Development of Surface Coatings for Air-Lubricated,Compliant Journal Bearings to 650°C

Surface coatings for an air-lubricated, compliant journal for an automotive gas turbine engine were tested to find those capable of withstanding temperatures of either 540°C (1000°F) or 650°C (1200°F). Also, the coatings have to be capable of surviving the start-stop sliding contact cycles prior to rotor lift-off and at touchdown. Selected coating combinations were tested in start-stop tests at 14 kPa (2 psi) loading for 2000 cycles at room and maximum temperatures. Specific coating recommendations are: Cdo and graphite on foil versus chrome carbide on journal up to 370°C (700°F); NASA PS-120 (Tribaloy 400, silver, and CaF₂) on journal versus uncoated foil up to 540°C (1000°F); and chemcially adherent Cr₂O₃ on journal and foil up to 650°C (1200°F). The chemically adherent Cr₂O₃ coating system was further tested successfully at 35 kPa (5 psi) loading for 2000 start-stop cycles.     

高速钢刀具的C,N,O,B共渗处理

哈尔滨量具刃具厂传统的高速钢刀具处理工艺为氧氮化。近几年,为进一步提高刀具的耐用度,我们试验进行了C、N、O、B共渗处理,并添加稀土以催渗,取得了较好的结果,部分刀具已投入小批量生产。 一、共渗材料及方法 共渗用材料为W6Mo5Cr4V2高速钢,经1220～1240℃分级淬火和三次540～569℃×1h回火,硬度     

Tribological Properties of a C/C–SiC–Cu Composite Brake Disc

A life-size composite brake disc was produced from Si, carbon–carbon composite, copper, and phenol resin. The disc had an outer radius Ø380, inner radius Ø180, and thickness of 36 mm. Chopped carbon fibers were used to reinforce frictional and structural layers. To obtain a preform of each layer, resin and carbon-fibers were mixed and hot-pressed. The preforms were pyrolyzed, and bonded by hot pressing. Finally Si and Cu infiltration in vacuum atmosphere was carried out to obtain a C/C–SiC–Cu _x Si _y composite brake disc. The density of the disc was 2.17 g/cm³. The bending strength was 61 MPa. The heat transfer coefficients in vertical and horizontal directions were 30.7, and 85.2 W/m-°C at 25°C, respectively. Friction coefficients of the C/C–SiC–Cu _x Si _y brake disc were more stable than those of C/C–SiC brake discs. X-ray diffraction analysis showed that Cu formed a compound, Cu₃Si.     

NA1500型元素分析仪同时测定C,H,N,S

用ＥＡ１５００氮元素分析仪在１０分钟内同时测定了氮、碳、氢、硫，表密度高，线性好。     

Comparative study of the tribological behavior of self-lubricating W–S–C and Mo–Se–C sputtered coatings

Transition metal dichalcogenides (TMD) have been one of the best alternatives as low friction coatings for tribological applications, particularly in dry and vacuum environments. However, besides their deficient behavior in humid containing atmospheres, their extensive application has also been restricted due to their low load-bearing capacity. In order to overcome these problems, recently the alloying with C has been tried with the expectation of simultaneously improving the coatings hardness and reaching sliding contacting phases more convenient for achieving low friction in humid environments.The practical application of this concept was extensively studied with the W–S–C system, with the C addition being achieved either by reactive or co-sputtering processes. The best tribological results were obtained by co-sputtering from a C target embedded with an increasing number of WS₂ pellets. Excellent results were reached from the more than one order of magnitude increase in the coatings hardness up to friction coefficients which are close to those of the references of self-lubricating coatings: TMD for dry or vacuum atmospheres or C-based coatings for terrestrial sliding conditions.Following the good results achieved with W–S–C system, other TMDs systems have been envisaged to be studied. The main focus was placed on the Mo–Se–C system.In this paper, the general comparison between W–S–C and Mo–Se–C coatings is presented. The main effort is pointed on the tribological behavior of both systems when tested by pin-on-disk against steel counterpart balls under different testing conditions: applied normal loads, temperatures and relative humidity of the atmospheres. Both coatings were deposited by co-sputtering from a C target with a varying number of TMD pellets which could lead to C contents in the films in the range from 30  up to 70 at.%. A Ti interlayer was interposed between the films and the substrates for improving the adhesion.Typically, W–S–C films are harder than Mo–Se–C films. From the tribological point of view, W–S–C films are more thermally stable than Mo–Se–C films although the friction coefficients of these last ones are lower when tested in humid containing atmospheres.     

本题录按报刊首字拼音字母顺序排列:A,B,C,……

■C一 测控技术(月刊)2003年第1期自动测试系统(ATS)软件的发展及关键技术 李宝安等1海底天然大地磁场的探测邓明等5基于虚拟仪器的高压电气综合测控台的提出与设计蒋爱苏等9某型装甲车动态信息检测记录仪麻伟忠等12预测控制在步进梁加热炉先进控制中的应用研究汪开红等24单相三变在线式UPS全数字控制的设计与实现潘文辉28基于C8051F020单片机无人飞机控制系统硬件平台的设计与开发潘慕绚等30基于DSP的捷联导航计算机设计单茂华等31社址: 北京2351信箱(100022)'.电话:’010-65670337 传感器技术(月刊)2003年第1期仿生气体测量系统——…     

本题录按报刊首字拼音字母顺序排列:A,B,C,……

—C● 测控技术(月刊)2002年第12期微型飞行器测控系统的研究现状与发展 陈皓生等l航空维修检测技术的研究与发展新方向 器 莉等5关于微硅机械加速度计表头设计的几个问题刘云峰等7电动车电池电量测试及分析翁桂荣等1l利用数据融提高分布式检测参数的数据处理精度庄 严14光纤网络用于复合材料性能自诊断的研究杨红等17开关磁阻电动机参数测试王喜莲等20机场能见度仪光学头部温度控制 陈嘉艳等23开放式玻璃自动切割机计算机控制系统漫汁孟正大郝立等26复合肥分布式控制系统中通用配料系统的改计与实现祝学云等29基于嵌入式模块实现RS485与…     

元素分析仪同时快速测定C,H,Mo,Na（k）

本文介绍采用作者改进的柳本MC-2型碳氢元素分析仪并用X射线粉末衍射法代替化学分析法同时测定有机金属化合物中的C、H、Mo、Na(K)四元素,克服了原来化学分析法所存在的速度慢、操分繁琐等缺点,从而建立了新的快速分析方法。     

The 12C(α,α)12C nuclear resonance at 4.26 MeV and its application in RBS analysis of carbon content in thin films

The nuclear resonance in the ${}^{12}\text{C}\text{(αα)}{}^{12}\text{C}$ elastic scattering reaction at 4.26 MeV has been used to improve the sensitivity for carbon and to determine the depth distribution in thin films. The resonance response as a function of carbon content and α-energy, was studied using samples with known carbon thicknesses. The method has been applied in an investigation of the residual carbon on bare silicon wafers after the plasma cleaning of photo-resist layers.     

调整热处理工艺,保证C25进气门质量

C25进气门如图1所示,材料为4Cr10Si2Mo。热处理技术要求为:小头端部淬火长度为13～17mm,淬火后硬度48～58HRC,杆部整体氮碳共渗,渗层深度>O.003mm,心部硬度27～33HRC。     

ESI‐MS Study of Some C10 Iridoid Glycosides

Abstract

Five C₁₀ iridoid glycosides (shanzhiside methyl ester, lamalbide, lamiide, sesamoside, and 5‐desoxysesamoside) were examined by electrospray ionization mass spectrometry (ESI‐MS). Considerable differences were observed in positive ion and negative ion mode. Only the positive ion spectra were useful for molecular mass determination on the basis of molecular alkali metal adducts, with the exception of two iridoids containing all 5β‐OH, 7β‐OH and 8β‐OH groups. Fragment characteristics for distinct functionalities were observed. Chelation studies of each iridoid with three different alkali metals were also conducted.     

(Ti,W,Mo,Nb,Ta)(C,N)纳米固溶体粉的合成及性能

采用高能球磨-碳热氮化还原法合成了(Ti,W,Mo,Nb,Ta)(C,N)纳米固溶体粉,利用X射线衍射仪、扫描电子显微镜和元素分析仪等分析了还原温度和还原时间对粉体物相组成、晶格常数及碳氮含量的影响。结果表明:金属元素在Ti(C,N)中的固溶按难易程度排序为钽、铌、钨、钼;随还原温度的升高和还原时间的延长,固溶体粉的晶格常数、碳含量及粒径均逐渐增大;在1 500℃碳热氮化还原1 h后,可合成单相且平均粒径为100 nm的(Ti,W,Mo,Nb,Ta)(C,N)固溶体粉,其碳、氮质量分数分别为9.1%和7.2%。