材料期刊网

Morphological Changes During Annealing of Electrodeposited Ni-Cr Coating on Steel and Their Effect on Corrosion in 3% of NaCl Solution

Manpreet Singh Marwah , Vajjala Srinivas , Ajoy Kumar Pandey , Shyam Ranjan Kumar4 , Koushik Biswas , Joydeep Maity5

钢铁研究学报(英文版)

Steel containing carbon of 02% was coated with Ni and Cr through electrodeposition, and subsequently annealed at 400 and 600 ℃ for 5 min, 30 min, 1 h and 2 h. During annealing at 400 ℃, the formation and growth of oxides occurred in the form of petals along with voids, cracks and porosities. However, at 600 ℃, the nucleation and growth of chromium oxide whiskers produced a surface almost free from crack, porosity and void for 1 h and 2 h of holding. In accordance with the surface morphology, the bare steel, as-deposited steel, all specimens deposited and annealed at 400 ℃, and specimens deposited and annealed at 600 ℃ for 5 and 30 min exhibited continuous corrosion in 3% of NaCl solution. However, the specimens deposited and annealed at 600 ℃ for 1 and 2 h exhibited an improved corrosion resistance in 3% of NaCl solution with high pitting potential due to presence of a dense passive oxide film almost free from voids at the surface.

关键词: steel , electrodeposition , annealing , corrosion resistance

TC4盒形钣金零件气压成形工艺的研究

袁清华 , 张文明 , 黄重国 , 任学平

稀有金属 doi:10.3969/j.issn.0258-7076.2009.04.005

采用普通工业TC4板料,在MTS高温拉伸试验系统上进行了不同变形条件的恒速拉伸试验,研究材料的高温变形行为.分析了5类通用高温本构关系对该材料真实应力应变曲线的拟合情况.最终,采用经典的Kumar模型建立了TC4的高温本构关系.利用MARC分析TC4机身盒形零件的气压成形过程,依据正交试验原理确定FEA仿真方案,并对成形模具进行了设计.以壁厚标准差为评价指标,采用极差分析法确定各因素对指标的影响程度和最佳工艺参数,并通过气压成形试验获得满足质量要求的零件.

关键词: TC4(Ti-6Al-4V) , 本构关系 , 气压成形 , 有限元分析

Systematic Study of the Simple Predictive Approaches for Thermodynamic and Transport Properties of Multicomponent Solutions

Industrial & Engineering Chemistry Research

The densities, viscosities, and conductivities were measured for the ternary solution NaCl + urea + H(2)O, the quintuple solution NaC1 Na(2)SO(4) KCl K(2)SO(4) + H(2)O, and their binary subsystems at 298.15 K. The results together with the densities, viscosities, and conductivities of multicomponent solutions reported in the literature were used to study the predictability of the Young's rule for density and conductivity, the rule of Patwardhan and Kumar for density, Flu's equation for the viscosity of mixed electrolyte solutions based on the Eyring's absolute rate theory and the rule of Patwardhan and Kumar, and the semiideal solution theory for thermodynamic and transport properties. The results show that all the tested equations can provide comparable and accurate predictions for the densities of multicomponent electrolyte solutions. The semiideal solution theory is applicable to the aqueous solutions of electrolytes and nonelectrolytes, and its predictions for the densities of the examined solutions are in nice agreement with the experimental results. The simple equation based on Eyring's absolute rate theory and the rule of Patwardhan and Kumar and the semiideal solution theory can provide nice predictions for the viscosity of the tested electrolyte solutions. The predictions for the viscosity of the ternary solution NaCl + urea + H(2)O by the semiideal solution theory are also in accordance with the measured viscosities. The semiideal solution theory can provide better predictions for the conductivities of the tested electrolyte solutions than the extended Young's rule, and their predictions are both in good agreement with the experimental results. The advantages of the semiideal solution theory are briefly discussed and reviewed.

关键词: mixed-electrolyte-solutions;linear isopiestic relation;absolute rate;theory;aqueous-solutions;298.15 k;activity-coefficients;sodium-chloride;potassium-chloride;ternary subsystems;unified;approach

NH4GdF4的合成机理研究

姜银举 , 张小琴 , 郭海涛 , 王佐成

稀土 doi:10.3969/j.issn.1004-0277.2008.06.021

利用差热-热重分析方法,研究了Gd2O3和NH4HF2反应中间产物NH4GdF4的合成机理.结果表明,NH4GdF4是在NH4HF2熔化后与Gd2O3通过固-液相反应直接合成的;Gd2O3和NH4HF2反应的另一种中间产物为NH4F,NH4F在稍高的温度下热分解为NH3和HF;NH4F与GdF3不能合成NH4GdF4 ;GdOF也可以与NH4HF2反应合成NH4GdF4,但GdOF不是Gd2O3和NH4HF2反应的中间产物.分析了Gd2O3和NH4HF2反应不能完全合成NH4GdF4的原因.

关键词: NH4GdF4 , 合成 , 机理

TiO2对制备Al4SiC4-Al4O4C复合材料的作用

邓承继 , 匡健磊 , 祝洪喜 , 白晨

耐火材料 doi:10.3969/j.issn.1001-1935.2009.04.002

的TiO2在1 300 ℃前全部反应转变为TiC,生成的TiC在1 300～1 700 ℃稳定存在;Tio2加入量对材料物相组成没有明显影响,但TiO2加入量超过3%时,Al4SiC4和Al4O4C的生成温度将由1 500℃提升至1 600℃;随着材料中Ti4+浓度增加,Ti4+更容易与Al4SiC4形成有限置换固溶体而导致晶格缺陷,促使Al4SiC4在1 700℃分解,形成更多的Al4O4C短纤维,同时使试样表面生成片状Al2O3层.

关键词: Al4SiC4-Al4O4C复合耐火材料 , TiO2 , 固溶 , 显微结构

10Cr4Ni4Mo4V钢和Cr4Mo4V钢的特性与断裂行为

叶健熠 , 王杰君 , 谷臣清

材料开发与应用 doi:10.3969/j.issn.1003-1545.1999.03.004

对10Cr4Ni4Mo4V钢和Cr4Mo4V钢的特性与断裂行为进行了试验研究.结果表明,10Cr4Ni4Mo4V钢经微氮渗碳热处理后,其表面硬度、残余应力、断裂韧性及裂纹扩展速率均优于Cr4Mo4V钢的.

关键词: 钢 , 特性 , 断裂韧性 , 裂纹扩展速率

Al4SiC4的性能、制备和应用

邓承继 , 辜孔良 , 祝洪喜 , 谢大勇 , 李涛

耐火材料 doi:10.3969/j.issn.1001-1935.2008.05.017

介绍了一种待研发的新型三元碳化物Al4SiC4(碳硅化铝)的组成和基本性能,并重点讨论了Al4SiC4的各种合成和制备方法,如固相反应烧结法、高温自蔓延法等的原理及效果.首先讨论了Al4SiC4材料的基本性能、抗氧化性能和抗水化性能,比较了Al4SiC4和其他材料之间的性能差异,并介绍了Al4SiC4的应用范围;最后对Al4SiC4材料的合成方法和性能进行了总结,同时指出了碳硅化铝材料作为新型耐火材料的研究和使用的进一步研究方向.

关键词: Al4SiC4 , 制备 , 性能 , 应用

4,4'-二(4-氯甲酰苯氧基)二苯砜的合成

黄振钟 , 霍毅 , 罗秋燕 , 刘卓 , 盛寿日

应用化学 doi:10.3969/j.issn.1000-0518.2007.08.013

以DMF作溶剂,在四丁基氟化铵 (TBAF)存在下,对甲基苯基三甲硅基醚(1)和4,4'-二氯二苯砜(2)于100 ℃反应1 h,合成了4,4'-二(4-甲基苯氧基)二苯砜(3),产率为92%;加入催化量的N-溴代丁二酰亚胺(NBS)并在光照条件下,与氧气反应得到中间体-4,4'-二(4-羧基苯氧基)二苯砜(4),其产率达90%;将化合物4与二氯亚砜反应合成目标产物4,4'-二(4-氯甲酰基苯氧基)二苯砜(5),总收率为74.5%(以对甲基苯基三甲硅基醚为基准计算).

关键词: 对甲基苯基三甲硅基醚 , 二氯二苯砜 , 二(氯甲酰基苯氧基)二苯砜 , 合成

固相反应合成Al4SiC4材料

邓承继 , 李涛 , 白晨 , 顾华志

耐火材料 doi:10.3969/j.issn.1001-1935.2005.04.002

采用粒度14μm的磨料级碳化硅,粒度10 μm的工业级金属铝粉和粒度5 μm的工业级炭黑粉为原料,按SiC:Al:C质量比为22:59:19配料制成试样,在氩气保护下,分别在1200℃8 h、1600℃2 h和1650℃2 h烧成,研究了通过固相反应合成Al4SiC4材料的条件和动力学过程.通过X射线衍射仪进行物相分析,扫描电子显微镜和透射电子显微镜的形貌分析以及能谱分析确定成分.结果表明:反应体系在1200℃以下,铝和炭黑反应首先生成中间相Al4C3;从1200℃开始通过SiC+Al4C3=Al4SiC4固相反应生成Al4SiC4;当合成温度达到1650℃时,获得Al4SiC4材料;制备的Al4SiC4材料的颗粒均匀,尺寸在几百纳米到几微米之间.

关键词: Al4SiC4 , 固相反应合成 , 机理

4-羟基-4′-氰基联苯的合成

杨雪艳 , Aliibrah Landi , 吴范宏

液晶与显示 doi:10.3969/j.issn.1007-2780.2002.06.006

以4-羟基联苯为原料,经酰化、氨解、脱水三步反应合成了液晶材料重要中间体4-羟基-4'-氰基联苯,总收率达51.8%.其结构经核磁共振、质谱、红外光谱等确证,HPLC含量在99%以上.

关键词: 液晶中间体 , 合成 , 4-羟基-4'-氰基联苯