Dispersion of Micro Diamond Particles in Electroless Nickel Solution

The dispersion behavior of micro-diamond particles ranging from 0 to 0.5 micron was compared between in DI water and in electroless nickel solution. The effects of the concentration of electroless solution, temperature, ultrasonic treatment, stirring speed, and baffles on the size distribution of micro diamond particles in electroless nickel solution were studied. Results show that the dispersion of micro diamond particles in DI water is obviously superior to that in electroless nickel solution. Micro diamond particles agglomerate evidently when the concentration of electroless solution Velect：VDI in dispersion media exceeds 5%0. Diamond particles agglomerate more and more seriously with the increase of the ion concentration. Applying ultrasonic, increasing stirring speed and adding baffles are helpful to improving the dispersion of diamond particles in the electroless nickel solution and its uniform distribution in the Ni-P coating.

CVD Micro-diamond Coated Tool Lapping with Sapphire Wafer

Micro-diamond films were prepared on YG6 substrate by hot filament chemical vapor deposition method.An innovative micro-diamond coated tool was used to the lap sapphire wafer.The effect of load,rotating speed,and lapping time on material removal rate(MRR)and surface roughness was investigated.The results showed that the best process parameters were 3N,100r/min and 15 min.The surface quality of sapphire improved significantly after lapping.The coating after lapping adhered well and did not show any peeling.The innovative micro-diamond coated tool was feasible and suitable for the lapping of the single crystal sapphire wafer.

Wear characteristics of Ⅴ shape diamond tool for micro prism pattern with Al alloys

The ultra-precision machining process using a single crystal diamond tool has been mainly used for machining molds of optical components.Since the micro patterns of various shapes having excellent surface roughness can be machined by using ultra-precision machine tools,the micro pattern on a large light guide plate (LGP) is mainly machined using a diamond tool.The tool wear occurs due to long machining distances and time while machining a large-area LGP mold.The deformation and dimensional error of micro pattern are caused by tool wear,as a result,the light efficiency of LGP declines.The characteristics of tool wear should be analyzed in order to precisely machine large-area LGP mold from all sorts of materials.The experiments were performed in order to compare wear characteristics of a V90° diamond tool using Al3003,5052,6061 and 7075.The prism pattern of depth 10 μm was machined in order to analyze characteristics of tool wear according to machining distances (0.5,1 and 1.5 km).The effects of tool wear on pattern shape were analyzed by applying overlapped cutting depths (Rough machining is (10+8+7) μm and Finish machining is (5+3+2+1) μm) by continuously machining a prism pattern of W shape of 25 μm in depth.

Micro/nano Indentation and Single Grit Diamond Grinding Mechanism on Ultra Pure Fused Silica

The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced damage in the grinding in order to reduce or eliminate the subsurface damage.The brittle/ductile transition behavior of optical glass materials and the wear of diamond wheel are the most important factors for ductile grinding of optical glass.In this paper,the critical brittle/ductile depth,the influence factors on brittle/ductile transition behavior,the wear of diamond grits in diamond grinding of ultra pure fused silica（UPFS） are investigated by means of micro/nano indentation technique,as well as single grit diamond grinding on an ultra-stiff machine tool,Tetraform ＂C＂.The single grit grinding processes are in-process monitored using acoustic emission（AE） and force dynamometer simultaneously.The wear of diamond grits,morphology and subsurface integrity of the machined groves are examined with atomic force microscope（AFM） and scanning electron microscope（SEM）.The critical brittle/ductile depth of more than 0.5 μm is achieved.When compared to the using roof-like grits,by using pyramidal diamonds leads to higher critical depths of scratch with identical grinding parameters.However,the influence of grit shapes on the critical depth is not significant as supposed.The grinding force increased linearly with depth of cut in the ductile removal regime,but in brittle removal regime,there are large fluctuations instead of forces increase.The SEM photographs of the cross-section profile show that the median cracks dominate the crack patterns beneath the single grooves.Furthermore,The SEM photographs show multi worn patterns of diamond grits,indicating an inhomogeneous wear mechanism of diamond grits in grinding of fused silica with diamond grinding wheels.The proposed research provides the basal technical theory for improving the ultra-precision grinding of UPFS.

Deformation Analysis of Micro/Nano Indentation and Diamond Grinding on Optical Glasses

The previous research of precision grinding optical glasses with electrolytic in process dressing （ELID） technology mainly concentrated on the action of ELID and machining parameters when grinding, which aim at generating very ＂smoothed＂ surfaces and reducing the subsurface damage. However, when grinding spectrosil 2000 and BK7 glass assisted with ELID technology, a deeply comparative study on material removal mechanism and the wheel wear behaviors have not been given yet. In this paper, the micro/nano indentation technique is initially applied for investigating the mechanical properties of optical glasses, whose results are then refereed to evaluate the machinability. In single grit diamond scratching on glasses, the scratching traces display four kinds of scratch characteristics according to different material removal modes. In normal grinding experiments, the result shows BK7 glass has a better machinability than that of spectrosil 2000, corresponding to what the micro/nano indentation vent revealed. Under the same grinding depth parameters, the smaller amplitude of acoustic emission （AE） raw signals, grinding force and grinding force ratio correspond to a better surface quality. While for these two kinds of glasses, with the increasing of grinding depth, the variation trends of the surface roughness, the force ratio, and the AE raw signals are contrary, which should be attributed to different material removal modes. Moreover, the SEM micrographs of used wheels surface indicate that diamond grains on the wheel surface after grinding BK7 glass are worn more severely than that of spectrosil 2000. The proposed research analyzes what happened in the grinding process with different material removal patterns, which can provide a basis for producing high-quality optical glasses and comprehensively evaluate the surface and subsurface integrity of optical glasses.

Heat Resistant Properties of Some Elements-Incorporated Diamond-Like Carbon Films and Their Trial Applications for Micro End Mill Coatings

In this article, the results obtained from a study carried out on the some elements-incorporated diamond-like carbon (DLC) films are reported. All the films were deposited using plasma-based ion implantation (PBII) technique. The deposited films were annealed at 400℃, 650℃ and 900℃ in an air atmosphere for 1 hour. The effects of adding hydrogen, silicon/oxygen and silicon/nitrogen into the DLC film on chemical composition, friction coefficient and corrosion resistance were investigated. The films coated micro end mills performance was also assessed. The results indicate that all the films showed almost constant atomic contents of C, Si, O and N until annealing at 400℃. However, the films were completely destroyed at 650℃ with the increased Si and O contents, while the C content decreased. The incorporation of silicon/oxygen and silicon/nitrogen into the DLC exhibited lower values of friction coefficients than the hydrogenated DLC (DLC and H-DLC) before and after annealing at 400℃, whereas all the films presented the same values of friction coefficients after annealing at 650℃ due to the completely destroy of the films. Furthermore, the incorporation of silicon/nitrogen into the DLC also exhibited better corrosion resistance and unbroken micro end mills performance on their surfaces. Thus, the incorporation of silicon/nitrogen into the DLC film can be considered beneficial in improving the micro end mills performance.

Investigation on the priming effect of a CVD diamond microdosimeter

CVD diamond microdosimeter is an ideal substitute of common Si.GaAs detector for extremely strong radiation experimental environment due to its high band gap energy, fast charge collection, low dielectric constant and hardness. In order to improve its character, a CVD diamond microdosimeter was irradiated by a proton dose of 46 Gy, and a lateral micro-ion beam induced charge (IBIC) technique was utilized to characterize it in low beam current (～fA). It was clearly shown that charge collection efficiency and energy resolution were greatly improved after proton irradiation of that dose. Moreover, the homogeneities of both its counting performance and collection efficiency were enhanced. Proton irradiation of 46 Gy has been proved to be an effective way to prime a CVD diamond.

芯片研制用微纳米尺度温度测量方法及其展望

微纳米尺度温度测量,提供微小尺度区域的高精度温度信息。然而现有的测温技术无法满足芯片性能日益提升的需求,例如以热电偶等为代表的接触式测温具有较高的测量精度,但其响应速率慢难以实现宽场热成像;以红外辐射等为代表的非接触式测温可实现芯片表面的快速热场测量,但测温精度较低、空间分辨率受到波长的限制。因此传统测温方法难以同时满足高精度、微纳米尺度的快速温度测量,亟需寻求新的测温技术。随着量子精密测温技术的发展,基于固态量子自旋效应的金刚石带负电的氮-空位(negatively charged nitrogen-vacancy,NV-)色心测温技术有望解决上述问题,突破现有微纳米尺度测温在芯片研制方面的应用瓶颈。鉴于此,首先综述对比了现有芯片用测温技术的特点和发展现状,而后调研分析了金刚石NV色心测温计量特性及小型化、集成化技术发展趋势,并展望了金刚石NV色心测温在芯片研制领域的技术优势和应用前景,提出其发展面临的挑战。

KDP晶体微塑性域增强金刚石切削方法研究

针对KDP在SPDT切削过程中容易产生凹坑、划痕、裂纹等表面缺陷问题,提出利用热激励的方式增大KDP晶体塑性切削域深度,降低各向异性、机床运动误差、环境振动等因素对加工过程的影响,进而提高SPDT切削加工过程稳定性的方法。通过纳米压痕试验获得了KDP晶体表面在不同温度状态下的硬度和脆塑性转变深度变化规律,并在SPDT机床上采用金刚石刀具开展了KDP晶体飞切划痕实验,进一步验证了适当提高KDP晶体温度可以增大KDP晶体脆塑性转变临界切削深度。在此基础上,对KDP晶体开展了不同温度状态下的切削实验,实验结果表明在相同工艺参数下,随着温度的升高,表面粗糙度Sa值从3.2nm降低至1.6nm。

Nano-diamond/Ni复合电刷镀层的组织形貌的研究

以45#钢为基体,制备了普通镍镀层和nano-diamond/Ni复合刷镀层,采用扫描电镜、能谱仪、X射线衍射仪和金相显微镜等设备对比研究了两种镀层的组织形貌。金相显微镜和扫描电镜分析结果表明,与普通镍镀层相比,nano-diamond/Ni复合刷镀层的表面更加平整、致密,组织更加细化;nano-dia-mond/Ni复合刷镀层表面呈典型的"菜花头"形状,弥散分布的纳米金刚石被镍包裹。能谱仪分析结果表明,nano-diamond/Ni复合刷镀层中纳米颗粒特征元素C的质量分数为7.37%。X射线衍射分析结果表明,随着纳米金刚石加入量的增加,镀层表面晶粒尺寸逐渐减小。

增材制造钛合金的微铣削加工试验

增材制造(Additive manufacturing,AM)技术制备的钛合金部件在航空航天领域具有广泛的用途,对增材制造钛合金精密零部件而言,铣削、抛光等后处理加工是必不可少的工序。本文选用聚晶金刚石(Polycrystalline diamond,PCD)微铣刀对锻造钛合金、激光选区熔化(Selective laser melting,SLM)技术制备的未经过热处理和经过热处理的钛合金进行微铣削试验,研究了3种不同制造工艺的钛合金材料的微铣削加工性能。结果表明:SLM-热处理钛合金的铣削力最大,这与其材料硬度最高有关。微铣削过程中,所有钛合金材料的逆铣侧顶端毛刺尺寸均要大于顺铣侧顶端毛刺尺寸。在不同制造工艺的钛合金材料中,SLM-钛合金生成的顶端毛刺宽度最小,这与其塑性最差有关。SLM-热处理钛合金获得的表面质量最好,这不仅与材料的硬度和塑性有关,同时还受到孔隙度的影响。

金刚石色心调控及光学谐振器的研究进展

金刚石因其优异的光学特性和色心发射器而被应用于光子器件领域。光学谐振器是一种微纳米光学结构,基于有限模体积内的光-物质相互作用增强,能够将金刚石色心的发射与谐振器的增强效应相结合,有选择性地增强色心的发射,用于在光子电路中提供稳定且强度充足的光学信号。近年来,金刚石微纳加工技术的发展推动了金刚石光学谐振器的研究和应用。本文总结了金刚石光学谐振器的研究现状,概述了金刚石的基本性质、合成与加工方法,介绍了金刚石色心的生成以及其与光学谐振器的耦合原理,梳理了三种不同类型的金刚石光学谐振器的研究进展,并对未来金刚石光学谐振器的发展进行了展望。

新型KTN衬底上生长金刚石及其光催化性能研究

采用微波等离子体化学气相沉积技术,以钽铌酸钾(KTa1-xNbxO3,简称KTN)作为衬底,生长高质量金刚石薄膜。用X射线衍射仪、扫描电子显微镜和拉曼光谱仪观察并分析金刚石薄膜的表面形貌和微观结构,并研究样品的光催化性能。结果表明:金刚石生长过程中形成了碳化钽过渡层;随着生长时间延长金刚石质量不断提高;所有样品均表现出良好的降解罗丹明B的能力,其中生长时间为12 h的样品对罗丹明B的降解效率提高了0.29倍,与生长时间为3 h的样品相比其降解效率提高了1.6倍。本研究为生长多晶金刚石提供新型衬底,并探索金刚石在光催化方面的应用。

基于微转印技术的金刚石上硅材料制备与表征

硅基电子器件在高温、高功率、射频领域应用时面临热管理的挑战。为解决其散热和射频损耗问题,采用微转印技术在常温常压下将单晶硅薄膜转移至金刚石衬底上,制备出新型集成电路材料——金刚石上硅(SOD)。实验结果表明,转移的单晶硅薄膜表面平整、无明显损伤,保持了其原有的完整性。透射电子显微镜的观察结果进一步显示,金刚石与硅之间的界面结合紧密,不存在纳米级间隙。界面热阻测试结果显示,SOD样品的有效界面热阻(R_(EI))为30.30m^(2)·K/GW,明显优于SOI样品的R_(EI)(376.78m^(2)·K/GW)。该研究验证了SOD材料在热管理方面的潜力,也为未来新型硅基器件的设计与应用提供了参考。

基于MD模拟的低能FIB辐照金刚石靶材亚表层损伤形成机理研究

聚焦离子束(focused Ion beam,FIB)作为一种用于金刚石微铣刀的特种加工方式,其引发的损伤程度直接关联到刀具的加工性能和寿命。课题组采用LAMMPS软件进行分子动力学(Molecular Dynamics,MD)模拟,结合SRIM软件的分析结果,探究单晶金刚石亚表层损伤的形成机理和入射离子能量对损伤深度和范围的影响。模拟结果表明:随着入射离子能量的提升,离子束在材料内的渗透深度及引起的非晶层和点缺陷损伤均有所增加;进一步的研究发现损伤形成过程中材料局部温度的上升可能诱发自退火现象,且与离子入射能量成正比,该现象对于理解聚焦离子束加工引起的损伤有着至关重要的意义;而势能的变化与损伤形成之间的显著对应关系揭示了第一邻近原子的势能明显高于第二邻近原子,进而高于Other类型原子,这一发现有助于深入理解损伤形成的微观过程。因此,精确控制入射能量是实现金刚石材料高精度聚焦离子束加工的关键,且对自退火效应和势能变化的研究对损伤监控与控制同样重要。

Diamond软件在晶体结构微观对称性教学中的应用

微观对称性是晶体结构教学的重要内容之一,是点对称要素和平移对称要素的组合,称为空间群。本文采用Diamond软件构建Pm3m、Fm3m、Fd3m和F43m等四种立方晶系常见空间群的晶体结构模型,分析了空间群符号中各字母和数字所表达的含义,并展示了对称要素和对称操作。以直观的形式将抽象的内容具体化,有利于学生更好的理解和掌握空间群的概念,增强教学效果。

Optical and electronic performances of CVD diamond film andits applications in radiation detectors

The outstanding properties of CVD diamond film such as electronic, optical, thermal and mechanical and the high radiation hardness have made it an ideal candidate material for radiation detectors in severe environments. Fabrication of ＇detector grade＇ CVD diamond films and development of CVD diamond detectors have been leading edge subjects. Micro-strip gas chamber （MSGC） fabricated on CVD diamond substrate would overcome the charge-up effect and the substrate instability, which has been a hotspot in the research of gas detectors.

Novel Pretreatment of Hard Metal Substrate for Better Performance of Diamond Coated Cutting Tools

A surface engineering approach for a novel pre-treatment of hard metal tool substrate for optimum adhesion of diamond coatings is presented. Firsfly, an alkaline solution was used to etch the WC grains to generate a rough surface for better mechanical interlocking. Subsequently, surface Co was removed by etching in acid solution. Then the hard metal substrate was boronized to form a compound interlayer which acted as an efficient diffusion barrier to prevent the outward diffusion of Co. Novel nano-microcrystalline composite diamond film coatings with a very smooth surface was deposited on the surface engineering pre-treated hard metal surface. Promising results of measurement in adhesion strength as well as field cutting tests have been obtained.

Influence of tool deflection on micro channel pattern of 6:4 brass with rectangular tool

Machining experiment of micro channel structure with 6:4 brass was carried out by shaping process using a single crystal diamond tool. FEM simulation using solid cantilever beam model was analyzed. In result of experiment, tool deflection is observed as machining characteristics through result of experiments such as surface roughness, cutting force and burr formations. And the influence of tool deflection is experimentally proved.