Developments of work roll bite lubrication at SSAB Tunnplåt AB hot strip mill

In the strip rolling process friction is needed at first to pull the strip into the roll gap, otherwise slipping occurs. After the neutral plane however, where the velocity of the work roll equals the velocity of the strip, the friction stress alters direction to the opposite. If the friction stress after the neutral plane then is lowered, the total roll force will decrease. This can be done by a properly applicated oil- and water dispersion close to the work roll gap and between the roll cooling wipers. The technique and the key to a successful lubrication is a work roll surface which is as dry as possible. If the roll surface is not dry, neither large changes in the oil concentration, nor changes in the oil composition can make the lubricant stick to the roll surface. The lubricate was partly washed away by the water and only a small roll force decrease could therefore be measured. Only when the roll cooling water on the entry side of the work roll was set off on purpose, the roll force decrease was significant. Due to this result, further test were performed in an upstream stand in the hot strip mill. Here, the work roll wipers were modified and the roll was substituted by one with a larger radius and lubricated. The result was very slight or no water leakage at all. The roll force decrease was then much greater than before and close to those measured for the same reduction in the case of no entry water for the later stand. The electrical current in main drives and the roll wear in the lubricated stand could also be lowered significantly. In addition, the strip surface was greatly improved, under conditions with a high possibility of oxide residual contamination from the roll surface.     

镀锌DP780漏镀缺陷的成因分析与预防措施

为了解决热镀锌线生产高强度双相钢产品出现的表面漏镀问题,通过对缺陷的宏观与微观形貌以及成分进行分析,同时对漏镀的形成机理进行分析,确定影响表面漏镀的主要原因是双相钢中含有硅、锰等元素较多,容易发生选择性氧化,氧化物阻碍铁元素和锌液的铝热反应,形成漏镀。根据分析结果,采取提高炉区加热段露点和降低氢气含量的方法对漏镀进行预防。结果表明,同时提高炉区加热段露点和降低氢气含量能有效解决表面漏镀问题,取得了较好的实用效果,为进一步开发拓展更高级别镀锌双相钢提供了技术基础和理论依据。     

掺杂剂含量对钽粉性能的影响

分析了掺杂剂对电容器级钽粉性能的影响,重点分析了不同掺杂剂含量下钽粉的物理性能、化学成分及电性能的变化。研究表明,在相同的工艺条件下,随着掺杂剂含量的增加,钽粉的氧含量有增加趋势,钽粉的松装密度、费氏粒径呈降低趋势,-0.043 mm细粉含量有所增加,漏电流、容量及收缩率呈上升趋势、击穿电压呈下降趋势。     

混合时间对钽粉性能影响的研究

从钽粉混合时间方面分析了其对钽粉性能的影响,重点分析了钽粉在不同混合时间下物理性能、化学成分及电性能的变化。研究表明,随着混合时间的延长,钽粉化学成分基本不变,钽粉的松装密度、比表面积及-0.044 mm细粉含量呈上升趋势,费氏粒径呈降低趋势,其漏电流、损耗及收缩率也随之增加,而比容变化不大。     

化学腐蚀后的表面状态对硅片Fe沾污的影响

利用不同的酸腐蚀和碱腐蚀条件对硅片进行了腐蚀,分析了腐蚀后的硅片表面状态对Fe沾污的影响。实验结果表明,不同酸腐蚀条件的硅片经过以HF酸结尾的改进型RCA(Radio Corporation of America)清洗法清洗后,表面疏水性增强,相对不易附着Fe离子,而当酸腐蚀硅片表面经过SC-1溶液处理后,表面亲水性增强,附着的Fe离子较多,且难以通过超纯水冲洗去除;随着酸腐蚀硅片表面粗糙度的增大,表面吸附的Fe离子也增多。不同碱腐蚀条件的硅片去除量越小,表面残留的研磨造成的机械损伤层厚度则越大,损伤层厚度较大时,表面吸附的Fe离子也越多,且难以通过超纯水冲洗去除;在90℃下腐蚀40 s的硅片,由于去除量约为4.2μm,研磨过程中造成的表面损伤层沾污没有完全去除,残留在损伤层中的Fe沾污经过改进型RCA清洗后也无法去除,沾污会在退火过程中扩散进入硅片体内。     

线切割的电流密度对无取向电工钢切面的影响

对无取向电工钢进行电火花线切割实验，研究切割过程中不同的电流密度水平对切割面形貌的影响。采用三维测量激光显微镜对原始切割面的形貌进行观察，采用扫描电子显微镜观察经同等水平的超声振动方式处理后的切割面，以衡量表面附着层的附着能力。结果表明，随着电流密度水平的升高，切割面呈粗糙化趋势，由均匀光滑的小幅度凸起区和凹陷区逐渐替代为易于氧化的不规则台阶，台阶在高度方向的过渡区域为近垂直状；在过高的电流密度下，出现被氧化区包围的光亮近球形再凝固体。所以，高电流密度对控制切割面质量不利，采用较低电流密度的电火花线切割技术具有较高优势。     

Effects of NH3 annealing on interface and electrical properties of Gd-doped HfO2/Si stack

Effects of NH3 rapid thermal annealing(RTA) on the interface and electrical properties of Gd-doped HfO2(GDH)/Si stack were investigated.The process of NH3 annealing could significantly affect the crystallization,stoichiometric properties of GDH film and the interface characteristic of GDH/Si system.NH3 annealing also led to the decrease of interface layer thickness.The leakage current density of Pt/GDH/p-Si MOS capacitor without RTA was 2×10-3 A/cm2.After NH3 annealing,the leakage current density was about one order of magnitude lower(3.9×10-4A/cm2).The effective permittivity extracted from the C-V curves was～14.1 and ～13.1 for samples without and with RTA,respectively.     

非掺半绝缘LEC-GaAs晶片热处理工艺研究

为了获得高质量半绝缘砷化镓单晶片．有必要降低微缺陷密度，开展了晶片热处理工艺的研究．确定了晶片热处理的温度、时间、降温建率等一系列工艺参数，证实丁采用此项工艺能降低LEG-GaAs晶片的砷沉淀密度，郎AB-EPD，同时也保证了晶片的电学参数不受影响。通过对晶片热处理工艺过程和结果进行分析．给出了晶片热处理工艺理论模型的解释。     

Microstructure and Electrical Properties of Er_2O_3-Doped ZnO-Based Varistor Ceramics Prepared by High-Energy Ball Milling

Zinc oxide (ZnO) varistors exhibit highly nonlin-ear voltage-current (V-I) properties and it is ex-pressed bythe relationI=KVα,whereKis a constantandαis a nonlinear coefficient .They are extensivelyused as surge arresters in electric power lines ,such a…     

热处理时间和压制密度对氮化钽粉电性能的影响

用均相钠还原得到的纳米氮化钽粉在1 350℃进行不同时间的热处理,热处理后的粉末制成烧结体并进行阳极氧化过程。通过XRD和场发射扫描电镜分析了粉末的物相结构和形貌,研究了热处理时间和压制密度对氮化钽粉末电性能的影响。结果表明:热处理温度为1 350℃、热处理时间40min、压制密度约4g/cm时氮化钽阳极块体有较高的比容和较低的漏电流常数。     

Dry slipping steel–steel contact at high current density

The behavior of steel 3 in dry slipping under the action of high-density electric current is studied. In these conditions, the surface layer undergoes plastic deformation; its temperature rises; and new phases and structural defects are formed. That gives rise to a layer of secondary structures. The basic factor disintegrating the surface layer is the contact current density. The mean contact temperature and layer thickness of the secondary structures increase with increase in current density. The variation in wear rate and electrical conductivity with change in contact temperature is studied. The wear rate depends linearly on the contact temperature in normal wear. Catastrophic wear appears as sharp increase in the wear rate and simultaneous decrease in the contact electrical conductivity at 500—600°C. The thickness of the layer of secondary structures is 50 μm in these frictional conditions.     

Electrical characteristics of MOS capacitor using amorphous Gd2O3-doped HfO2 insulator

This work described the electrical characteristics of a kind of amorphous Gd2O3-doped HfO2 insulator for high-k metal-oxide-semiconductor(MOS) capacitors.Compared with pure HfO2,the doped HfO2 with an optimum concentration of Gd2O3 as MOS gate dielectric exhibited a lower leakage current,thinner effective oxide thickness and less fixed oxide charges density.The result indicated that Gd2O3 doping power of 60 W exhibited the best electrical characteristics,maximum capacitance,lowest leakage current of 9.35079...     

CeO2掺杂对HfO2栅介质电学特性的影响

采用磁控共溅射的方法在p-Si(100)衬底上沉积了掺杂和不掺杂CeO2的HfO2薄膜。通过X射线光电子能谱(XPS)研究了薄膜中元素的化学计量比及结合能,制备MOS结构并对漏电流及电容等电学性能进行表征。结果表明,掺入CeO2后,整个体系的氧空位生成能增大,氧空位数目减少,漏电流较纯HfO2下降了一个数量级,满足作为高k材料的要求。     

团化工艺对钽粉性能影响的研究

对采用团化工艺和未进行团化工艺处理的钽粉进行了分析比较,重点分析了其物理性能、化学成分及电气性能存在的差异。研究表明,采用团化处理的钽粉,其物理性能明显改善,颗粒均匀性好,漏电流、收缩率低,容量高,有利于提高压制块的成型性,降低烧结块的收缩率,提高电容器的容量,满足高比容、高压高可靠电容器的设计使用要求。     

密闭电解槽电积氯化钴生产电钴的工艺研究

在CoCl2体系中,采用密闭电解槽为电解设备,进行无隔膜、永久阴极电积钴试验。结果表明,该工艺避免了氯气泄漏,改善现场作业环境,在电流密度为500A/m2时,吨钴直流电耗为3 400kWh。     

Effect of current pulse frequency on the structure and properties of electric-spark alloyed coatings of the Ti - Al - N system

The mass transfer kinetics, composition, structure, and properties of coatings, formed by high-frequency electric-spark alloying of 45 and 40X steels with the Ti - Al (3:1, 1:1, 1:3) intermetallics and TiN - AIN (1:1) nitride were studied as a function of the current pulse frequency(ν = 1200 and 1600 Hz). A decrease in ν was found to lead to a higher mass transfer coefficient and higher microhardness and Young’s modulus of the coating as well. This is due to the decrease in the Ti/Al ratio on the surface. The phase composition of intermetallic and nitride coatings differed only insignificantly and did not depend on the value of ν. The main phases of the coatings were Fe - Ti - O and Al - Ti - O solid solutions. The nitride and intermetallic coatings had similar friction coefficients f and wear rates I (f = 0.26 and 0.28, I = 5.4 and 5.9 µm/km), despite the difference in their structure. We can assume that the coating phase composition which defines the composition of the secondary structure under dry friction, is the main factor controlling tribological behavior.     

双面抛光工艺中压力对300 mm硅片表面形貌的影响

利用非接触式光学轮廓仪研究了双面抛光过程中不同压力下300mm硅片表面形貌的变化，并通过Stribeck曲线进行了探讨。结果表明。双面抛光过程中机械作用的强度随着压力的变化而不同，从而影响抛光后的硅片表面形貌。当硅片表面与抛光垫之间的接触处于固，液混合接触区时，协调机械去除作用与化学腐蚀作用之间的关系，使之达到平衡，可以显著地降低硅片表面的微粗糙度和峰谷值。     

SiCl_4/TMAC-PC体系电沉积硅的研究

研究了硅在SiCl4/TMAC-PC体系中的阴极沉积过程,分析了电解质体系的热稳定性和电导率,研究电流密度、温度等因素对沉积层表面形貌的影响。结果表明,SiCl4的加入使得TMAC-PC体系热稳定性增强,电解质的电导率随温度的升高而增大,在318K、c(SiCl4)=0.5mol/L、电流密度i=15A/m2、电沉积时间3h条件下得到的沉积层致密,呈球形颗粒状。     

复压复烧对烧结减摩Cu-Ti3SiC2导电材料性能的影响

利用粉末冶金技术制备了10%Ti3SiC2颗粒增强Cu基减摩、导电材料。以200,400和500 MPa的压力对烧结试样进行复压,然后复烧,以提高材料的密度。通过测量试样的密度、硬度和电阻率,探索了复压复烧对材料性能的影响,并对试样进行了通电和不通电情况下的摩擦、磨损试验。结果表明,经400 MPa复压复烧后,材料的密度和硬度得到显著提高,密度由7.309 g·cm-3增加至7.712 g·cm-3,而硬度则达到HB 114,导电性能和减摩、抗磨能力也因此得到了改善,摩擦系数有所降低,磨损量减少了68%。与未带电的情况相比,带电时的摩擦因数相对较小,但磨损量则较大。在带电磨损实验过程中,摩擦副的温度升高使样品表面的铜基体部分氧化,并起到了润滑作用,从而降低了摩擦因数。     

Nd2O3-NdF3-LiF熔盐体系中电导率及钕溶解度的测定

研究了Nd2O3-NdF3-LiF熔盐体系中电导率及钕的溶解度，并根据实验数据拟合了回归方程，分析TN度、LiF浓度、Nd2O3浓度对两种物理性质的影响。结果表明，升高温度，提高LiF浓度以及降低Nd2O3浓度可以提高熔盐体系的电导率；而降低温度，降低LiF浓度以及提高Nd2O3浓度可以减少钕在熔盐中的溶解度。所得研究结果可为电解氟盐法生产钕选择合理的电解质成分提供依据。