Comparison of inward and outward grown Pt modified aluminide diffusion coatings on a Ni based single crystal superalloy

Two commercial Pt modified aluminide coatings (RT22 and MDC150L) on the same single crystal Ni-based superalloy (CMSX-4) were studied by: scanning electron microscopy; transmission electron microscopy; energy dispersive X-ray spectrometry; and gravimetry. The RT22 coating is an inward grown coating (high activity), while MDC150L is produced by outward growth (low activity). Samples were oxidised in still laboratory air at 1050 °C for various times up to 2000 h. It was found that the outward grown coating produced a slower growing oxide that was more spallation resistant. Several possible reasons for this were identified including: coating purity; coating surface topography; and ductile to brittle transition temperature. The microstructural differences between the two coatings in the as-coated condition were investigated and the development of their microstructure during heat treatment was described. A model for coating growth during heat treatment was proposed.     

电位滴定法快速测定洗衣粉中的聚磷酸盐含量

用强酸分解洗衣粉中的聚磷酸盐，以电位滴定法间接测定其中的聚磷酸盐含量。该法简便，快速，结果可靠。     

全球趋向统一的《粉末冶金零件材料规范》

评述了ISO 5 75 5“烧结金属材料—规范”和美国MPIF标准 35的变迁和趋向统一。阐述了“最小强度值”的意义。说明了我国粉末冶金结构零件材料标准的现状     

新型海洋涂料技术

本文综述了符合时代要求的海洋涂料新技术及其发展趋势。     

45钢表面超音速电弧喷涂Ti-Al涂层的组织与性能研究

采用自行开发研制的超音速电弧喷设备，在45钢表面制成了钛铝合金复合涂层。并利用金相显微镜、X射线衍射仪、扫描电镜、电子探针，对涂层的成分、相结构、显微组织及其结合强度、显微硬度进行了研究。结果表明，利用超音速电弧喷涂设备，可以在45钢表面形成 度高、孔隙率低，结合强度较好和硬度高的Ti-Al合金涂层。     

Influence of Edible Films upon the Moisture Loss and Microstructure of Dietetic Sucrose-Free Sponge Cakes during Storage

The kinetics of changes in the bound water content in dietetic sucrose-free sponge cakes (DC) during storage was investigated. The effect of edible films of polymyxan, pectin, xanthan, and carboxymethylcellulose upon this kinetics was also investigated. The quantitative changes in both states of water (slightly bound water and strongly bound water) were registered by combined dynamic analysis (thermogravimetry analysis, TGA, and differential thermal analysis, DTA). The moisture changes in DC crumb were analyzed by drying out to constant mass. The rate constants were determined according the equation q = q_oe^-kt. The values of rate constants 'k', in day^-1, concerning the different edible films were as follows: for crumb moisture is (8.00 ≤ k ≤ 12.47) × 10^-3, for bound water is (3.07 ≤ k_w ≤ 6.26) × 10^-2, for slightly bound water is (4.22 ≤ k₁ ≤ 8.49) × 10^-2 and for strongly bound water is (2.02 ≤ k₂ ≤ 5.62) × 10^-2 as compared to 18.53 × 10^-3, 7.16 × 10^-2, 9.04 × 10^-2, and 5.36 × 10^-2 in the uncovered DC, respectively. The best water-retaining effect in respect to crumb moisture during storage was ascertained in the use of polymyxan and xanthan films. The lowest rate constant values for bound water and its two states were measured for DC covered with pectin. The relation between the kinetics of both bound water states during storage and ageing of the crumb of DC covered with different edible films and the crumb microstructure was represented. By means of scanning electron microscope was read the smallest change in crumb microstructure of pectin-covered DC on the sixth day of storage.     

电沉积法制备铜分散电极

研究了电沉积制备铜分散电极的方法,通过对阴极极化曲线的测试,考察了电流密度及不同冲击电流方式对铜粉粒度的影响。结果表明:适当的电流密度、合适的分散剂、间歇式的电流是得到较细铜粉的条件。同时对铜分散电极的电化学性质进行初步测试,结果表明铜粉细化以后,铜分散差电池的电动势值有所上升。     

Corrosion Inhibition Mechanism with Spilt Cell Technique of Rare Earth Metal on LC4 Al Alloy

A new method of studying the corrosion inhibition mechanism of rare earth metal(REM) on LC4 Al alloy with the spilt cell technique was studied. The principle and experimental method of the spilt cell technique were analyzed. By measuring the change of net-electric current between the two electrodes caused by the change of the amount of oxygen in the solution and the addition of CeCl₃, the influence of corrosive performance of CeCl₃ on LC4 super-power aluminum alloy in the 0.1 mol·L⁻¹ NaCl solution was investigated. Meanwhile, the conditional changes of pH values, CeCl₃ solution, additire and time of performance were also studied. Finally, the features of electrode surface were revealed by using SEM and X-ray energy-dispersive spectrometry (EDS). By combining these with other electric chemical techniques, such as potential-time curve, polarization curve et al.