挠曲强度和硬度分别提高35.4%和29.8%,改性金刚石的增强作用明显优于未经改性的金刚石;同时金刚石的加入也改善了树脂的韧性.     

金刚石涂层激光抛光机理及加工工艺研究进展

CVD金刚石涂层表面粗糙度高、颗粒大,不能满足精密和超精密加工的要求,在一定程度上制约了其发展和应用,降低CVD金刚石涂层表面粗糙度是迫切需要解决的难题.阐述了激光抛光CVD金刚石涂层机理,对比了微观抛光和宏观抛光的差异,总结了国内外激光抛光金刚石涂层研究进展,探讨了 目前激光抛光金刚石涂层的挑战和亟待解决的难点.     

CVD金刚石膜高效超精密抛光技术

CVD金刚石膜作为光学透射窗口和新一代计算机芯片的材料,其表面必须得到高质量抛光,但是现存方法难以满足既高效又超精密的加工要求.本文提出机械抛光与化学机械抛光相结合的方法.首先,采用固结金刚石磨料抛光盘和游离金刚石磨料两种机械抛光方法对CVD金刚石膜进行粗加工,然后采用化学机械抛光的方法对CVD金刚石膜进行精加工.结果表明,采用游离磨料抛光时材料去除率远比固结磨料高,表面粗糙度最低达到42.2 nm.化学机械抛光方法在CVD金刚石膜的超精密抛光中表现出较大的优势,CVD金刚石膜的表面粗糙度为4.551 nm.     

Fabrication and Characterization of FeNiCr Matrix-TiC Composite for Polishing CVD Diamond Film

Dynamic friction polishing (DFP) is one of the most promising methods appropriate for polishing CVD diamond film with high efficiency and low cost.By this method CVD diamond film is polished through being simply pressed against a metal disc rotating at a high speed utilizing the thermochemical reaction occurring as a result of dynamic friction between them in the atmosphere.However, the relatively soft materials such as stainless steel, cast iron and nickel alloy widely used for polishing CVD diamond film are easy to wear and adhere to diamond film surface, which may further lead to low efficiency and poor polishing quality.In this paper, FeNiCr matrix-TiC composite used as grinding wheel for polishing CVD diamond film was obtained by combination of mechanical alloying (MA) and spark plasma sintering (SPS).The process of ball milling,composition, density, hardness, high-temperature oxidation resistance and wear resistance of the sintered piece were analyzed.The results show that TiC was introduced in MA-SPS process and had good combination with FeNiCr matrix and even distribution in the matrix.The density of composite can be improved by mechanical alloying.The FeNiCr matrix-TiC composite obtained at 1273 K was found to be superior to at 1173 K sintering in hardness, high-temperature oxidation resistance and wearability.These properties are more favorable than SUS304 for the preparation of high-performance grinding wheel for polishing CVD diamond film.     

新型单组分喷涂式纳米防雾滴剂的研制

介绍一种用于聚乙烯棚膜喷涂式的纳米防雾滴剂.其特点为:单组分的纳米无机粒子与复合表面活性剂的分散液,其喷涂于聚乙烯棚膜内表面可达到防雾滴功效,持效期可达到8个月以上.     

单晶金刚石机械研磨结合化学辅助机械抛光组合加工工艺

单晶金刚石因具有最高的硬度和最低的摩擦系数常被用来制备超精密刀具,而表面粗糙度是影响刀具寿命的重要指标.提出采用机械研磨结合化学辅助机械抛光的组合工艺抛光单晶金刚石.实验优化并确定的加工工艺如下:先用5μm和2μm金刚石粉研磨单晶金刚石表面,然后采用化学机械的方法去除机械研磨带来的损伤.用该工艺抛光单晶金刚石,表面粗糙度Ra可达0.8 nm(测量区域70μm×53μm).表面拉曼光谱分析表明化学机械抛光的表面只有1 332 cm-1拉曼峰.     

Effect of slurry composition on the chemical mechanical polishing of thin diamond films

Nanocrystalline diamond (NCD) thin films grown by chemical vapour deposition have an intrinsic surface roughness, which hinders the development and performance of the films’ various applications. Traditional methods of diamond polishing are not effective on NCD thin films. Films either shatter due to the combination of wafer bow and high mechanical pressures or produce uneven surfaces, which has led to the adaptation of the chemical mechanical polishing (CMP) technique for NCD films. This process is poorly understood and in need of optimisation. To compare the effect of slurry composition and pH upon polishing rates, a series of NCD thin films have been polished for three hours using a Logitech Ltd. Tribo CMP System in conjunction with a polyester/polyurethane polishing cloth and six different slurries. The reduction in surface roughness was measured hourly using an atomic force microscope. The final surface chemistry was examined using X-ray photoelectron spectroscopy and a scanning electron microscope. It was found that of all the various properties of the slurries, including pH and composition, the particle size was the determining factor for the polishing rate. The smaller particles polishing at a greater rate than the larger ones.     

Silica based polishing of {100} and {111} single crystal diamond

Diamond is one of the hardest and most difficult to polish materials. In this paper, the polishing of {111} and {100} single crystal diamond surfaces by standard chemical mechanical polishing, as used in the silicon industry, is demonstrated. A Logitech Tribo Chemical Mechanical Polishing system with Logitech SF1 Syton and a polyurethane/polyester polishing pad was used. A reduction in roughness from 0.92 to 0.23 nm root mean square and 0.31 to 0.09 nm rms for {100} and {111} samples respectively was observed.     

纳米粉体在液相中的分散和稳定

从理论上分析了纳米粉体在液相中的分散过程和稳定机理,将获得稳定纳米粉体分散液分为分散和稳定2个过程,重点考虑纳米颗粒的表面自由能对纳米粉体分散的影响以及纳米颗粒之间的相互作用能对分散液稳定所起的作用.在此基础上,研究了提高分散液稳定性的条件和措施.     

复合抛光对 CVD金刚石薄膜表面光洁度的改进研究

采用激光抛光和热化学抛光相结合的方法，对通过热丝CVD方法生长的金刚石薄膜进行了复合抛光处理．并利用X射线衍射仪（XRD）、拉曼光谱仪（Raman）、扫描电子显微镜（SEM）和原子力显微镜（AFM）对金刚石薄膜进行了表征．结果表明，所合成的金刚石薄膜是高质量的多晶（111）取向膜；经复合抛光后，金刚石薄膜的结构没有因抛光而发生改变，金刚石薄膜的表面粗糙度明显降低，光洁度大幅度提高，表面粗糙度Ra在100nm左右，基本可以达到应用的要求．     

Particle size and surfactant effects on chemical mechanical polishing of glass using silica-based slurry

This study explores the effect of particle size and surfactant on the chemical mechanical polishing (CMP) of glass using colloidal silica-based slurry. It was found that the material removal rate strongly depends on the particle size and the types of surfactants and that the rms roughness was independent of particle size and correlated to surfactants. On the basis of polishing results, it was concluded that the main polishing mechanism was changed from indentation mechanism to surface-area mechanism, with the variation of particle size. In addition, the molecular structure, charge type, and lubricating effect of the surfactants play an important role in the dispersion of abrasive particles and in the CMP performance.     

辐照过程中He对ODS合金中氧化物的影响EI北大核心CSCD

研究辐照下He在氧化物弥散强化材料中小于5nm的氧化物颗粒的稳定性。在有He环境下,对14YWT氧化物弥散强化材料进行高温离子辐照。采用三维原子探针(APT)对辐照前后样品中的氧化物颗粒的大小、密度、成分以及其空间分布进行分析。结果表明:小于5nm的弥散氧化物颗粒主要是由Y和Ti的氧化物组成,在辐照前后其成分、尺寸和空间分布无明显变化,说明在600℃高温重离子辐照过程中,在有He环境下铁素体ODS材料中弥散氧化物颗粒仍具有良好的稳定性。