多弧离子镀TiN/TiCrN/CrN多元多层复合膜的制备及性能研究

采用XH-800多弧离子镀设备在硬质合金刀具表面制备TiN/TiCrN/CrN多元多层复合膜.利用XRD、SEM、显微硬度计、多功能材料表面性能测试仪等对其组织结构与性能进行了研究.结果表明:膜层表面均匀,未出现龟裂现象,色泽光亮度好;膜的相结构组成为TiN和Cr2N,随着Cr靶电流的增大,TiN的择优取向由(200)向(111)转变,膜层出现单质Cr;膜层厚度为5.02μm,具有明显多层特征;显微硬度2536 HV;结合力65 N.     

不锈钢纤维多孔材料的准静态压缩性能

以直径为■8,20μm的316L不锈钢纤维毛毡为原料,通过烧结工序制备了孔隙率为64.3%~89.3%的不锈钢纤维多孔材料,采用INSTRON测试仪测试了其准静态压缩性能,利用Vic-3D非接触应变测试仪获得了材料的静态压缩应力应变曲线,利用高速摄像机拍摄了材料的静态变形过程,系统分析了孔隙率、纤维直径、材料厚度对多孔材料弹性模量和能量吸收值的影响规律。研究表明不锈钢纤维多孔材料的准静态压缩应力应变曲线分为3个阶段,即弹性变形阶段、弱变形强化阶段和强变形强化阶段。随着孔隙率的降低,多孔材料的弹性模量和能量吸收值逐渐增加,其弹性模量和能量吸收值最大分别达到542 MPa和27.7 MJ/m~3(孔隙率为64.3%)。     

N_2流量对HIPIMS/DCMS共沉积制备TiAlCrN涂层结构及性能的影响

利用高功率磁控溅射与直流反应磁控溅射共沉积技术制备了不同N_2流量下的TiAlCrN复合硬质涂层。采用X射线衍射仪(XRD)、薄膜综合性能测试仪以及大气球盘摩擦磨损试验机分析测试了涂层的微观组织结构、力学性能及摩擦学性能。结果显示:随N_2流量的提高,涂层沉积速率先上升后下降;XRD测试表明增加N_2流量可有效抑制h-Al N相的生成,并且改善了涂层的结晶性能;同时,表面粗糙度先下降后升高,最小值可达45.7 nm;涂层硬度逐渐上升,而弹性模量在取得最大值后呈下降趋势,最大值分别为31.2和423.8 GPa;划痕临界载荷在N_2流量为250 m L/min时获得最优值5.5 N。摩擦学性能方面,随N_2流量的提高,涂层磨损率先下降后上升,最小值为2.6×10~(-17)m~3/N·m。由此可见,在一定范围内调节N_2流量可显著改善涂层的强度及耐磨损性能。     

中频磁控溅射TiAlN薄膜的制备与性能研究

采用中频非平衡磁控溅射离子镀技术在硬质合金基体YG6上制备TiAlN薄膜。利用XRD、EDS、体式显微镜、显微硬度仪和多功能材料表面性能测试仪等对其组织结构以及性能进行了研究分析。结果表明:低Al靶功率时,膜层以TiN、TiC形式存在,TiN的择优取向面(111),显微硬度与偏压有关;高Al靶功率时,膜层主要存在Ti3AlN、AlN相,Ti3AlN相沿(220)晶面择优取向;膜层结构致密均匀,N原子与金属原子比接近1:1;膜层厚度为1.93μm;显微硬度3145HV;结合力85N。     

用空间电荷限制电流法测量非晶硅基薄膜的隙态密度

利用常规的层状结构的空间电荷限制电流法,测得了具有一定厚度 d 的 GD-a-Si_(1-x)C_x∶H 和 GD-a-Si_(1-x)N_x∶H 膜不同含量 x 时的隙态分布 N(E):对 GD-a-Si_(1-x)C_x∶H 膜(d(?)1μm),当 x 为0、0.1、0.8时,平衡费米能级附近处的隙态密度 N(E_(?)~o)分别为2×10~(15)、4×10~(15)、6.2×10~(16)/cm~3·eV,对 GD-a-Si_(1-x)N_x∶H 膜(d(?)1μm),当 x 为0、0.05、0.2时,N(E_F~o)分别为2×10~(15)、3×10~(15)、4.5×10~(16)/cm~3·eV;得到了 GD-a-Si∶H 膜的隙态分布与膜厚度的关系,发现随着膜厚度的增加 N(E_F~o)在减小,当 d<1μm 时,N(E_F~o)约为10~(16)/cm~3·eV 的数量级,当 d>1μm 时,N(E_F~o)约为10~(15)/cm~3·eV 的数量级。对共面电极结构的样品,用温度调制空间电荷限制电流法(TM-SCLC),测得了 GD-a-Si∶H 膜的隙态分布,并对光处理前后的样品进行比较,发现强光照后存在有光诱导效应。我们对所得结果作了初步说明。     

火炮身管内壁磁控溅射氮化物层的性能

为了提高火炮身管的力学硬度和弹性模量,在PCrNi3 Mo钢表面磁控溅射了TiAlN,CrAlN 2种氮化物防护层.利用激光共聚焦显微镜、X射线衍射仪(XRD)对2种溅射层的形貌及结构进行了表征,采用纳米压痕仪测试了基材与2种溅射层的硬度和弹性模量.结果表明:CrAlN层表面相对平整光滑致密,表面粗糙度较小(Ra=0.004～0.006μm),TiAlN层表面粗糙度相对较大(Ra=0.005 ～0.021μm);CrAlN层表面生成的主晶相为CrN,TiAlN层表面生成的主晶相为TiN,2种晶相分别沿(110)和(200)面呈现择优取向;CrAlN层硬度和弹性模量分别为20.39,288.8 GPa,TiAlN分别为14.51,267.70 GPa,较基材(5.57,258.00 GPa)均有显著提高,其中CrAlN层提高最为显著.     

α-氧化铝粒径和形貌对GIS用环氧树脂复合材料介电性能和热性能影响的研究

采用不同尺度和形貌的α-氧化铝(α-Al_2O_3)复配制备环氧树脂绝缘复合材料,运用扫描电子显微镜观察复合材料形貌,运用介电强度测试仪、动态机械热分析仪、激光热导仪等研究α-Al_2O_3复配对材料介电性能和热性能的影响。结果表明:多尺度无规α-Al_2O_3(12μm/2μm)复配提高了环氧树脂的击穿强度、击穿稳定性及玻璃化温度,热导率略有下降;小粒径球形α-Al_2O_3(2μm)与无规α-Al_2O_3(12μm)复配,热导率有所提高,但是降低了环氧树脂的击穿性能及玻璃化温度。这主要归因于不同尺度和形貌的α-Al_2O_3和环氧基体间的界面和体系间的空隙不同。     

透红外氟铝酸盐玻璃通过中国科学院鉴定

优质、大尺寸透红外玻璃是国防工业急需的关键材料。中国科学院上海光学精密机械研究所经多年努力,研制成功了透红外氟铝酸盐玻璃,其主要性能: (1) 透光范围:0.35—7μm,其中0.42—5.2μm波段透过率大于90％(3mm厚样品) (2) 光学性能:折射率n_d=1.426,阿贝数v_d=97 (3) 化学稳定性:耐潮A级,耐酸3级(按GB903—65),水中浸泡24小时未发现明显水浸蚀痕迹; (4) 热学性能:软化温度450℃,热膨胀系数(20—120℃) 146×10~(-7)/℃ (5) 机械性能:弹性模量70.2GPa     

可控阴极弧制备的梯度及调制多层CrN/Cr薄膜的组织结构和力学性能研究

采用可控阴极弧的沉积方法在GCr15基体上制备了梯度和调制多层结构的氮化铬/铬(CrN/Cr)薄膜,对不同的CrN/Cr薄膜的组织结构、力学性能和耐磨性能进行了研究。通过扫描电镜、能量散射谱、X射线衍射、纳米压痕、划痕试验、微摩擦磨损测试仪及形貌测试仪对薄膜的组织结构、成份、力学性能、结合强度及耐磨性能进行了分析。结果表明:制备的薄膜厚度约5.5μm,梯度结构及调制多层CrN/Cr薄膜呈现明显的立方CrN(111)(200)取向,薄膜力学性能(包括硬度,模量,结合强度等)及耐磨性能均与不同的结构及调制周期相关。梯度结构的CrN/Cr薄膜硬度达到25 GPa,结合强度55 N,磨损率为32.754×10-6mm3/N·m,力学及耐磨性能明显优于其它多层结构,说明梯度结构可有效地改善CrN/Cr薄膜的性能。     

新型耐热弹性合金弹性性能的研究

对耐热弹性合金材料的抗松弛性能、弹性模量、弹簧扭矩进行了重点分析和研究。研究了合金在不同热处理工艺下对松弛率力学性能的影响,以及弹簧扭矩随扭转角度的变化情况。结果表明,研制的弹簧抗松弛性能优于进口产品;弹簧的扭矩性能满足国家重点试验机的要求;在达到扭矩值6.86N.m后回转90°,测得最低扭矩值测得为5.12N.m;普遍回转90°的扭矩值为5.45～5.65N.m。弹型模量温度系数βE计算得出为3.91×10-4/℃。计算610℃时弹性模量相对室温的变化为:ΔE/Eo=23.78%。     

进出口食品中亚硫酸盐测定方法的探讨

亚硫酸盐是一种用途广泛的食品添加剂,若摄入过多则对人体的健康产生损害。本文对国内外食品中亚硫酸盐的常用检验方法进行深入探讨,比较了各类检测方法的优缺点,并在检疫工作实际中加以灵活应用,效果良好。     

Evidence for the invalidity of the Bradford law for the single scientist

On the basis of a previously proposed method using meta-informations accumulating during SDI from an international system of the INIS-type, it is investigated, how the scientific journal rank distribution of a research institution, for which the Bradford law is valid, is composed of the single scientists' journal distributions. In this transition from a macroscopic into a microscopic field of scientific communication evidence was found for the invalidity of the Bradford law for the journal rank distribution of a single scientist. This effect seems to confirm a fundamental qualitative difference of both fields of scientific communication.     

鞋类通用检验方法的结果分析

成鞋检验方法中的物理力学性能指标主要有耐折、耐磨和剥离强度,这三项指标的检验结果常常存在着较大的波动,甚至有的数据相差很大,影响了质量判断的准确性.     

Concepts of ISO for the monitoring of workers for internal exposure and the present approach for the dose assessment

Besides ongoing developments in the dosimetry of incorporated radionuclides, there are various efforts to improve the monitoring of workers for potential or real intakes of radionuclides. The disillusioning experience with numerous inter-comparison projects identified substantial differences between national regulations, concepts, applied programmes and methods and dose assessment procedures. Measured activities were not comparable because of severe differences between measuring frequencies and methods, but also results of case studies for dose assessments revealed differences of orders of magnitudes. Besides the general common interest in reliable monitoring results, at least the cross-border activities of workers (e.g. nuclear power plant services) require consistent approaches and comparable results. The International Standardisation Organisation (ISO) therefore initiated projects to standardise the monitoring of workers, the requirements for measuring laboratories and the processes for the quantitative evaluation of monitoring. This presentation is intended to give an introduction into some important aspects addressed in these standards: the need for a monitoring programme, the design of a monitoring programme: methods and intervals, reference levels and approaches for dose assessments.     

Variational Principle for the Temperature Problem of the Elasticity Theory for Stresses

The variational formulation of a problem is frequently used in strength analysis of parts and structural elements. The authors present a variational principle whose Euler's equations are the differential equations of thermoelasticity for stresses.     

Measurement system for evaluation of the muon chambers for the LHCb experiment

In a detector with the complexity of the LHCb, where only for the muon system more than 1300 chambers, divided into 20 different types, will be used, resulting on more than 120 k channels to be readout, it is of crucial importance to study the many types of chambers to create a complete knowledge of the detector operation and to guarantee a high-quality performance during the experiment. To make it possible, a complete setup was built and a C++ based software was developed to carry out a set of measurements on the full-equipped chambers of the LHCb muon detector. The setup is made of front-end control electronics, high-voltage supply and acquisition circuitry while the software, running on a PC, remotely controls each element of the system and implements a number of automatized procedures to assess the main characteristics of the chambers.The main advantages of this system are its versatility and speed of measurement which are crucial to the experiment since there is the need to characterize every single chamber before final installation. Moreover, in this work it was proposed to measure the starting knee of the high-voltage operational plateau without the use of an external trigger by making use of the internal structure of the chambers. Two laboratories were prepared at CERN (European Laboratory for Particle Physics) to receive this system; one used to test chambers arrived from the CERN itself and the PNPI (Petersburg Nuclear Physics Institute) production sites, and one to test the chambers arrived from the INFN (National Institute of Nuclear Physics) production sites. In this document, the hardware and software setup will be presented together with the measurement-oriented implementations.     

Numerical-experimental method for the construction of the complete fatigue curve for metals

We propose a numerical-experimental method for constructing the fatigue curves of metallic materials, based on the use of only two values of the fatigue limit σ_a for N = 10³ and 10⁵ as well as of certain physical analogs. This method ensures more than satisfactory agreement of calculated estimates with experimental data. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 6, pp. 94–100, November–December, 2007.     

Strategy for the future

The Pennsylvania State University at University Park is one of the most dominant materials research institutions in the US with more than $65 million in sponsored materials research funding for fiscal year 2002¹, and possessing more than twice the number of most highly cited researchers in materials science of any university worldwide². The Materials Research Institute (MRI), an interdisciplinary consortium at Penn State, integrates and leads these activities across the university and maintains world-class facilities to support them. More than 200 faculty and 500 graduate students are engaged in materials research, along with nearly 200 postdoctoral and visiting scientists. This high concentration of faculty and experts at the university has facilitated the formation of cohesive teams to meet specific materials research goals.