光学表面光洁度评述

本文叙述了光学表面光洁度概念、重要性、评定规范、检测方法和仪器装置,以使有关人员对表面质量评定问题引起足够重视,并对出口的光学零件严格检验,以使我们的产品质量得到保证而尽快参与国际竞争,出国创汇或承接国外加工订货。文中还介绍了有关国家标准和美国MIL-0-13830A规范。     

Real time observation of viscoelastic creep of a polymer coating by scanning probe microscope

We have developed a new technique of using the scanning probe microscope to measure the marring resistance that is a very desirable characteristic of clearcoats used in the automotive industry. With its high resolution, SPM can also be used to investigate the marring mechanism, and provide useful information in development of highly mar resistant coatings. In this paper, we will report a real time observation of viscoelastic creep which can result in a partial or complete healing of a marred surface. Based on the experimental data, a preliminary analysis of the recovery rate, recoverable deformation, and permanent deformation is presented. This revised version was published online in June 2006 with corrections to the Cover Date.     

An Improvement on Adhesion of Sputtered TiC Coating to Steel Substrate

Introducing N_2 during sputtering andpre-oxidation of substrate were investigatedto improve the adhesion of sputtered TiC coatingto steel substrate. The results show thatyeactive gas N_2 increases the adhesion of TiCcoating to steel because of a graded interfaceexisting between coating and substrate. Theinteraction of discharge plasma with the surfaceof substrate was discussed. Pre-oxidation ofsubstrate is effective for improving the adhesiondue to the fomation of FeTi0_3 which appearedas an inteylayer between coating and pre-oxidizedsubstrate.     

连铸坯表面振痕的控制

分析了连铸坯表面振痕的形成及其对铸坯质量的影响，探讨了减小连铸坯表面振痕深度的工艺措施，提出了控制连铸坯表面振痕深度的限度。     

An estimation method on failure stress of micro thickness Cu film-substrate structure

The failure of thin film-substrate structure occurs mainly at the thin film or the interface. However, the characterizing and estimating methods of failure stress in thin film are neither uniform nor effective because there are some complex effects of such as size, interface and stress state on the failure behavior of thin film-substrate structure. Based on the scanning electron microscope (SEM) in-situ investigation on the failure models of the Cu thin film-substrate structure and the nano scratched testing results, the failure stresses in different thicknesses of the Cu film-substrate were characterized, which were compared and confirmed by other methods, such as Stoney formula and other empiric equations. These results indicate that the novel estimating method of failure stress in thin film based on the critical wavelength of surface unstable analysis is better than other methods. The main reason is that the novel estimating method of failure stress in meso thickness film fully considered the effect factors of free surface unstable behavior and elastic anisotropy of thin film. Therefore, the novel estimating method of failure stress assists people to understand the critical interfacial strength and to set up the failure criterion of thin film-substrate structure. Supported by the National Natural Science Foundation of China (Grant No. 10772091) and National Basic Research Program of China (Grant Nos. 2004CB619304-5, 2007CB936803)     

Quantitative modeling of scratch-induced deformation in amorphous polymers

In order to predict scratch performance of polymers, the present study focuses on quantitative assessment of various scratch-induced deformation mechanisms based on a set of model amorphous polymers via numerical modeling. A modification of Ree-Eyring theory is used to account for the rate dependent behavior of the model polymers at high strain rates using the experimental data obtained at low strain rates. By incorporating the rate and pressure dependent constitutive and frictional behaviors in the finite element methods (FEM) model, good agreement has been found between FEM simulation and experimental observations. The results suggest that, by including appropriate constitutive relationship and frictional model in the numerical analysis, the scratch behavior of polymers can be quantitatively predicted with reasonable success. Usefulness of the present numerical modeling for designing scratch resistant polymers is discussed.     

热轧钢卷平整生产线挫伤缺陷的原因分析

随着用户对热轧钢带板形质量要求的不断提高,热轧带平整工序在板形质量改善中的应用越来越多。但是,热轧平整工序也带来了大量的表面质量缺陷,以挫伤缺陷出现最为广泛,对板带表面质量影响最为严重。通过对挫伤缺陷形貌的分析,提出挫伤缺陷是由相互挤压的带钢的相对滑动导致局部金属产生剪切滑移而形成的,带卷产生层间滑动的原因是相邻层间的静摩擦力不足以抵消带卷的转动惯量,从而产生相对滑动。带卷板面的不平滑区域与相邻平滑区域存在明显的半径突变,滑动时在与相邻层的接触面区产生足够的压力,导致局部金属产生剪切滑移。同时提出了相应的预防措施。     

Mechanical and scratch behaviors of polyrotaxane-modified poly(methyl methacrylate)

The mechanical and scratch behaviors of polyrotaxane (PR) modified poly(methyl methacrylate) (PMMA) were investigated. PR is a necklace-like supramolecule with rings threaded onto a linear backbone chain that is capped by bulky end groups. Cyclodextrin (CD) serves as the ring structure and can be functionalized to induce specific interactions with the hosting polymer matrix. To systematically investigate the effect of CD functionalization on the mechanical properties of PMMA, PR with polycaprolactone (PCL) grafted chains on CD, and PR with methacrylate functional groups at the terminal of the PCL grafted chains on CD were chosen for this study. Tensile and compressive true stress–strain tests, ASTM scratch test, and coefficient of friction measurements were conducted to fundamentally understand how PR influences the mechanical and scratch behaviors of PMMA. Additionally, dielectric relaxation spectroscopy and dynamic mechanical analysis were conducted to explore how PR influences the relaxation dynamics of PMMA. The above findings suggest that the methacrylate functional group on PR induces favorable molecular interactions with PMMA matrix, leading to enhanced molecular cooperativity during deformation, which in turn improves tensile and compressive properties and achieves greatly improved scratch resistance.     

Nanoscratch behaviors of La0.7Sr0.3MnO3+δ thin films

The nanoscratch behaviors of La0.7Sr0.3MnO3+δ films, which were deposited with ratio of O2/(O2+Ar), ranging from 4.4% to 45.6%, by DC magnetron sputter, were investigated by a nanoindentation technique. The results indicated that the friction coefficient between the films and the diamond tip depended on the loading critical load. The friction coefficient was about 0.08-0.12 when the loading normal load was less than the loading critical load. The films displayed excellent elastic recovery after unloading. When the loading load was larger than the loading critical load, plastic deformation and ploughing appeared for the films. The friction coefficient was about 0.43 when the film was damaged completely. The suitable decrease in ratio of O2/(O2+Ar) could improve the nanoscratch resistance of the films. The film deposited with O2/(O2+Ar)=25% possessed better scratch resistance due to good elastic recovery, high nanohardness, and critical load. The loading critical load of the film was larger than 80 mN.     

Nanomechanical evaluation of nickel-titanium surface properties after alkali and electrochemical treatments.

In this paper, the suitability of alkali treatment followed by heat treatment at 600 degrees C, and spark oxidation for nickel-titanium, intended for medical applications such as pins, wires and clamps, was evaluated on the basis of nanomechanical and wear testing. In addition, the chemical composition and topography of the surface layer, wetting ability, corrosion resistance and influence of the heat treatment on structure of the alloy were also investigated. The results showed that the highest hardness was observed for alkali-treated samples, and this could be correlated with the structure of the sample that contained martensite and a higher phase transformation temperature. This treatment caused a very large increase of nickel in the top layer and decreased resistance in pitting corrosion. These results disqualified the treatment to be considered as useful for medical applications. On the other hand, the hardness of the oxidized samples was at the same level as that obtained for ground reference samples. Moreover, the oxide layer was enriched with phosphorus, and it was predominantly composed of TiO2 and phosphorus oxides. This 3.1 microm thick layer had good adhesion to the substrate as indicated by scratch testing and wear resistant in nanowear testing. However, the oxidation did not significantly increase the corrosion resistance of the alloy compared with reference samples.