MECHANICS OF ENAMEL ADHERENCE, I

The customary method for preparation of metallographic specimens is described, with modifications necessary to adapt the method to preparation of sections of enameled metal. The modifications noted are (1) cutting the section at an angle to the plane of the sheet so as to expose a wider band of enamel and metal, (2) maintaining the direction of grinding and polishing so that the action is from enamel to metal portions of the surface a t all times, and (3) using a paraffin covered wheel with levigated alumina as a polishing medium, in order to secure a flat surface. The use of the metallographic microscope in the examination of these specimens is described with some conclusions regarding the false appearances of lincs of contact, etc., due to improperly prepared specimens.     

抛光机磨头微观冲击机理与实验

为了研究磨头微观加工机理,提出低、高速磨头微观冲击机理。建立微观冲击速度和振幅模型。通过SEM实验得出瓷砖微观缺陷形成过程,并验证了冲击机理理论符合瓷砖表面形貌。通过振动实验得出:粗抛阶段,低速磨头可以减少瓷砖缺陷,降低冲击振动;精抛阶段,高转速磨头可以提高瓷砖的表面质量。     

磨粒的“后部效应”对瓷砖破碎及振动的影响

为了研究磨头微观加工机理,提出低、高速磨头微观冲击机理。建立微观冲击速度和振幅模型。通过SEM实验得出瓷砖微观缺陷形成过程,并验证了冲击机理理论符合瓷砖表面形貌。通过振动实验得出:粗抛阶段,低速磨头可以减少瓷砖缺陷,降低冲击振动;精抛阶段,高转速磨头可以提高瓷砖的表面质量。     

Preparation of Thin Sections of Coated Fibers for Characterization by Transmission Electron Microscopy

A method of preparing transmission electron microscopy (TEM) specimens of coated ceramic fibers has been developed, which produces large electron transparent areas due to the minimal preferential milling of the fiber, coating, or epoxy matrix. Multiple individual fibers or tows are impregnated with a high-temperature epoxy and contained to assure a high fiber-to-epoxy volume ratio. The samples are then sectioned and mechanically thinned either parallel or normal to the fiber axes using a wedge polisher on diamond lapping films to achieve a thickness of less than 5 μ.m. The thinned sample is then ion-milled to electron transparency in less than 30 min, giving representative specimens of the coating, fiber, and coating-fiber interface. This technique is also well suited to preparing extremely flat specimens for scanning electron microscopy analysis of thin coatings. Examples of TEM sections of coated fibers prepared using this technique are presented.     

在MQ1350A磨床上磨削高精度抛光辊

通过选用合理的砂轮、磨削工艺参数、磨削液等并进行适当的修整砂轮、调整与平衡磨床,即可在MQ1350A普通外圆磨床上磨削修复进口1450冷轧机抛光辊。经分析磨削结果可知,在MQ1350A普通外圆磨床上磨削高精度要求的进口1450冷轧机抛光辊是完全可行的。     

Evaluation research of polishing methods for large area diamond films produced by chemical vapor deposition

The current study compared several polishing techniques of chemical vapor deposition (CVD) diamond films. Although research on various diamond polishing techniques has been carried for years, some issues still need to be examined in order to facilitate application on large areas in a cost-efficient manner. In the present work, microwave plasma enhanced chemical vapor deposition (CVD) was used to obtain diamond films with full width half magnitude (FWHM) less than 10 wavenumbers at 1332 cm^− 1 Raman peak. The diamond films were processed through mechanical polishing, chemical-assisted mechanical polishing, thermo-chemical polishing, excimer laser ablation, and catalytic reaction assisted grinding. A profilometer, an atomic force microscope, and a scanning electron microscope have been used to evaluate the surface morphology of diamond films before and after polishing. The results obtained by using the above mentioned techniques were analyzed and compared.     

陶瓷材料加工表面完整性及其对材料可靠性的影响

采用磨削-抛光加工、金刚石锯片切割加工、超声波加工和电火花线切割加工技术对Al2O3/TiC陶瓷材料进行加工.研究了各加工方法对陶瓷材料的加工表面完整性及其可靠性的影响.结果表明:加工方法对陶瓷材料加工表面完整性和可靠性有很大的影响.磨削-抛光加工的陶瓷试样表面粗糙度小,硬度高,抗弯强度及其可靠性最高.金刚石锯片切割加工和超声波加工次之;电火花加工陶瓷试样表面粗糙大,硬度低,抗弯强度及其可靠性最低.电火花加工陶瓷表面产生一硬度低且表面粗糙的约8μm厚的热影响层,加工表面含有大量的电火花腐蚀凹坑,随电流的增大,电火花加工陶瓷试样的抗弯强度及其可靠性降低.超声波加工陶瓷试样的表面完整性与磨料粒度有关,随磨料粒度的减小,陶瓷试样的抗弯强度及其可靠性增加.     

Influence of Co-Doping on the Sintering Path and on the Optical Properties of a Submicronic Alumina Material

Sintering in air was performed on pure and CaO/TiO₂ co-doped slip cast α-alumina samples. The relative density/grain size relationship, referred to as sintering path, has been obtained for each composition. Fully dense samples were obtained after an additional hot isostatic pressing (HIP) step on the pure and doped materials. After grinding and polishing, the optical properties were measured on flat windows (thickness around 1 mm) in the ultraviolet, visible, close-infrared, and mid-infrared ranges. The influence of a tiny residual porosity on the optical properties, impossible to quantify using standard methods, has been investigated.     

Grinding and polishing efficiency of a novel self-glazed zirconia versus the conventional dry-pressed and sintered zirconia ceramics

ABSTRACT

The grinding and polishing efficiency of self-glazed zirconia and Zenostar zirconia, prepared by wet and dry approaches, respectively, were evaluated. Each sample was divided into two subgroups (n?=?5). One was ground, and the other was polished by following the clinical adjustment protocol. Statistics were analysed by independent t-test to a significance level of p?<?.05. More material was ground off in self-glazed zirconia than in Zenostar zirconia (p?<?.05) during the same period, especially during the coarse grinding procedure (p?<?.05), whereas the grinding efficiency in fine grinding stage was not significantly different (p?>?.05). The polishing efficiency of the whole and of the fine polishing procedure of the two kinds of zirconia was significantly different (p?<?.05). It thus can be concluded that grinding and polishing efficiency of a novel self-glazed zirconia is significantly higher than that of the conventional Zenostar zirconia.     

超精密表面研抛磨粒的研究进展

半导体材料的超精密加工是一种获得高表面质量和表面完整性的加工技术,研抛磨粒是实现半导体材料超精密加工的关键耗材之一。从研抛磨粒的组成方式和结构特点,概述了研抛磨粒的研究现状和发展趋势。首先,构建了研抛界面内半导体材料工件-研抛磨粒-研抛垫的接触模型,讨论了研抛磨粒的材质、形状、浓度、粒径等因素对半导体材料研抛质量和研抛效率的影响;其次,从材质和粒径等方面介绍了混合磨粒的研抛性能,以及相应的研抛机理;然后,从材料结构和化学作用等角度总结了复合磨粒在超精密加工技术中的应用;最后,展望了研抛磨粒未来的研究方向。     

电解铜箔生产用新型阴极辊在线抛磨装置的设计

介绍了一种基于花键副传动的铜箔沉积用阴极辊在线抛磨装置,解决了传统装置中抛磨轮摆动惯量大,振动难以控制的问题,实现了抛磨轮的精确控制,有效消除了离线研磨中产生的纵向浅沟状刮削痕,提高了阴极辊辊面光洁度和一致性,使得生产的铜箔具有良好的各向同性性能。     

Constitutive Law for the Densification of Fused Silica, with Applications in Polishing and Microgrinding

We discuss a constitutive model describing the permanent densification of fused silica under large applied pressures and shear stresses. The constitutive law is assumed to be rate-independent and uses a yield function coupling hydrostatic pressure and shear stress, a flow rule describing the evolution of permanent strains after initial densification, and a hardening rule describing the dependence of the incremental densification on the levels of applied stresses. Normality, or lack thereof, of the permanent strain increments to the current yield surface in stress space allows for various relative contributions of densification and shear flow in the ensuing deformation. The constitutive law accounts for multiaxial states of stress, since during polishing and grinding operations complex stress states, with large shear components due to friction and abrasion, occur in a thin surface layer due to the action of abrasive particles. We apply the constitutive law in estimating the extent of the densified layer during the mechanical interaction of an abrasive grain and a flat surface under polishing and grinding conditions. The grain is assumed to be spherical and in Hertz contact with the surface, or sharp and in point contact. The effect on the densified depth of stress relaxation due to densification is discussed.     

Metal surface characteristics dictate bacterial adhesion capacity

Bacterial adhesion can be dictated by different surface characteristics. In this study we concentrate on the surface roughness of a stainless steel material. We prepared the stainless steel surfaces by 3D polishing, brushing, grinding and electropolishing. Untreated stainless steel surfaces were also considered. The corresponding surface roughness was assessed by profilometry and atomic force microscopy. In experiments we have used different types of bacteria. The rate of adhered bacteria on metal surfaces was determined spectrophotometrically. The results showed that the rate of adhered bacteria increases with increasing surface roughness. Scanning electron microscopy was used to image surfaces in order to determine locations of adhered bacteria. The increased adhesion of bacteria on more rough surfaces results from an increased interplay between the increasing effective surface area and increasing numbers of cracks, voids and gaps.     

Influences of liquid elastomer additive on the behavior of short glass fiber reinforced epoxy

In this study, improvements in mechanical and thermal behavior of short glass fiber (GF) reinforced diglycidyl ether of bisphenol-A (DGEBA) based epoxy with hydroxyl terminated polybutadiene (HTPB) modification have been studied. A silane coupling agent (SCA) with a rubber reactive group was also used to improve the interfacial adhesion between glass fibers and an epoxy matrix. 10, 20, and 30 wt% GF reinforced composite specimens were prepared with and without silane coupling agent treatment of fibers and also HTPB modification of epoxy mixture. In the ruber modified specimens, hardener and HTPB were premixed and left at room temperature for 1 hr before epoxy addition. In order to observe the effects of short glass fiber reinforcement of epoxy matrix, silane treatment of fiber surfaces, and also rubber modification of epoxy on the mechanical behavior of specimens, tension and impact tests were performed. The fracture surfaces and thermal behavior of all specimens were examined by scanning electron microscope (SEM), and dynamic mechanical analysis (DMA), respectively. It can be concluded that increasing the short GF content increased the tensile and impact strengths of the specimens. Moreover, the surface treatment of GFs with SCA and HTPB modification of epoxy improved the mechanical properties because of the strong interaction between fibers, epoxy, and rubber. SEM studies showed that use of SCA improved interfacial bonding between the glass fibers and the epoxy matrix. Moreover, it was found that HTPB domains having relatively round shapes formed in the matrix. These rubber domains led to improved strength and toughness, due mainly to the “rubber toughening” effect in the brittle epoxy matrix.     

基于Matlab陶瓷墙地砖抛光运动模拟分析

优质的墙地砖磨削效果要求墙地砖表面各点处的磨削频数尽可能地一致,才会产生满意的磨削加工效果。但在实际抛光中,磨削容易产生暗带。本文以PGJ瓷质砖精密抛光机为例,描述了该抛光机的运动过程,并建立抛光运动的数学模型和仿真模型,用Matlab软件对抛光运动进行仿真分析,在仿真模型中可方便修改运动参数,以比较抛光效果,对抛光运动参数的确定和抛光质量的研究有参考作用。     

Role of microstructure in the grinding and polishing of α-sialon ceramics

The grinding and polishing behaviour of three tailored α-sialon microstructures made of the same chemical composition: fine-grained, bimodal and large elongated-grained, were determined. The fine-grained microstructure was characterised by extensive lateral cracks in the grinding process and widespread grain pullout during the mechanical polishing; in contrast, the large elongated-grained microstructure exhibited high grinding damage resistance, and a defect-free, mirror-like surface after mechanical polishing. The bimodal microstructure showed an intermediate behaviour during both processes. The material removal mechanisms during grinding and polishing were analysed and modelled as a function of grain size and aspect ratio.     

大规格陶瓷砖抛光过程仿真与试验研究

基于Preston方程,分析了磨削速度、磨削时间与磨削量的函数关系。在大平面机械抛光的运动学分析基础上,综合磨削速度、磨削时间共同影响,建立平面抛光均匀性分析模型,应用matlab软件进行了仿真。仿真与试验研究表明模型正确可靠,为进一步研究运动参数对抛光质量的影响规律奠定了良好基础。     

沥青中间相的光反射显微分析方法优化

对沥青样品采用冷镶嵌树脂成型,用自动磨抛机配不同粒级防水砂纸对成型样品多次研磨、抛光;将待测样品在反射式偏光显微镜下观察、测量,采用面积百分比法测得中间相含量。可避免计数法中间相粒径的影响,分别测量不同粒级中间相的比例。     

新型不等距抛光机磨头创新设计及动力学分析

为了研究大规格瓷砖加工设备,提出一种新型不等距抛光机磨头。从结构原理上进行了创新设计,并继承了摆动式抛光磨头的优势,弥补了存在的缺陷。以新型不等距抛光磨头为研究对象,建立磨块距方程和磨头动力学模型。得出不等距磨块的分布规律改变了各个磨块切出磨削状态的隔间时间,同时分析得出不等距磨头垂直方向的磨削力平稳,振动减小。     

Surface Analysis of a Treated Soda-Lime Glass

The physicochemical properties of the surface of a soda-lime glass were characterized with X-ray photoelectron spectroscopy and transmission electron microscopy. A variety of chemical and physical treatments (e.g. grinding, fire polishing, and acid and base rinses) resulted in large changes in surface chemistry.