等离子体增强电弧离子镀1Cr17Ni2不锈钢表面氮化/DLC涂层复合改性研究

在等离子体增强电弧离子镀设备中,用热丝增强放电的辉光等离子体对1Cr17Ni2马氏体不锈钢进行表面氮化处理。对氮化层的表面形貌、成分、相结构及性能进行了测试及分析。结果表明,氮化处理后不锈钢的表面硬度从3.67 GPa最高提升到9.25 GPa,并且在50μm深的范围内保持7.32 GPa以上的硬度,改性层内有CrN和Fe_2N新相生成是硬化的主要原因,不过与基体相比,摩擦系数仅从1.1略微降低到0.9。在氮化预处理的基础上,再一体化用碳靶阴极弧等离子体对1Cr17Ni2钢进行氮化/DLC涂层复合改性处理,对表面DLC涂层改性层的品质及性能进行了测试与分析。结果表明,复合改性处理后,因表面得到1.5μm厚的高品质的DLC涂层,及氮化预处理使得表面硬度有梯度提升,使1Cr17Ni2钢的整体表面硬度进一步提高到17.06 GPa,且摩擦系数显著降低到0.08。     

离子能流密度对AISI304不锈钢氮化层摩擦性能的影响

采用低温等离子体氮化技术,对AISI304不锈钢进行表面氮化处理。考察了离子能流密度对不锈钢氮化层性能的影响。运用X射线衍射、扫描电镜和显微硬度计等分析手段对氮化层的物相组成及表面硬度进行分析及测量;利用球-盘摩擦实验在干摩擦条件下对氮化层的摩擦磨损性能进行测试。结果表明:AISI304不锈钢经低温等离子体氮化处理后,形成单一高氮面心立方相γN。在氮化处理过程中,离子能流密度受工作压力及基片负偏压影响较大。离子能流密度变化能显著影响不锈钢氮化层的摩擦性能,随着离子能流密度的增加,氮化层显微硬度增大,摩擦系数减小,耐磨损性能上升。     

辉光离子氮化的物理基础与实践

前言 在学院各级党组织领导下,工农兵学员、工人师付和革命教师一起群策群力,使辉光离子氮化新工艺逐渐完善。这是以阶级斗争为纲,贯彻毛主席的教育路线的又一丰硕成果。 1932年德国B.Berghaus首先利用辉光放电发明了离子氮化法。但当时还未掌握稳定大电流辉光放电的技术。随后W. Weizel和 B.Brant等人进一步研究,辉光离子氮化才在生产上得到应用,现在国内外在热处理工业中都很重视。 辉光离子氮化是使含氮气体电离,N离子在电场作用下对工件表面轰击加热工件,并被吸附向里扩散形成氮化层。这个工艺过程与辉光放电有密切的关系。但国外文…     

LD系列辉光离子氮化设备简介

我厂为加速这项新工艺的推广应用,有利于促进机械工业产品质量的提高,使用寿命的增长,在国内兄弟单位、科研部门、大专院校无私的帮助下由研制到小批生产辉光离子氮化设备,现已基本形成系列生产。 ’为满足需用单位对设备结构、性能、技术数据等有关情况的了解而编此简介,供参考。 由于水平所限,难免有缺点和错误,我们恳切希望提出宝贵意见,以便今后更改,补充。 辉光离子氮化是近几年在国内发展起来的一种新的氮化工艺,其特点如下: 1、离子氮化周期可缩短50～80% 2、离子氮化能抑制氮化表面白色脆层的形成,脆性能达到一级。 3、离子氮化变形…     

激光重熔对NiCrBSi等离子喷涂层显微结构和性能的影响

1Crl8Ni9Ti不锈钢表面的NiCrBSi等离子喷涂层存在孔洞及与基体结合差等缺陷,为此进行了激光重熔处理.采用扫描电镜和显微硬度压痕仪分别对涂层的显微结构和力学性能进行了对比研究,采用SRV试验机评价了涂层激光重熔前后的滑动摩擦磨损性能,研究了激光重熔对NiCrBSi等离子喷涂层结构和性能的影响.结果表明:经过激...     

表面应变强化对不锈钢应力腐蚀开裂的影响

本文利用表面应强化(喷丸)处理的方法来改善奥氏体不锈钢(1Crl8Ni9Ti)和马氏体不锈钢(Cr17Ni2)的SCC倾向性,其主要结果如下: 1. 表面应变强化处理能够显著地改善奥氏体及马氏体两种不锈钢的抗SCC性能。 2. 表层内塑变诱生的具有高位错密度的马氏体及残余压应力是提高奥氏体不锈钢SCC抗力的两个主要因素。 3. 表层内高位错密度的马氏体及残余压应力是提高马氏体不锈钢SCC抗力的两个主要因素。 4. 应力腐蚀条件下亚稳态奥氏体不锈钢的SCC,实质上是塑变诱生马氏体的类解理断裂。     

不同表面状态的32Cr2MoV的滑动摩擦试验比较

对复合镀膜处理的32Cr2MoV、离子氮化的32Cr2MoV和离子氮化后机械抛光的32Cr2MoV进行了滑动摩擦试验,并对比分析了三者的组织和显微硬度.结果表明,3种试样表面都呈现磨粒磨损的特征.在3种处理当中,复合镀膜的32Cr2MoV表面粗糙度比镀膜前高,但是表层0.2mm范围内镀膜后的显微硬度最高,摩擦力、摩擦系数、磨痕宽度、磨损量较离子氮化试样和离子氮化后抛光试样低,磨痕较浅,耐磨性最好.从观察结果还发现,离子氮化试样经过表面抛光后虽然表层硬度下降,但是其粗糙度远远低于抛光前,弥补了硬度下降对耐磨性的不利影响,使得其耐磨性有所提高.     

离子氮化及其在精密仪器制造中的应用

用LD—50型辉光离子氮化设备进行了离子氮化试验,并将其试验结果与等温气体氮化、二段气体氮化、催渗二段气体氮化进行了工艺和效果的比较。最后简介了离子氮化的应用。     

铀表面脉冲辉光等离子氮化初步研究

采用脉冲辉光等离子体离子氮化技术对贫铀表面进行了氮化处理,采用俄歇电子能谱(AES)对氮化层进行元素深度剖析,采用X射线衍射(XRD)、扫描电子显微镜(SEM)对氮化层组织结构进行了分析表征。结果表明:脉冲偏压-900 V,工作氮分压50 Pa、100 Pa,氮化时间2.5 h~4 h下在贫铀表面能获得约20μm厚的氮化层,氮化层为U2N3的单一立方结构且均匀致密,脉冲辉光等离子氮化技术能在贫铀表面实现氮化。     

土壤中硫酸盐还原菌对1Crl3不锈钢腐蚀的影响

利用交流阻抗测试、扫描电镜观测、表面能谱分析、失重法以及微生物分析等方法，研究了硫酸盐还原菌(SRB)对在不同C1^-含量的土壤中的1Crl3不锈钢腐蚀的影响．结果表明：随着土壤中C1^-含量的增大，1Crl3不锈钢的腐蚀速率和最大点蚀深度随着土壤中C1^-含量的增加而增大，当C1^-的含量增大到1．0％时达到最大值．与灭菌土壤相比，在接菌土壤中1Crl3不锈钢腐蚀速率和最大点蚀深度大，说明硫酸盐还原菌和C1^-的共同作用增大了土壤中1Crl3不锈钢的点蚀敏感性．1Crl3不锈钢未发生点蚀时阻抗图谱表现为单容抗弧，发生点蚀时阻抗图谱表现为有两个时间常数的双容抗弧．     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。