bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on Polishing Characteristics of Ultrasonic- Magnetorheological Compound Finishing
Authors: Zhang Fei Hu , Yu Xing Bin , Zhang Yong , Lin Yong Yong , Luan Dian Rong
Published: September 2009

Concave aspheric surface with small radius is difficult to be fabricated by most of existing technologies for optical manufacture. Ultrasonic- magnetorheological compound finishing (UMC finishing) is a new technology for the ultra-precision machining of concave aspheric surface with small radius and freeform surface. The principle and experimental deviece used in UMC finishing are introduced. Main technological parameters in UMC finishing include the magnetic flux density, the gap between the polishing tool head and the workpiece, the rotational speed of polishing tool head and so on. The technology experiment of UMC finishing for optical glass K9 is conducted, and the influence of main technological parameters on the material removal rate has been studied by analysis of experimental results. The analysis of removal profile curve of UMC finishing spots prove that the material removal function of UMC finishing meet the surface error convergence requiement in computer control precise optical surface machining. The part surfaces after UMC finishing are measured by an Atomic Force Microscopy (AFM), and the surface roughness Ra is 1.591 nm after polishing for 10 min. It is demonstrated that the polishing capability of the technology is excellent.
Theoretical and Experimental Research on the Material Removal Rate in Ultrasonic Aided Lapping of ZTA Ceramic
Authors: Jiao Feng , Zhao Bo
Published: September 2009

Lower machining efficiency of traditional lapping with free abrasive restricts the enhancement of the precision parts’ production efficiency. It is necessary to improve lapping efficiency on the premise of guarantee of lapping quality. In this paper, a new ultrasonic aided lapping technology was developed by combining lapping technology and ultrasonic machining technology and a series of lapping experiments of ZTA engineering ceramic with and without ultrasonic assistance were carried out. The results of theoretical analysis and experimental study show that it is the ultrasonic assistance of the lapping tool that promotes the enhancement of lapping efficiency and the ultrasonic aided lapping technique with fixed abrasive can be regarded as a high efficiency processing method of the precision engineering ceramic part.
Deep Hole Honing Based on Squeeze Film Damping Technology
Authors: Yu Tian Biao , Gong Ya Dong , Wang Wan Shan
Published: September 2009

In order to improve quality of deep hole machining, a new method of deep hole honing based on squeeze film damping technology is put forward. For analysis effect on damper parameters on honing quality, motion differential equation of honing spindle with a squeeze film damper (SFD) is established according to D' Alembert principle and according simulations are studied. Spindle of deep hole honing with a SFD is designed based on the result of simulations and experiments are carried on. Experimental result shows that SFD with reasonable design parameters has excellent damping function to honing spindle, and it can make the vibration of honing spindle reduced 20%～30% and the quality of deep hole machining improved 10%～20%.
Influence of Particle Effects on the Material Removal Rate Utilizing Electrokinetic Phenomenon
Authors: Leo C.S. , Blackburn T.L. , Butler David Lee , Ng Sum Huan , Yang C. , Danyluk Steven
Published: September 2009

With the demand for precise nanometric material removal with minimal defects, several non-contact ultraprecision machining techniques were developed over recent decades. The electrokinetic material removal technique [1] is one such method that allows material to be removed without any physical contact between the tool and the workpiece. In this work, the influence of the slurry mixture on the material removal rate for the electrokinetic material removal process is studied. During the process, it was observed experimentally that the mixture of the slurry affected the material removal rate. The parameters varied in the slurry mixture experiments were the size and concentration of the particles. Explanations for the behaviour of the material removal rate were also suggested during the study to further understand the electrokinetic material removal technique.
Finishing Characteristics in Barrel Finishing of Centrifugal Disc Type on Flow-Through System
Authors: Kitajima Koichi , Yamamoto Akihiro , Takahashi Shinji , Watanabe Masatomo
Published: September 2009

For the improvement of the performance in centrifugal disc finishing, the flow-through system for supplying the compound solution is tried and its influences on finishing characteristics are experimentally investigated. Workpieces (22 mm in diameter and 15 mm in thickness) of plain carbon steel (S45C in JIS), aluminum alloy (A2017) and copper alloy (C3604) are finished with ceramic media (Equilateral triangular prism 6 mm in side and 5 mm in thickness). The conclusions are summarized as follows; The compound solution has more influences on finishing characteristics than plain water. It makes the relative stock removal larger and the surface roughness smaller than the water. The relative stock removal and the media weight loss on the flow-through system are larger than those on the batch system.
Dynamic Friction Polishing Method Utilizing Resistance Heating for Efficient Removal of Electrically Conductive Diamond
Authors: Suzuki Kiyoshi , Iwai Manabu , Ninomiya Shinichi , Uematsu Tetsutaro
Published: September 2009

This paper proposes a new dynamic friction polishing method which utilizes resistance heating for solving a problem of too high pressure on a workpiece in the previous dynamic friction polishing method proposed by the authors. In the new method, an electrically conductive diamond workpiece (which has proper electric resistance) is heated by an electrical current flowing from a stainless steel disc tool to the diamond workpiece during the dynamic friction polishing and the polishing efficiency increases remarkably even at a very low pressure on the workpiece. For example, polishing efficiencies of 233 and 800 µm/min are attained at low pressures of 2 and 5 MPa, respectively, at a disc sliding speed of 2500 m/min.
The Detailed Performance of MCF Polishing Liquid in Nano-Precision Surface Treatment of Acrylic Resin
Authors: Wu Yong Bo , Sato Takashi , Lin Wei Min , Yamamoto K. , Shimada Kunio
Published: September 2009

This paper deals with the experimental investigation on the detailed performance of MCF (magnetic compound fluid) polishing liquid (MPL) in nano-precision surface treatment of acrylic resin that is essentially required for producing the model in the process of developing an inaugural mechanical system. The MPL is produced in practice by mixing iron powder, abrasive particle and -cellulose fiber into a MF (magnetic fluid), and hence a kind of functional fluid reacting to magnetic fields. Following the previous works confirming the performance of MPL in the surface finishing of acrylic resin, in this work a series of experiments were conducted to reveal how the process parameters affect the machining characteristics in details in order to establish the new technique. The results showed that a mirror surface can be easily obtained once the process parameters have been set up optimally.
A Study on Nozzle Wear Modeling in Abrasive Waterjet Cutting
Authors: Pi Vu Ngoc , Tuan Nguyen Quoc
Published: September 2009

This paper introduces a study on modeling of the wear of composite carbide nozzles in Abrasive Waterjet (AWJ) cutting. The model was built based on many long-term wear test data. In the model, the effects of jet-parameters such as water pressure, abrasive mass flow rate, orifice diameter, and initial nozzle diameter were taken into account. The model can be used for calculation the nozzle lifetime and therefore used for programming the AWJ cost optimization problem. Through the analyzing of the model, the effects of above parameters on the composite carbide nozzle wear were also more understood.
The Microchannel of Microfluidic Chip Fabrication by Micro-Powder Blasting
Authors: Huang Chiung Fang , Shen Yung Kang , Lin Yi , Wu Chi Wei
Published: September 2009

The process of micro-powder blasting is the high speed gas flow which mixed the micro-particle and gas to impact the brittle substrate by the specialized nozzle. This paper combined various diameters Al2O3 eroding particle with a novel masking technique to fabricate the pattern channels in soda glass with a width to 2000 μm and depth down to 1631 μm. The masking technology for fabricating microchannel is consisted by the combination of two polymers: 1) the elastic and thermal-curable poly-(dimethyl siloxane) (PDMS) for its erosion resistance and 2) the brittle epoxy resin SU-8 for its photosensitivity. This paper discusses the processing procedure by the different processing parameters (micro-powder impact pressure, the distance between nozzle and substrate, micro-powder size, and micro-powder impact time) to find the optimal process. The results show that the micro-powder size is the most important factor for the depth of microchannel of microfluidic chip. The surface roughness of microchannel of microfluidic chip is nearly 5-6μm.
Study on Micro Blasting of Glass for Micro Channel Forming
Authors: Koshimizu Shigeomi
Published: September 2009

The production of a compact chemical reactor called a micro channel device requires a glass microfabrication technique since it involves the formation of a micro channel on the surface of a glass substrate. We propose a direct mask drawing and micro blasting technique, designed to form a micro channel on a glass substrate. This method is suitable for producing a wide variety of patterns in small quantities. In conventional micro blasting the channel formed has a narrow base i.e. “V” shape cross-sections. Using a seesaw table to tilt the glass substrate during blasting, we can produce a wider based channel i.e. “U” shape cross-sections.
Nanoscratching-Induced Phase Tansformation of Monocrystalline Silicon – The Depth-of-Cut Effect
Authors: Mylvaganam Kausala , Zhang Liang Chi
Published: September 2009

This paper explores the effect of the depth-of-cut of an indenter on the phase transformations during nanoscratching on monocrystalline silicon on the Si(100) orientation. The analysis was carried out by molecular dynamics simulations. It was found that the depth-of-cut and the impingement direction of the indenter had a significant influence on the phase transformations in the initial impression region. At a relatively low depth-of-cut, only amorphous silicon was formed on the scratched surface. When the indenter impinged on a silicon surface with an angle, a bct5-Si crystalline phase in the initial impression region would emerge.
Analysis of Fixed Abrasive Pads with a Nano-Sized Diamond for Silicon Wafer Polishing
Authors: Shih Cheng Yi , Tso Pei Lum , Sung James C.
Published: September 2009

Current polishing pads cannot polish a workpiece without using slurry with free abrasive. The new slurry is required to be continually poured into the working area, so more than half of the slurry may be lost from the table without contacting the wafer surface; this leads to economic and environmental problems. In the current work, the fixed abrasive pad was used, where nano-sized diamond abrasives were embedded in the polishing pad; distilled water, rather than slurry, was used. The effect of various fixed abrasive pad designs on polishing characteristics during silicon wafer polishing was investigated. Moreover, the primary function of fixed abrasive was to remove the rough parts of silicon wafer as they were being polished. Consequently, it needed to disperse the nano-sized abrasives into the pad material with high hardness value; this way, working abrasives are not pressed into the pad material. Furthermore, with the use of a pad conditioner, the interior working abrasives were exposed to the pad surface. As a result, the best outcome of using the fixed abrasive pad with a nano-sized diamond was a surface roughness of Ra 0.47 nm.
Laser Micromachining of Silicon Substrates
Authors: Tangwarodomnukun Viboon , Wang Jun
Published: September 2009

Laser micromachining has been widely used for micro-component fabrication of various materials, such as silicon substrates where silicon wafer is ablated accurately and precisely through marking, scribing, drilling or dicing. Thermal damages can occur on the substrates when improper process parameters and methods are used. This paper presents a review on the micromachining of silicon substrates using conventional and novel lasers as well as water-assisted laser micromachining technologies. The basic concepts and approaches of the technologies are discussed along with the challenges to damage-free laser micromachining at commercially acceptable cutting rates.
Effects of Sodium Carbonate and Ceria Concentration on Chemo-Mechanical Grinding of Single Crystal Si Wafer
Authors: Takahashi H. , Tian Y.B. , Sasaki J. , Shimizu Jun , Zhou Li Bo , Tashiro Y. , Iwase Hisao , Kamiya Sumio
Published: September 2009

Chemo-mechanical grinding (CMG) process is a promising process for large-sized Si substrate fabrication at low cost. An encountered issue in current CMG process of Silicon (Si) wafers is metallic contaminations on ground Si wafer surface, which is attributed to the existence of sodium carbonate in wheel compounds. In this paper, four different CMG wheels were developed and grinding experiments were conducted to study the effects of exclusion of sodium carbonate and concentration of ceria abrasive on grinding performance. The grinding characteristics of the four wheels were analysized and discussed to reveal the effects of different compositions.
A Novel Single Step Thinning Process for Extremely Thin Si Wafers
Authors: Tian Y.B. , Zhou Li Bo , Shimizu Jun , Sato H. , Kang Ren Ke
Published: September 2009

The demand for extremely-thin Si wafers is expanding. Current manufacturing technologies are meeting great challenges with the continuous decrease in Si wafer thickness. In this study, a novel single step thinning process for extremely thin Si wafers was put forward by use of an integrated cup grinding wheel (ICGW) in which diamond segments and chemo-mechanical grinding (CMG) segments are alternately allocated along the wheel periphery. The basic machining principle and key technologies were introduced in detail. Grinding experiments were performed on 8-in. Si wafers with a developed ICGW to explore the minimal wafer thickness and grinding performance. The experimental results indicate that the proposed grinding process with the ICGW is an available thinning approach for extremely thin Si wafer down to 15μm
Blasting of Affected Layer of Silicon Surface Sliced by Wire EDM
Authors: Hidai Hirofumi , Sugita Taro , Tokura Hitoshi
Published: September 2009

Polycrystalline ingot slicing by wire electric discharge machining (W-EDM) has been investigated to reduce kerf loss and wafer thickness. In order to use the sliced wafers for semiconductor devices, the modified surface layer induced by W-EDM must be removed. In this paper, we have demonstrated the elimination of the layer by abrasive blasting. Three types of abrasives were blasted at a speed of 100 m/s. The surfaces blasted with WA #1000 and GC #1000 were smoother than that sliced with a wire saw. The modified layer induced by W-EDM slicing could be removed by blasting with WA #1000 while scanning the surface three times. Solar cells were fabricated using wafers with the blasted surface with an efficiency of 15.2%, which was almost the same as that of cells fabricated from the wire-sliced wafers.
An Approach for Improvement of Machining Accuracy in Micro End Milling
Authors: Shibahara Hideki , Kumagai Mikito , Kohda Seido , Okuda Koichi
Published: September 2009

In this study, an approach by the feed rate control was applied for the improvement of form accuracy in the micro end milling process. In this approach called adaptive control constraint, the feed rate is controlled so that the cutting load is constantly kept and the deflection of tool does not occur. However, this method is not always effective in the micro cutting process that the influence of size effect cannot ignore. Therefore, the relationship between the cutting conditions and the form error in the micro end milling is experimentally investigated. The experiments on the machining of metal mold steel with the micro end mill are carried out and the formulation as function of the cutting conditions and the form error is identified by means of regression analysis. The performance of the feed rate control was validated based on experimental results. As the result, it was confirmed that the form accuracy was improved.
Evaluation of GMR Head Durability against Nanoscale Scratches Using High-Field Transfer Curves
Authors: Tanaka Hideaki , Chiba Hiromu , Maeda Yukio
Published: September 2009

We investigated the durability of giant magnetoresistive (GMR) heads to nanoscale scratches created during the lapping process. Analysis using high-field transfer curves after deliberate scratching with an atomic force microscope (AFM) identified changes in the magnetization of the head and a reduction in pinning strength, which is a magnetic performance indicator. Additionally, finite element method (FEM) analysis suggested that the overall effects on the GMR head following nanoscale scratching increased with scratch depth.
Experimental Research of Grinding Force and Specific Grinding Energy of TC4 Titanium Alloy in High Speed Deep Grinding
Authors: Sheng Xiao Min , Tang Kun , Yu Jian Wu , Mi Hai Qing
Published: September 2009

Focusing on the characteristic of hard-to-grind for titanium alloy, experiments were conducted about grinding TC4 titanium alloy under high speed deep grinding (HSDG) condition. The changing of grinding force per unit area with maximum undeformed chip thickness hmax and equivalent cutting thickness aeq are analyzed in this paper. The effect of maximum undeformed chip thickness hmax and specific material removal rate Zw' on specific grinding energy es, material removal mechanism and consumption of grinding power in HSDG process are also discussed. The experiment results reveal that application of HSDG can improve machining efficiency of grinding TC4.
Analysis of Surface Temperature and Thermal Stress Field of Slab Continuous Casting
Authors: Zhang X.Z. , Jiang Zheng Yi , Tieu A. Kiet , Zhu Hong Tao , Tian Z.W.
Published: September 2009

There are many defects on the surface of continuous casting slab, such as corner cracks, longitudinal cracks etc. To analyze the cracks and determine their locations, two-dimensional heat transfer mathematical model and thermal elasto-plastic stress model of slab casting were established in this paper. The process of solidification, temperature field, and thermal stress distribution on slab surface were analyzed using finite element method. The effect of thermal stress on the cracks on the slab surface was discussed. The location of the cracks caused by thermal stress can be predicted. This is useful for finding approaches to overcome these defects.
Finite Element Simulation of Mix Driven by Electroosmotic Flow in Microchannels
Authors: Liu Ying , Ge Zhong Nian
Published: September 2009

Two-dimensional micro mix driven by electroosmotic flow was studied by finite element simulation and mixes speed of microchannels with unified zeta potential of the wall surface and the polar opposite one was contrasted. Relation between the section shape of the microchannels and the speed of mixing is cleared when the wall surface has the polar opposite zeta potential. The results show that section mixing speed of microchannel whose wall surface with unified zeta potential is lower than the one with polar opposite wall surface zeta potential. The ratio of width to height in microchannels of homolographic rectangle section and the height of microchannels with isosceles trapezoid section also have influence on mixing speed. When former increases or later decreases the mixing speed rapidly increases and then drops slowly. The mixing speed arrived at maximum value when the former and the later are 1.44 and 10μm, respectively.
Study on Parametric Influence, Optimization and Modeling in Micro WEDM of Ti Alloy
Authors: Vijayaraj R. , Gowri S. , Balan A.S.S.
Published: September 2009

Micro WEDM is a versatile technique used to machine electrically conductive materials to make components for micro system technologies. This paper presents an attempt to develop an appropriate machining strategy for micro WEDM of titanium alloy using zinc coated copper wire of 70 µm diameter. Voltage, capacitance, feed, wire tension and wire speed were taken as input parameters. Surface finish is considered as the measure of process performance. Design of experiments was done using Taguchi L16 orthogonal array and optimization was carried out using Taguchi S/N ratio technique. The results obtained from the experiments were analyzed with ANOVA method to find the significance of each input factor on the surface quality. In addition ANN model was developed and trained.
Research of Pulse Inversion Power Supply of ECM and its Techniques
Authors: Zhang Yong Jun , Tang Yong Jun , Guo Zhong Ning , Liu Xiao Kang , Li Feng
Published: September 2009

In order to improve machining accuracy and surface quality effectively in ECM (electrochemical machining), a novel pulse inversion power supply has been presented, which has following merits such as high-frequency short pulse, high-power, and compact size. The scheme of full bridge inversion has been selected in this power supply model, and feedback circuit realizes voltage adjusted automatically, and guarantees to stability of voltage. Protect circuit has designed to avoid the problem of workpiece-burn. Finally, a series of electrochemical mechanical polishing tests using the power supply have been carried out, and the results have proved that it helps to achieve well surface quality processed, and improve machining accuracy, and also verify feasibility of its scheme.
Effects of Combined Ultrasonic Vibration during the Sinking EDM Process for Cemented Carbide
Authors: Praneetpongrung Chaiya , Fukuzawa Yasushi , Nagasawa Shigeru
Published: September 2009

In recent years, to improve the electrical discharge machining properties, several trials have been applied with the ultrasonic vibration system which was combined on the sinking electrical discharge machine. In this paper, the effects of the ultrasonic vibration were investigated with the designed sinking EDM machine. Some experimental parameters of tool electrode polarity, rotational workpiece speed and directions were examined during the sinking EDM process on the cemented carbide material of G5. Material removal rate, electrode wear ratio and surface roughness were estimated as the machining properties under finishing machining conditions. The experiments were carried out on ultrasonic longitudinal frequency 59 kHz and electrode spindle till 1,000 rpm. Two rotational apparatuses were used simultaneously on the opposite rotational direction during discharge machining. The discharge conditions were estimated with the waveforms analysis. As the results, the EDM device system which was combined ultrasonic vibration, improved the material removal rate and surface roughness of the EDMed workpiece.
Remote Fault Diagnosis System of Ultrahigh Speed Grinding Based on Multi-Agent
Authors: Wang Wan Shan , Yu Tian Biao
Published: September 2009

A remote fault diagnosis method for ultrahigh speeding grinding based on multi-agent is presented. The general faults of ultrahigh speed grinding are analyzed and diagnosis model based on multi-agent is established, the dialogue layer, problem decomposition layer, control layer and problem solving layer in the process of diagnosis are studied and the knowledge reasoning model of fault diagnosis is set up based case-based reasoning (CBR) combining rule-based reasoning (RBR). Based on theoretical research, a remote fault diagnosis system of ultrahigh speed grinding is developed. Results of the system running prove the theory is correctness and the technology is feasibility.
Development of New PCD Made Up of Boron Doped Diamond Particles and its Machinability by EDM
Authors: Suzuki Kiyoshi , Shiraishi Yoichi , Nakajima Nobuhiro , Iwai Manabu , Ninomiya Shinichi , Tanaka Yukinori , Uematsu Tetsutaro
Published: September 2009

This paper deals with a new PCD named EC-PCD which is made up of boron doped diamond particles and its properties related to EDM machinability. For the purpose of improving various properties of standard PCD including resistance to heat, wear and reactivity, a new PCD (EC-PCD) was manufactured on a trial basis using electrically conductive diamond particle as a basic ingredient. Grain size, resistivity and thermal conductivity of the boron doped diamond used are 10μm, 5~37×10Ω•m and 440~580W/m•K. In this report, machinability of newly developed PCD (EC-PCD) by wire EDM was investigated in comparison with that of standard PCD. In wire cutting of 2 types of PCD in water under the condition of open gap voltage: ue=80V, set peak current: iP=0.8A and pulse condition: te/to=20/20μs, it was found that roughness of the first cut surface of standard PCD was approximately 8μm Rz, while that of EC-PCD was far better such as 3μm. Also in finish cut (7th cut), the latter achieved the value of Rz=1.7μm while the former achieved only the value of Rz=2.7μm. Expecting better performance, EC-PCD was tested also in oil. As a result, the best achieved roughness was improved to Rz=0.4μm with no chipping on the edge. To explore a reason for such a good roughness obtained, the cut samples were observed on the SEM, which revealed that the diamond particles in EC-PCD were flattened by electro discharge.
Micro-Raman Stress Investigation of Polycrystalline Diamond Compact (PDC)
Authors: Xu Guo Ping , Xu Gen , Yin Zhi Min , Jiang Rong Chao
Published: September 2009

The residual stresses on the top surface and side face of the diamond layer of PDC with 25.4mm in diameter and 3.2mm in thickness were measured using Micro-Raman Spectroscopy, thus the stresses and their radial and vertical distributions were obtained. To evaluate the magnitude of the thermal residual microstress in the diamond layer of PDC, the tungsten carbide substrate of PDC was cut by electric discharge machining (EDM), and several Raman measurements were performed on the top surface of the diamond layer. The results show that 1) the stresses in the central part of the diamond surface are compressive, the biggest stress is about 600 MPa, the magnitude of the stress decreases from the center to the edge of PDC, and at about 2mm near the edge of PDC, the stress becomes tensile; 2) the stresses on the side face of the diamond layer are tensile, the maximum is about 580 MPa near the interface. These tensile stresses are thought to be one of the main factors to cause delamination of PDC used for cutting tools; 3) the measured value of the microstress in the diamond layer is 62.5MPa.
Control of the Behavior of Abrasive Grains by the Effect of Electrorheological Fluid Assistance - Study on Electrorheological Fluid-Assisted Micro Ultrasonic Machining -
Authors: Tateishi T. , Shimada K. , Yoshihara Nobuhito , Yan Ji Wang , Kuriyagawa Tsunemoto
Published: September 2009

. Micro ultrasonic machining (micro-USM) is an effective machining method for hard brittle materials. In the micro-USM process, the workpiece materials are machined through the accumulation of small brittle fractures generated by the impacts of abrasive grains. Therefore, it becomes difficult to obtain a smooth machined surface. In the proposed electrorheological fluid-assisted ultrasonic machining (ER fluid-assisted USM), the behavior of abrasive grains is controlled using the effect of dielectrophoretic force acting on the abrasive grains and the ER effect. The behavior of the abrasive grains can be controlled by changing the electric field distribution. In the present paper, the shape and position of the auxiliary electrode are arranged in order to control the abrasive grains to the side surface of the micro rectangular tool. By positioning the auxiliary electrode parallel to the micro rectangular tool, it becomes possible to concentrate abrasive grains to the side surface of the micro rectangular tool. Smoothing of the side surface of the workpiece by using the side surface of the micro rectangular tool is then investigated. As a result, the surface roughness of the side surface of the workpiece can be improved.
The Effects of Shear Stress on the Lubrication Performances of Oil Film of Large-Scale Mill Bearing
Authors: Wang Jian Mei , Huang Qing Xue , Jiang Zheng Yi , Tieu Kiet
Published: September 2009

A new coupling numerical algorithm has been developed to integrate Finite Difference Method (FDM) with Boundary Element Method (BEM) to analyze shear performance of oil film by iteratively solving a series of equations such as the film flow velocity and shear stress equations for contact bodies in bearing system. With consideration of the variations of viscosity and density with pressure and temperature, the effects of shear stress of oil film layers on lubrication performance of contact surfaces under different loadcases were discussed. Moreover, Germany-made Anton Paar MRD (Magnetic Rheologic Device) was used to determine the relationship between the viscosity and shear stress of lubricating oil. The conclusions were verified to be beneficial to the further study on lubricating performance of heavy contact components and to prolong their service lives.
Research on the Heat Partition Ratios in Grinding Area
Authors: Yuan Suo Xian , Hu Ming , Cai Guang Qi
Published: September 2009

Grinding temperature is the main factor to limit the improvement of grinding efficiency. The main reason of grinding temperature rise is amount of heat transfer into the workpiece in grinding process. How to determine the proportion ratio, which heat transfers into the workpiece, is the main research issue to the precise machining scholars. In this paper, the heat resistance model is used to analyze the proportional coefficient about how much heat transfer into the grinding wheel, and the factors which to influence this coefficient are discussed. The moving heat source method is used to calculate the temperature field caused by single grain heat source, and the heat integral method is used to calculate the heat contains by the grinding chip, and then the heat proportional coefficients transferring into the chip and workpiece are determined respectively.
ELID Assisted Grinding of Optical Glass with Fine and Coarse Grained Copper-Resin Bonded Diamond Wheels
Authors: Zhao Qing Liang , Chen Jun Yun , Yao Jun
Published: September 2009

In this paper, a copper-resin bonded diamond wheel was applied to machine the optical glass on a precision grinder. The process of truing and pre-dressing with ELID (electrolytic in-process dressing) were first carried out for the grinding wheels, then the ELID assisted grinding experiments were conducted with the special fine and coarse grained diamond wheels. The experimental results show that the fine and coarse grained wheels can all generated the smooth surface with the surface roughness in nanometer scale and the coarse grained diamond wheel correlates to the slightly more surface damage than the fine grained diamond wheel, which also proves that the high efficient grinding of the optical glass with a good surface quality can be realized with the coarse grained copper-resin wheel on a precision grinder and the grinding wheels were all well conditioned with the conditioning method presented in this paper.
Molecular Dynamics Simulation of Chemo-Mechanical Grinding (CMG) by Controlling Interatomic Potential Parameters to Imitate Chemical Reaction
Authors: Shimizu Jun , Zhou Li Bo , Yamamoto Takeyuki
Published: September 2009

This paper reports a molecular dynamics simulation of chemo-mechanical grinding (CMG) of silicon wafer by controlling the interatomic potential parameters to imitate the chemo-mechanical or mechano-chemical reactions between an abrasive grain and a Si wafer. Some comparisons between diamond grinding and CMG were made by using the proposed simulation model. From the simulation results, reductions of surface damages, wears of abrasive grain and scratching forces in CMG were confirmed to be same as observed in actual experiments by a CeO2 abrasive wheel, and the availability of proposed simulation model was verified.
Improvement of Grindactivity by Dressless Wheel Treatment in Dry Grinding of Carbon
Authors: Ohashi Kazuhito , Sumimoto Y. , Fujita Y. , Tsukamoto Shinya
Published: September 2009

The grindactivity of wheel is remarkably lost by the loading of wheel surface in dry grinding of hard carbon parts. In this report, we propose the dressless wheel treatment, in which loading chips are removed with adhesive tape, and experimentally investigate its effect on recovery of grindactivity, analyzing the stock removal, the grinding current and the surface roughness in repeat of grinding cycle with treated and non-treated wheels. The removal and finishing performances of loaded wheel are recovered by the dressless wheel treatment.
Influences of Aging Precipitation on Corrosion Resistance of 18Cr-18Mn-2Mo-0.77N HNS
Authors: Zhang Zu Rui , Li Hua Bing , Jiang Zhou Hua , Li Zhen , Xu Bao Yu
Published: September 2009

Influences of aging precipitation of Cr2N and Chi (χ) phases on the resistance to pitting corrosion and intergranular corrosion of 18Cr-18Mn-2Mo-0.77N high nitrogen steel (HNS) as a type of fundamental and structural materials were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) pattern and electrochemical methods. Intergranular, cellular Cr2N and χ phases precipitate gradually along grain boundaries and inward grains. The volume fraction of precipitation presents a C-curve with a nose temperature of 850°C during 2h aging treatment. The solution-treated (ST) HNS exhibits the highest pitting corrosion potential because of high nitrogen content in steel, and especially no precipitation. The pitting corrosion resistance of aged HNS decreases because of the formation of aging precipitation which results in the depletion of Cr and Mo in the matrix. The pitting corrosion potentials firstly decrease then increase as the same tendency as the amount of precipitation expect 850°C and 900°C. Double loop electrochemical potentiokinetic reaction (DL-EPR) results show that the change tendency of IGC susceptibility is well consistent with the amount of precipitation of aged HNS for 2h at various temperatures. With prolonging the aging time at 850°C, aged HNS presents more obviously intergranular sensitization due to the formation of aging precipitation which results in the depletion of Cr and Mo.
Studies on Crack Propagation of Carbon Fiber Reinforced Epoxy Resin Composite
Authors: Yu Jia , Liu Yi Zhuo , Shi Rong Rong
Published: September 2009

Unidirectional carbon fibre reinforced resin matrix composite (CFRP) with different fibre volume fraction are stretched dynamically under static load in SEM, initiation and propagation mechanism of crack is in-situ observed, and tensile fracture of specimens is also observed. The results show that: Microscopic cracks are mainly originated from fracture of fibre, numerous fibre cracks transfixion each other in form of matrix or interface cracking, and cause failure of CFRP. Microscopic crack propagation path is related to the thickness of matrix layer between fibres. Propagation of single fibre crack at interface accord with description of microscopic crack deflection criterion for fibre reinforced composite, but the crack deflection criterion cannot descript microscopic crack propagation mechanism of unidirectional CFRP effectively, because distribution discreteness of fibre and its strength are not considered.
Acridine as Effective Corrosion Inhibitor for Hot Dipped Coatings on Steels in Diluted HCl Solution
Authors: Ju Hong , Peng Tian Shu , Li Yan
Published: September 2009

The environmental and health hazards associated with chromium-containing solution have aroused wide public concern, so attempts have been made to find alternatives for metal finishing. In the present paper, inhibition effect of acridine on corrosion of hot dipped Zn and Zn-Al alloy coatings on steels in diluted hydrochloric acid was investigated using weight loss test, electrochemical measurement, and quantum chemistry analysis. The results showed that inhibition efficiency increased with inhibitor concentration, and the highest inhibition efficiency was up to 99%. And acridine adsorbed on coating surface by chemisorption. Quantum chemistry calculation results indicated that acridine possesses planar structure with a number of active centers, and showed a good ability of electron exchange with the coating surface.
Influence of In Situ MgO Coating on Corrosion Resistance of Pure Magnesium in Normal Saline
Authors: Zhao Li Chen , Cui Chun Xiang , Liu Shuang Jin , Qi Yu Min
Published: September 2009

Magnesium and its alloys are potential biodegradable materials due to their outstanding biological performance, but their poor corrosion resistance greatly limits their applications as bone implants. This paper investigates the influence of in situ magnesium oxide coating on corrosion resistance of pure magnesium in normal saline. It was discovered by SEM that rough and porous oxide coatings were obtained on the surface of the pure magnesium after heat-treated at 400~500°C and the samples were severely corroded after immersion in 0.9 wt.% NaCl solution for 3 days. It also showed that the weight loss rates of the treated pure magnesium (TPM) samples were about 5~6 times higher than that of the untreated pure magnesium (UPM) sample. Electrochemical measurements showed that the corrosion current density (icorr) of the TPM samples was one order of magnitude higher than that of the UPM sample.
Effect of Boron on Magnetic Properties and Corrosion Resistance of High Energy Magnets
Authors: Yu L.Q. , Zhang Y.P. , Fu Q.T.
Published: September 2009

Element boron played an important role on magnetic properties and corrosion resistance of high energy density NdFeB products. The magnets were prepared by traditional powder metallurgy technique. It was found that with addition of 5.53 % B there was easy-plane phase formed. It owned not only lower remanence Br and coercivity iHc, but also poor corrosion resistance of magnet. As B content increase, the magnetic properties improved greatly, and obtained better properties at a content 5.7-5.87 % B. As increased B content further, superabundance B element formed too much B rich phase and led to Br decrease. Volume percent of phases calculated by theory formula, with the consumption of 0.1 % Nd oxided, it can be found that as B content increased from 5.53 %, the volume of main phase increased and easy-plane type Nd2Fe17 phase decreased in magnet, which resulted in Br, iHc increase. As B content increased higher than 5.82 %, more B rich phases formed which well isolated main phase grains and resulted in iHc increase. But too much B rich phase would decrease main phase proportion and lead to Br decrease. Examination of microstructure of magnets showed as B content increased from 5.53 % to 6.16 %, average matrix grain size was enlarged from 6.5µm to 8.2µm, and the proportion of sharp shape grains relatively increased as well. Abnormal grain growth was easily happened at higher B content. In addition, the decreased squareness Hk/iHc of magnets at higher B content also suggested inconsistent distribution of grain size and shape. Corrosion current density measured by polarization test for magnet with addition of 5.76 % B, near stoichiometric composition of Nd2Fe14B, owned lowest value and best corrosion resistance. Formation of Nd2Fe17 phase (lower B content) or B rich phase (higher B content) was not benefit for corrosion resistance improvement.
Hydrogen Permeation Characterization of Hot-Dip Galvanized Steel in Simulated Marine Atmospheric Environment
Authors: Zhang Da Lei , Li Yan
Published: September 2009

Hydrogen permeation current curve of galvanized steel with hot-dip zinc coating exposed to simulated marine atmosphere was measured using a modified Devanathan-Stachurski cell. Effect of temperature, humidity and coating defect on its hydrogen permeation behaviour was also investigated. The results indicated that hydrogen permeation current density and the amount of hydrogen accumulated increased evidently with temperature and humidity rising at moist environment; meanwhile, hydrogen absorption when coating defect occurred was accelerated by the cathodic protection of the exposed steel surface afforded by surrounding zinc coating.
Corrosion Protection of a SiCp/ZL101 Composites by Using Plasma Electrolytic Oxidation Method
Authors: Cui Shi Hai , Tang Hong Tao , Li Jian Yu , Han Jian Min
Published: September 2009

A dense ceramic coatings with a thickness of 95μm was fabricated on a SiCp/ZL101 aluminum composites by using a plasma electrolytic oxidation(PEO) method. The XRD analysis showed that the PEO coating was mainly composed of α-Al2O3 γ-Al2O3 and mullite.The corrosion resistance of the PEO coatings and SiCp/ZL101 aluminum composites was estimated by the immersion test, salt spray test and electrochemical test. All the test results showed that the corrosion resistance of the composite was improved by the existence of the ceramic coating.
Corrosion Resistance of Rare Earth Modified Chromizing Coating on P110 Oil Casing Tube Steel by Pack Cementation
Authors: Lin Nai Ming , Xie Fa Qin , Zhong Tao , Wu Xiang Qing , Tian Wei
Published: September 2009

The rare earth (RE) modified chromizing coating was obtained on P110 oil casing tube steel (P110 steel) substrate by means of pack cementation technique to enhance the resistance against corrosion of P110 steel. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) were employed to research microstructure, composition distribution and phase constitution of the chromizing coating. The effect of minor addition of RE on the microstructure of chromizing was discussed. Corrosion resistance of chromizing coating was investigated and compared with that of bare P110 steel via electrochemical corrosion and immersion corrosion in simulated oilfield brine solution, respectively. The results showed that a uniform, continuous and compact coating was formed on P110 steel. The coating with RE addition was more compact than that of the coating added no RE, and a small amount of RE addition could promote the chromizing procedure notably. From SEM and EDX investigation, it had been confirmed that the coating was composed of two different layers, an out layer and an inner layer; the coating mainly contains Fe and Cr; the concentration of Cr decreased as the distance from the surface increased, yet Fe presented the inverse trend. XRD analysis indicated the coating was built up by (Cr, Fe)23C6 referring to the out layer, (Cr, Fe)7C3, Cr7C3 and α-(Cr, Fe) corresponding to the inner layer. Electrochemical corrosion consequence was obtained as follows: the self-corroding electric potential of chromizing coating was higher, and the corrosion current density was lower than that of bare P110 steel, which revealed that chromizing coating had better anti-corrosion performance; immersion corrosion results demonstrated the mass loss of chromized P110 steel was lower, and this meant that chromizing coating had a better corrosion resistance than that of bare P110 steel on the experimental condition. A compact (Cr, Fe)xCy coating can be fabricated by pack cementation technique. As a result of minor RE addition, microstructure and corrosion resistance of the chromizing coating are improved obviously.
Effect of Catalytic Crystalline Waterproof Coatings on Steel Reinforcement Corrosion of Concrete
Authors: Gao Li Xiong , Kong Li Juan , Chen Hui
Published: September 2009

Catalytic crystalline waterproof coatings (CCWC) can penetrate into pores and cracks of concrete and catalyze reaction to increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate the effect of CCWC on corrosion of concrete. The test results of water impermeability, chloride permeability and potential clearly showed that CCWC could stop water and any soluble salts from penetrating the concrete to cause corrosion. Moreover, results of the secondary impermeability test and SEM micrographs indicated that the active compound could work for a longer term and endow the cement-based materials with self-healing function, which make concrete more compacted. Therefore, it was concluded that CCWC is very effective to protect the steel from corrosion in concrete.
Erosion Resistance of TiC/Fe Composite at High Temperatures
Authors: Li Bin , Liu Zong De , Chen Yong , Zhao Li Ping
Published: September 2009

With an aim to investigate erosion properties, TiC/Fe composites fabricated by self -propagating high-temperature synthesis and pseudo heat isostatic pressing (SHS/PHIP) technique were studied experimentally. Phase composition, microstructure, composition and microhardness of the products are analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and microhardness tester, respectively. The elevated temperature erosion tests of the TiC/Fe composites were tested with the help of a GW/CS-MS type tester using SiO2 quartz and Al2O3 corundum as the abrasive. The influences of the different parameters such as impact angle, environment temperature, abrasive, on the erosion property of the TiC/Fe composites were studied. The morphology of the worn surface was analyzed with SEM to determine the erosion mechanisms.
Finite Element Simulation of Lamb Wave with Piezoelectric Transducers for Composite Plate Damage Detection
Authors: Qu Wen Zhong , Xiao Li
Published: September 2009

Structural health monitoring (SHM) is an emerging research area with multiple applications. Lamb waves are ultrasonic elastic waves that travel inside and along thin plates and is frequently used as diagnostic tools to detect damage in plate-like structures. In this paper, a transient dynamic finite element simulation of Lamb wave with piezoelectric transducers for damage detection in a composite plate is carried out. The embedded cross-shaped piezoelectric active sensor arrays were used to generate and receive guided Lamb waves propagating in the plate structure. A full-scale FEM model for the laminate was created using three-dimensional eight-node layered structural solid element and piezoelectric active sensors were created using coupled field elements on the commercial finite element code ANSYS platform. The beam forming technique of Lamb waves is used to locate damage in the plate .The results of the numerical simulation demonstrate the effectiveness of the approach.
The Doping of Ag+ Enhanced the Antibiocorrosive Effect of Titania in Seawater under Visible Light
Authors: Hong Hai Xia , Yin Yan Sheng , Wang Hong Feng , Chen Shou Gang , Liu Tao , Zhao Li Li
Published: September 2009

Sol-gel TiO2 thin films undoped and doped with Ag-ions have been formed on 304ss by dip-coating method respectively. The Ag/TiO2 films are compact and have anatase phase with stable crystal structure and have a thickness of 50 nm approximately. The bactericidal rate of the Ag/TiO2 film against sulfate-reducing bacteria (SRB) strains reaches 97.1% when doping Ag+ with a percentage of 3%. The analysis of potentiodynamic polarization curves illustrates Ag/TiO2 film decreases the corrosion rate obviously.