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刘新佳 《理化检验(物理分册)》1998,34(7):37-37
在金相分析中,有时为研究某些试样中的第二相或疏松、微裂纹等微观缺陷及裂纹的扩展情况等立体形态或分布特征时,需要测定其厚度方向的尺寸,即需要测出试佯磨抛去除层的厚度,此时,由于用测微仪只能测出试样表面的相对平整程度,对此就显得无能为力了.为此,我们试验开发出了显微硬度计的另一种用途——金相试样磨抛去除层厚度的无基准精确测量.现介绍如下.1 试验方法试样经400目以上金相砂纸精磨后,用压头为136°金刚石角锥的显微硬度计在试样磨面上打一显微压痕,压痕放大后如下图所示.由于压痕形状是与金刚石压头一致的两相对面间夹角α=136°的正四方锥形,它在试样磨面的投影为正方形□ABCD,抛光后则成为□abcd.设该两正方形的边长和对角线长分别为l_0、l_1和d_0、d_1,则它们之间的关系为: 相似文献
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氰化镀金槽液中游离氰化物的测定 总被引:2,自引:0,他引:2
在氨性溶液条件下,采用标准镍溶液滴定法对氰化镀金溶液中的游离氰化物进行测定,对测定原理和指示剂的变色机理进行了阐述。实验结果表明,应用该法测定游离氰化物浓度,操作快速简便,准确高度,易于掌握。 相似文献
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多晶硅生产的还原炉壁体热反射率的高低对电能消耗有很大的影响,过去,少有相关的研究报道。使用亚硫酸盐体系对还原炉内壁电镀金,研究了镀金电流密度、镀覆时间等对镀金层光亮度、热反射率的影响;探讨了镀液中配位剂亚硫酸钾浓度对镀层显微硬度、沉积速率及阴极电流效率的影响。结果表明:电流密度为0.4A/dm2,镀覆时间为10 min时镀金层外观质量最好,亚硫酸钾浓度为100 g/L时镀金层的显微硬度、阴极电流效率和沉积速率达到最大值;镀金层的光亮度与电流密度和镀覆时间有很大关系;镀金层的热反射率比不锈钢基体的高,光亮镀层的热反射率比半光亮镀层的高;镀液中亚硫酸钾含量的变化使得镀金层的显微硬度和沉积速率发生了改变。 相似文献
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《超级VCD技术规范》终于在去年由信息产业部颁布,就此超级VCD开始正式上市。超级VCD与DVD之争的大幕也就此拉开了。SVCD结合了DVD与VCD的优点,具有以下的性能特点和使用功能:1高品质的影音播放效果。SVCD的图像分辨格式为2/3D1,像... 相似文献
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本文对冷库围护结构防结露厚度、经济厚度进行研究 ,并对我国三地区内新型保温材料作了计算和分析 ,得出了冷库不同情况下最小保冷厚度的结论。 相似文献
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Interplay of Solvent Additive Concentration and Active Layer Thickness on the Performance of Small Molecule Solar Cells 下载免费PDF全文
John A. Love Samuel D. Collins Ikuhiro Nagao Subhrangsu Mukherjee Harald Ade Guillermo C. Bazan Thuc‐Quyen Nguyen 《Advanced materials (Deerfield Beach, Fla.)》2014,26(43):7308-7316
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利用双液铸造液膜连接工艺制备大平面的低碳钢/高铬铸铁耐磨板。采用SEM,EDS对复合层进行组织观察及成分分析。结果表明:不同厚度的复合板从低碳钢侧至高铬铸铁侧可以分为低碳钢→珠光体过渡层→复合层→高铬铸铁过渡层,双金属复合层完全实现了冶金结合。通过对复合层区域进行显微硬度分析,从低碳钢至高铬铸铁侧的显微硬度在345~1260HV范围梯度分布。复合层的显微组织主要为γ-Fe+粒状碳化物。高铬铸铁过渡层奥氏体组织呈现垂直复合层方向的树枝状生长,并随着耐磨板厚度的增加,奥氏体生长的方向性逐渐消失。根据低碳钢的温度变化初步建立了相关的温度场数学模型。 相似文献
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在Na5P3O10-KOH-Na2EDTA电解液中, 以石墨烯为添加剂, 在恒压模式下对ZrH1.8表面进行微弧氧化处理。采用涂层划痕仪测试陶瓷层与基体的结合力, 通过真空脱氢实验来评价陶瓷层的阻氢性能。电解液中添加石墨烯后, ZrH1.8表面微弧氧化陶瓷层均由内层致密层和外层疏松层构成, XRD图谱显示, 所制陶瓷层主要由M-ZrO2和T-ZrO2相组成。随着石墨烯浓度的增加, 陶瓷层的氢渗透降低因子(Permeation Reduction Factor, PRF)呈先增大后减小的趋势。当石墨烯浓度为0.10 g/L时, 陶瓷层的厚度约为66.5 μm, 表面孔洞和裂纹较少, 陶瓷层较致密, PRF值为13.2, 阻氢性能较好。 相似文献
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《IEEE transactions on instrumentation and measurement》1979,28(1):26-31
A continuous-wave phase comparison technique which provides at least an order of magnitude improvement in accuracy over modulated carrier systems which operate in the same spectrum is described in this paper for the remote determination of the thickness of layered targets consisting of a known number of dielectric layers, each of a known maximum thickness. This system uses rationally related frequencies such as the fundamental and its harmonics to establish a multifrequency coherence relationship whereby a phase reference between frequencies can be conserved and information extracted from just the received and not the transmitted signals. Consequently, Doppler effects due to motion between the target layer and the apparatus, as well as local oscillator stability and drift limitations are avoided. Thus this system can measure the parameters of remote layered targets by interferometric techniques without the distance being a constraint. 相似文献
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P. C. Pullammanappallil R. S. Iyer B. R. Stanmore Xiao Yang He 《Particulate Science and Technology》2013,31(2):179-187
Abstract The leaching of elements from the surface of charged fly ash particles is known to be an unsteady process. The mass transfer resistance provided by the diffuse double layer has been quantified as one of the reasons for this delayed leaching. In this work, a model based on mass transfer principles for predicting the concentration of calcium hydroxide in the diffuse double layer is presented. The significant difference between predicted calcium hydroxide concentration and the experimentally measured is explained. 相似文献
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P. C. Pullammanappallil R. S. Iyer B. R. Stanmore Xiao Yang He 《Particulate Science and Technology》2005,23(2):179-187
The leaching of elements from the surface of charged fly ash particles is known to be an unsteady process. The mass transfer resistance provided by the diffuse double layer has been quantified as one of the reasons for this delayed leaching. In this work, a model based on mass transfer principles for predicting the concentration of calcium hydroxide in the diffuse double layer is presented. The significant difference between predicted calcium hydroxide concentration and the experimentally measured is explained. 相似文献