Density of Liquid Ni-Cr Alloy

The density of liquid Ni-Cr alloy was measured by a modified sessile drop methold.The density of liquid Ni-Cr alloy was found to decrease with increasing temperature and Cr concentration in the alloy,The molar volume of liquid Ni-Cr alloy increases with increasing the Cr concentration in the alloy ,The molar volume of Ni-Cr alloy determined in the present work shows a positive deviation from the linear molar volume.     

基于MEMS工艺的微起爆器性能研究

针对MEMS火工品低能化、集成化技术要求,设计了一种基于MEMS工艺的微起爆器,通过仿真计算获得了基体材料、换能元材料、火工药剂与微起爆器起爆性能的影响规律,确定了微起爆器的结构参数;通过MEMS工艺完成微起爆器一体化集成制作,对结构参数以及起爆性能进行了测试,结果表明结构尺寸与设计尺寸误差小于6%;微起爆器发火电压小于3V,装药直径1mm、装药量2.0mg时,可以可靠起爆CL-20炸药,实现了低能化、集成化的要求,为MEMS火工品提供技术支撑。     

激光钎焊多层金刚石磨粒Ni-Cr合金成形工艺研究

为实现多层金刚石磨粒逐层激光钎焊成形,从单道扫描到单层扫描,再到多层扫描,系统研究了镍铬合金与金刚石磨粒的多层激光钎焊工艺。通过提取钎焊道与层的截面成形特征参量,对钎焊层截面成形质量进行参数化评价,并结合钎焊层表面形态,对钎焊层综合成形特性进行评价和讨论,研究了工艺参数对钎焊成形的影响。研究结果表明：激光功率与扫描速度是影响钎焊成形的重要因素,不仅影响着合金粉末的熔合程度、熔池宽度,还影响金刚石的分散状态和钎料对金刚石的浸润包裹性,最终影响钎焊层的平整性。当道与道之间的搭接率为30%~40%时,钎焊成形质量较好。在采用逆向扫描策略,扫描道数为10、固定激光功率为700 W、扫描速度为15 mm/s、光斑直径为1.5 mm、搭接率为30%的条件下,实现了多层磨粒的激光逐层钎焊成形,钎料对金刚石浸润包裹充分,钎焊层中间区域平整连续,整体成形质量好。     

变形链球菌在几种不同合金表面的黏附实验研究

目的：比较在相同培养条件下,变形链球菌在5种临床常用合金材料（镍铬合金、钴铬合金、金钯合金、74％金合金、86％金合金）表面的黏附情况。方法将5种合金、材料的试件（各5个）逐级打磨、抛光至粗糙度无差异,灭菌后分别置于含有变形链球菌的培养基内厌氧培养,48 h 后检测试件表面菌落生长数量。结果合金材料表面黏附的变形链球菌量：镍铬合金＞钴铬合金＞金钯合金＞74％金合金＞86％金合金。74％金合金组与86％金合金组间变形链球菌量差异无统计学意义（P ＞0．05）,其余各组间差异均有统计学意义（P ＜0．05）。结论贵金属修复体在控制变形链球菌黏附方面优于普通合金修复体,临床上可考虑尽量选用贵金属材料进行修复。     

The Effects of Reactive-Element,Ion-Implantation-Induced Amorphous Layers on the Oxidation of Co-12Cr and Ni-12Cr Alloys

Nickel-chromium (Ni-12Cr, wt.%) andcobalt-chromium (Co-12Cr, wt.%) alloys were ionimplanted with 150 keV yttrium to fluences that rangedbetween 2 × 10¹⁶ and 1 ×10¹⁷ ions/cm². The influence ofthe implantation on the microstructure of the alloy wasdetermined. The effect of the highest dose implantationon the alloys' oxidation response at 1000°C, 48 hrwas measured. Both alloys contained an amorphous surface phase as a result of this fluence and one ofthe effects of oxidation was to recrystallize theamorphized alloy in the first few minutes of oxidation.The lower doses of 2 × 10¹⁶ions/cm² were sufficient to cause amorphization of both the Ni-12Cr andthe Co-12Cr. The implantation reduced the isothermalmass gain by a factor of 25% for the Ni-12Cr, but had anegligible effect on the Co-12Cr alloy. Short-term oxidation experiments at 600°C showed viatransmission electron microscopy that, in the absence ofthe yttrium implant, the Ni-12Cr alloy forms NiO in thefirst minute of oxidation and the Co-12Cr alloy forms CoO and CoCr₂O₄.The implanted Ni-12Cr, on the other hand (1 ×10¹⁷Y⁺/cm²), formsrecrystallized Ni-Cr, Y₂O₃, andNiO in the near-surface region, while the implantedCo-12Cr alloy forms CoO, CoCr₂O₄, and a recrystallized intermetallic alloy fromthe amorphized region.     

Effect of Ni-Cr Layer on Adhesion Strength of Flexible Copper Clad Laminate

In this study, the effect of a Ni-Cr layer on the adhesion strength of flexible copper clad laminate (FCCL) was evaluated after thermal treatment. The changes in the chemical composition, morphology, and adhesion properties were characterized by scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and 90 deg peel test. The results showed that both the peel strength and thermal resistance of the FCCL increased with increasing Cr ratio. The thermal treatment of the FCCL increased the proportion of C-N bonds and reduced that of the C-O and carbonyl (C=O) bonds in the polyimide. The roughness of the fracture surface decreased with increasing thermal treatment temperature and holding time. The chemical function and roughness of the fracture surface were affected by the Ni-to-Cr ratio.     

Ni-Cr/陶瓷连接界面残余应力有限元分析

采用有限元法分析Ni-Cr合金与陶瓷连接冷却过程中界面残余应力形成的大小和分布特征.结果表明,Ni-Cr合金与陶瓷存在较大的线膨胀系数差,在界面间会产生较大的残余应力,并因为边缘效应在拐角处产生应力集中,残余应力最大值出现在Ni-Cr/陶瓷界面的近瓷侧,可达131 MPa.Ni-Cr/陶瓷界面残余应力σz较大值出现在Ni-Cr/陶瓷界面近瓷侧的狭小区域内,剪应力τzx的较大值出现在金/瓷界面,向合金和陶瓷两侧递减.采用钛中间层缓解了Ni-Cr/陶瓷界面残余应力,使残余应力向钛中间层转移,残余应力σz较大值出现在钛中间层,剪应力τzx最大值出现在Ni-Cr/Ti界面;随着钛中间层厚度增加,界面残余应力σz增大,剪应力τzx变化不大.     

轧机新型结构导卫板

新型结构导卫板磨损严重的部位用镍铬耐磨合金制度，其余部分用４５号铸钢，采用２次铸造方式使两者牢固地结合成一体。通过实践证明：与整体式镍铬合金导卫板寿命相当，耐磨合金用量减少９０％左右，与组合式导卫板相比简化工序，制造简单，修复使用方便。     

Effect of NaCl vapor on the oxidation of Ni-Cr alloys

Ni-Cr alloys are known for their resistance to high temperature oxidation. The kinetics of scale formation and the nature of the scale in these alloys are affected by NaCl liquid or vapor. There have been a few investigations dealing with the influence of NaCl on long-time exposure. But the nature of reaction at short times can provide information on the initiation of such attack. In this investigation, Ni-Cr alloys with Cr varying from 0 to 25 wt% were exposed to NaCl vapor at 850°C for a few minutes. The surface chemistry of these alloys along with the unattached ones was analyzed by Auger electron spectroscopy. The nature of scale and the distribution of chlorine was found to vary with the Cr content in the alloys, which has a direct bearing on the rate of oxidation of these alloys in NaCl vapor.     

Microstructure and electrical characteristics of Ni-Cr thin films

Microstructure of thin films of different compositions of Ni-Cr alloy, over the range from 40 wt.% to 80 wt.% Ni, deposited on silicon nitride coated GaAs substrates, is investigated under Transmission Electron Microscope (TEM) in as-deposited and annealed conditions. The procedure of wet etching vias through GaAs substrates is used for preparing samples for TEM. Microstructures of as-deposited films of different Ni-Cr alloys are related to the nature of the parent alloy in the binary phase diagram. The microstructural transformations in annealed films of single and two-phase alloy materials are interpreted based on the comparison of TEM micrographs in conjunction with the X-ray diffraction and electron diffraction data. The changes in the electrical characteristics such as resistivity and temperature coefficient of resistance (TCR) of the films in relation to the microstructural transformations are discussed. The effect of superimposing a polyimide layer on the TCR of Ni-Cr films is also discussed.