PCD与CVD金刚石显微组织及使用特性分析

经对PCD与CVD金刚石厚膜显微组织的研究，发现气相沉积法生产的金刚石厚膜与PCD有着完全不同的组织形式。研制刀具并进行切削性能试验，验证了CVD金刚石厚膜刀具的切削适用范围，分析了它们在机械切削加工领域中的不同使用特性。     

CVD金刚石厚膜刀具的制造及应用

随着汽车、宇航、电子工业的发展,大量有色金属和新型材料的广泛应用,使金刚石切削刀具的需求量迅速增长。化学气相沉积(CVD)金刚石作为一种新型超硬刀具的材料,为金刚石刀具的应用开辟了新的途径。CVD金刚石刀具主要有两种类型:CVD金刚石薄膜涂层刀具和CVD金刚石厚膜焊接刀具。金刚石薄膜涂层与刀具衬底材料之间的     

CVD金刚石厚膜刀具的耐磨性试验

介绍了ＣＶＤ 金刚石刀具的特点,进行了ＣＶＤ 金刚石厚膜刀具与ＰＣＤ 刀具的耐磨性对比试验,结果表明ＣＶＤ 金刚石厚膜刀具的耐磨性明显优于ＰＣＤ 刀具,但韧性略低。     

CVD金刚石厚膜的制备及厚膜刀具制造技术

分析了沉积参数对合成金刚石厚膜质量的影响,提出了采用燃焰法沉积高质量金刚石厚膜的合理参数,介绍了金刚石厚膜的激光切割、焊接及刃磨加工特性。     

乙炔-氧气火焰沉积高质量、致密金刚石厚膜

通过分析了沉积温度、乙炔－氧气流量配比对金刚石厚膜质量的影响及高质量金刚石厚的生长过程。     

CVD金刚石刀具的研究进展与应用现状

金刚石膜是采用化学气相沉积的方法制备出来的一种全晶质多晶纯金刚石材料,是制造刀具的理想材料。本文对CVD金刚石涂层刀具与厚膜焊接刀具的研究进展与应用现状进行了简要的综述。     

CVD金刚石厚膜焊接刀具的试验研究

提出一种制作CVD金刚石厚膜焊接刀具的新工艺。采用电子辅助化学气相沉积法 (EACVD)制备直径10 0mm、厚度 0 8～ 1mm的金刚石厚膜 ;通过对金刚石刀头表面进行金属化处理 (化学气相沉积W膜 ) ,改善了金刚石的耐高温性及与低熔点合金焊料的浸润性 ,可在大气环境下实现金刚石刀头与刀架的焊接。车削试验结果表明 :用新工艺制作的金刚石刀具适用于精密加工     

金刚石工具的使用领域

金刚石工具在有色金属和耐磨材料的加工应用中,有出色的适应性。     

CVD金刚石厚膜焊接刀具的制造及切削性能

用于制造金属切削刀具的金刚石主要有四种类型：（1）天然单晶金刚石；（2）人工合成单晶金刚石；（3）聚晶金刚石复合片（PCD）；（4）化学气相沉积（CVD）金刚石膜。近年来，随着CVD金刚石工艺的发展，CVD金刚石对具的应用越来越广泛。CVD金刚石对具有两类：CVD金刚石薄膜涂层刀具和CVD金刚石厚膜焊接刀具。由于金刚石厚膜焊接刀具兼有单晶金刚石和金刚石薄膜涂层刀具的优点，从而具有广阔的应用前景。本文主要介绍金刚石厚膜的制备、厚膜刀具的制造及厚膜刀具的切削性能。     

CVD金刚石厚膜刀具切削性能的试验研究

分析了CVD金刚石厚膜刀具材料的性能特点 ,对CVD金刚石厚膜车刀进行了精密切削和难加工复合材料切削试验 ,结果表明 :CVD金刚石厚膜刀具加工铝合金的表面粗糙度可达Ra0 0 5 μm ;切削难加工复合材料时刀具耐磨性和使用寿命明显优于硬质合金刀具、PCBN刀具和PCD刀具     

Optical characteristics of silver film on the moth-eye structure

The development of coating optics to lower the reflected light and thereby to increase the optical efficiency of an optical system has been a very important issue for many years. Conventional solutions to this, such as multilayered alternation of high and low refractive index layers, often lead to an expensive coating process. Recently, the use of antireflection structured (ARS) surface, which is called “moth-eye structure”, has been proposed as an applicable option based on both the theoretical and experimental studies. In the current study, the experimental results of the reflectance and transmittance of two different thicknesses of silver films deposited on the moth-eye structure were carried out. The moth-eye structure arrays were fabricated by holographic exposure and photolithographic processes on the polymer film. The structure arrays were consisted of periodic length of about 300 nm, with the diameter of about 250 nm and the height of 150 nm. Compared with the silver coating film on the flat PET substrate, the optical property of the silver coating film on the moth-eye structure showed a better result for the anti-reflection application. The 25 nm-thick silver film on the moth-eye structure is suggested to be applied for the car window glass of antireflective films to obtain the high performance of heat insulation with acceptable transparency in the visible range.     

反吹气相色谱法快速分析煤气含量

论述采用双柱串联，六通阀进样，再利用反吹技术，成功分析了两种性质不同组份的混合气体的快速气相色谱法。     

Numerical analysis of Nd:YAG pulsed laser polishing CVD self-standing diamond film

Chemical vapor deposited(CVD) diamond film has broad application foreground in high-tech fields.But polycrystalline CVD self-standing diamond thick film has rough surface and non-uniform thickness that adversely affect its extensive applications.Laser polishing is a useful method to smooth self-standing diamond film.At present,attentions have been focused on experimental research on laser polishing,but the revealing of theoretical model and the forecast of polishing process are vacant.The paper presents a finite element model to simulate and analyze the mechanism of laser polishing diamond based on laser thermal conduction theory.The experimental investigation is also carried out on Nd:YAG pulsed laser smoothing diamond thick film.The simulation results have good accordance with the results of experimental results.The temperature and thermal stress fields are investigated at different incidence angles and parameters of Nd:YAG pulsed laser.The pyramidal-like roughness of diamond thick film leads to the non-homogeneous temperature fields.The temperature at the peak of diamond film is much higher than that in the valley,which leads to the smoothing of diamond thick film.The effect of laser parameters on the surface roughness and thickness of graphite transition layer is also carried out.The results show that high power density laser makes the diamond surface rapid heating,evaporation and sublimation after its graphitization.It is also found that the good polish quality of diamond thick film can be obtained by a combination of large incident angle,moderate laser pulsed energy,large repetition rate and moderate laser pulse width.The results obtained here provide the theoretical basis for laser polishing diamond film with high efficiency and high quality.     

相变区纳米硅氧薄膜的微观结构及光学特性

为了研究硅异质结太阳电池中纳米硅氧薄膜的光电特性,采用甚高频等离子体增强化学气相沉积技术制备了一系列不同晶态比例的nc-SiOx∶H薄膜,利用拉曼散射光谱(Raman)、傅里叶变换红外光谱(FTIR)、紫外可见透射光谱以及稳/瞬态光致发光谱等检测手段分别对薄膜的微观结构、键合配置,能带特征以及发光特性进行了表征。薄膜结构特征分析显示,随着氧掺入量的增加,薄膜由微晶向非晶转化,光学带隙逐渐增加,而处在相变区(晶化度约为10%,nc-Si尺寸约为3nm)的薄膜具有较高的中程有序度、较小的结构因子和较为致密的微观结构。薄膜稳/瞬态光致发光结果显示,一定量的氧掺入可以钝化缺陷、增强发光,而相变区薄膜的发光强度最大,表明较小尺寸的nc-Si具有较强的量子限制效应,nc-Si的量子限制效应发光是主要的载流子复合机制。     

Mechanical analysis of the blistering of a thin film deposited on a glassy polymer

In most cases, scratching of the surface of a polymeric glass elicits brittle behavior. A common way to improve the scratch resistance of a sensitive surface is to coat it with a thin film. Further work is required to explain the improvement in scratch resistance due to coating technique and predict the cracking in anti-scratch coatings. Moreover, the substrate/thin film adhesion must be well controlled and measurable. The present study contributes to these aims. Using a single-asperity scratching device allowing in situ observation of the scratch, the fracturing of a thin nano-composite coating deposited on a polycarbonate substrate was investigated under different conditions of temperature and scratching speed. Four types of fracture mechanisms were observed, depending on these two variables. A global energy balance model of the blistering process which is obtained for some experimental conditions permits one to determine the adhesion of the system. The adhesion can be measured by following the delaminated area (quantified by image analysis) as a function of the scratching distance during blistering. The particular case of an experimental stable blistering process was studied and the corresponding substrate/thin film adhesion was derived using the global energy balance model.     

Mechanical and tribological properties of vapour deposited low friction coatings on Ni plated substrates

Soft steel and aluminium substrates with load-carrying layers of electroplated nickel were coated with commercially available low friction vapour deposited coatings. The mechanical and tribological properties of the coating and substrate composites were evaluated with special emphasis on the influence of the nickel layer. Two different thicknesses of the intermediate load-carrying nickel layer were tested. The samples were evaluated regarding friction and sliding wear, abrasive wear, hardness and elastic modulus, morphology and coating thickness and adhesion between substrate and coating. It was found that all the evaluated low friction coatings were possible to be successfully deposited on the intermediate nickel layer. A relatively thick intermediate nickel layer is a promising candidate for improvement of the load-carrying capacity.     

The slurry erosive wear of physically vapour deposited TiN and CrN coatings under controlled corrosion

The erosion-corrosion of mild steel (BS6323), in the presence and absence of physically vapour deposited (PVD) TiN and CrN coatings, was studied, in comparison with that of AISI 304 stainless steel, in an aqueous alkaline slurry solution containing alumina particles. The influence of applied potential and particle velocity on the total erosion-corrosion loss was examined, and the respective corrosion and erosion damage (both contributing to the overall weight loss) then assessed by means of microscopical investigation of the morphology of the damaged surface, and subsequently evaluated quantitatively. The superior erosion-corrosion resistance of both the coatings compared to that of the uncoated mild and stainless steels was shown to be due to their resistance to both wear and corrosion. According to the detailed corrosion mechanisms revealed and different responses to wear, schematic diagrams were proposed to outline the main features of the corrosion-erosion process and the individual roles of erosion and corrosion. Discrete differences, in terms of the respective erosion and corrosion processes, between the TiN and CrN coatings, and between the mild and stainless steels, were also investigated and discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Gas film disturbance characteristics analysis of high-speed and high-pressure dry gas seal

The dry gas seal(DGS) has been widely used in high parameters centrifugal compressor, but the intense vibrations of shafting,especially in high-speed condition, usually result in DGS's failure. So the DGS's ability of resisting outside interference has become a determining factor of the further development of centrifugal compressor. However, the systematic researches of which about gas film disturbance characteristics of high parameters DGS are very little. In order to study gas film disturbance characteristics of high-speed and high-pressure spiral groove dry gas seal(S-DGS) with a flexibly mounted stator, rotor axial runout and misalignment are taken into consideration, and the finite difference method and analytical method are used to analyze the influence of gas film thickness disturbance on sealing performance parameters, what's more, the effects of many key factors on gas film thickness disturbance are systematically investigated. The results show that, when sealed pressure is 10.1MPa and seal face average linear velocity is 107.3 m/s, gas film thickness disturbance has a significant effect on leakage rate, but has relatively litter effect on open force; Excessively large excitation amplitude or excessively high excitation frequency can lead to severe gas film thickness disturbance; And it is beneficial to assure a smaller gas film thickness disturbance when the stator material density is between 3.1 g/cm~3 to 8.4 g/cm~3; Ensuring sealing performance while minimizing support axial stiffness and support axial damping can help to improve dynamic tracking property of dry gas seal. The proposed research provides the instruction to optimize dynamic tracking property of the DGS.     

CVD金属石膜刀具的制造技术及其应用

主要论述了CVD金刚石厚膜刀具制造过程中的几个关键工艺,包括切割、焊接、抛光和刃磨等,介绍了CVD金刚石膜刀具加工复合材料的实验研究。     

Origin of phase shift in atomic force microscopic investigation of the surface morphology of NR/NBR blend film

Atomic force microscopy (AFM) was used to study the morphology and surface properties of NR/NBR blend. Blends at 1/3, 1/1 and 3/1 weight ratios were prepared in benzene and formed film by casting. AFM phase images of these blends in tapping mode displayed islands in the sea morphology or matrix-dispersed structures. For blend 1/3, NR formed dispersed phase while in blends 1/1 and 3/1 phase inversion was observed. NR showed higher phase shift angle in AFM phase imaging for all blends. This circumstance was governed by adhesion energy hysteresis between the device tip and the rubber surface rather than surface stiffness of the materials, as proved by force distance measurements in the AFM contact mode.