铁镍合金中硼原子-空位复合体扩散系数的计算

提出一种计算溶质原子-空位复合体扩散系数的方法.该方法通过分析晶界偏聚过程中溶质原子.空位复合体的扩散机制,建立溶质原子-空位复合体变温扩散方程,以实验测定的连续冷却过程偏聚阶段溶质贫化区宽度为已知条件,数值求解溶质原子.空位复合体扩散系数.将此方法应用于含硼1×10-5%(质量分数)Fe-40%Ni-B合金体系,得到硼原子-空位复合体扩散系数为8.0×10-7exp(-1.28/KT)(m2·s-1).     

二氧化锰低温分解动力学研究

采用热重分析仪在5种升温速率下对二氧化锰矿进行热重试验,研究预处理过程中二氧化锰的低温分解行为,并通过物相分析验证热重试验结果及反应推论,应用非模型等转化率法及Popscu法对两步反应动力学求解,得到各自的反应机理函数。结果表明,二氧化锰升温过程发生了两步反应,第一步反应产物为Mn2O3,反应机理为dα/dt=(3.96×109/β)(1-α)e-1.86×105/RT,为一级简单反应,符合Mample单行法则动力学机理特征;第二步产物为Mn3O4,反应机理为dα/dt=(3.28×1024/β)e-2.81×105/RT×(3/2)(1-α)[-ln(1-α)]1/3,符合Avarami-Erofeev方程动力学机理特征。两步反应的反应机理均为随机成核和随后生长。     

GaxIn1—xSb红外材料的MOCVD法生长特性研究

用水平常压 MOCVD 系统生长了 Ga_xIn_(1-x)Sb(0.5相似文献   

焙烧钛渣的反应动力学研究

研究了钠化钛渣加碱焙烧过程的反应动力学、焙烧反应控制步骤,探讨了反应温度、碱渣质量比、钛渣粒度对TiO_2提取率的影响。试验结果表明:在适宜条件下,TiO_2提取率为92%,烧渣TiO_2品位达98.68%;钛渣焙烧优化工艺条件为焙烧温度900℃,碱渣质量比4∶6,钛渣粒度-200目,焙烧时间60min;扩散与化学反应的混合控制作用是影响钛渣焙烧效果的最主要因素,焙烧反应符合收缩未反应核模型,表观活化能为57.39kJ/mol,焙烧动力学方程可描述为1+2(1-x)-3(1-x)~(2/3)=3.532 3exp(-57 390/(RT))·t。     

实际初始WC颗粒尺寸选择的LSW理论分析

超粗硬质合金是一类重要的矿用硬质合金.本文作者通过对WC平均晶粒尺寸为7～8 μm粗晶硬质合金的烧结实验,并用LSW动力学理论分析液相量相对较少的超粗硬质合金(＞5 μm)的晶粒生长机制.分析发现,可以用Co对WC晶粒的覆盖度替代LSW动力学中的原子动力学转移系数.经过修正的LSW动力学方程可以用来指导超粗WC(＞5 μm)实际初始颗粒平均粒度的选择.修正后的LSW动力方程形式为-2ax1--2ax0=0.125(C0γV2m/R)(t/T).     

Effect of Mn on the Magnetostriction and Magnetic Properties in Zr_(0.1)Tb_(0.9)(Fe_(1-x)Mn_x)_2 and Y_(0.1)Tb_(0.9)(Fe_(1-x)Mn_x)_2

Effect of Mn substitution for Fe in cubic Laves Zr_(0.1)Tb_(0.9)(Fe_(1-x)Mn_x)_2 and Y_(0.1)Tb_(0.9)(Fe_(1-x)Mn_x)_2 com-pounds is presented.Similar results in both systems are obtained: The structure and the magnetism of TbFe_2 areboth influenced slightly by a small amount of Y or Zr substitution for Tb;With increasing x value,the latticeconstant increases monotonously;the Curie temperature decreases linearly;while saturation magnetizationincreases linearly.For the small amount of Mn substitution for Fe in both systems,magnetostriction issignificantly larger than that in the pure iron alloys.The largest magnetostriction of|γ_‖-|γ_|=2200×10~(-6)at magnetic field of 2×10~7/4π A/mis obtained for Y_(0.1)Tb_(0.9)(Fe_(0.95)Mn_(0.05)_2.     

钠化焙烧钛渣的酸浸动力学研究

研究了钠化焙烧—酸浸工艺制备高钛渣过程中酸浸动力学、酸浸溶出规律和溶出反应的控制步骤,探讨了反应温度、盐酸浓度、搅拌速度对钛转化率的影响。结果表明,在下述最优工艺条件下,钛转化率达93%,TiO2品位达98.68%:搅拌速度400r/min、液固比10∶1、酸浓度20%、110℃酸浸90min。钛渣焙烧产物酸浸过程受固体产物层的内扩散控制,钛渣酸浸过程符合收缩未反应核模型,表观活化能为11.37kJ/mol,浸出钛渣动力学方程为1+2(1-x)-3(1-x)~(2/3)=0.244exp[-11370/(RT)]t。     

在硅衬底上生长超导薄膜过渡层

本文介绍了在Si(100)衬底上异质外延生长超导薄膜过渡层的方法,研究了过渡层的晶体性质和表面形貌。在Si(100)衬底上外延生长的过渡层依次为Y_2O_3(110)、ZrO_2(100)和Y_2O_3(100)/ZrO_2(100)。最上层生长的即是YBa_2Cu_3O_(7-x)超导膜层,其T_c值达88K。 过渡层用真空蒸镀的方法。首先蒸镀金属钇,并以氧等离子体将其氧化,制成Y_3O_3过渡层。采用ZrO_2晶拉电子束蒸发沉积制成了ZrO_2过渡层。生长器中基础压力为1.33×10~(-5)Pa,生长过程中压力     

焦炭还原焙烧锰矿制备硫酸锰及其机理

以非洲进口锰矿为原料,焦炭为还原剂,进行还原焙烧、硫酸浸出制备硫酸锰溶液。探究焦炭配比、焙烧温度、焙烧时间对锰还原效果的影响,确定最佳工艺参数,并对焙烧反应体系进行热力学分析及对浸出过程进行动力学分析。结果表明,最佳的焙烧条件为：焦炭配比15%、800℃焙烧60 min,锰的还原率达到97.84%。焙烧体系反应都是自发进行的,表观活化能为22.458 6 kJ/mol,且浸出过程受内扩散控制,动力学方程为：1-2x/3-(1-x)^2/3=8.48exp(-22458.6/RT)×t。     

硫化铜精矿加碳酸钙焙烧表观动力学研究

通过DTA和TG结合X 射线衍射分析的方法,将硫化铜精矿加碳酸钙焙烧与硫化铜精矿焙烧的反应机理进行了对比研究。结果表明:加碳酸钙的硫化铜精矿焙烧在673～857K时铜的硫化物被氧化成硫酸盐;在857～1073K时生成的硫酸盐会发生分解。由数据分析可知它的两个阶段都受化学反应控制,其表观活化能和频率因子分别为E1=121.1kJ/mol,E2=182.9kJ/mol,A1=1.155×107s-1,A2=2.115×107s-1,其非等温动力学方程的表达式为:dαRT(1-α)2dT=Aβe-E     

熔炼次数对M17返回料合金成分、组织和性能的影响

实验结果表明,M17铸造高温合金(%:0.16C、8.79Cr、5.79A1、4.93Ti、3.29Mo、15.20Co、0.78V、0.015B、0.073Zr、0.002S、0.001P、0.001 1O、0.001 0N)经25 kg真空感应炉返回重熔后,Si含量随重熔次数的增加而略有增加,合金中主要元素和其它杂质元素S、P、H的含量变化不大,而氧、氮略有增加;合金中初生碳化物由新合金中的草书体逐渐向返回合金块状转变,初生碳化物的遗传性堵塞合金凝固时的补缩通道,使返回料合金的疏松倾向增大,高温塑性下降较大。     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.