焦炭催化CO-NO反应的动力学实验研究北大核心CSCD

从高炉风口喷吹烧结烟气是一种有别于传统烟气脱硝工艺的新思路。为探究烧结烟气喷入风口后,焦炭催化CO-NO还原反应的动力学过程,实验以CO、NO气体为原料,以焦炭为催化剂,将不同流量配比的CO和NO混合气体在炉温为850~975℃时通入炉内,在出口处测量CO和NO反应后体积分数。实验结果表明,焦炭对CO还原NO反应有明显的催化作用;反应温度不变,CO和NO的流量比增大时,NO的还原率会增大;CO和NO的流量比不变,温度增大时,NO的还原率也会增大;炉温850、900、925、950、975℃时,反应速率常数分别为0.56、0.88、0.78、1.28、1.38 m^(3)/(mol·s),通过拟合动力学参数得到反应的活化能E;为84.1 kJ/mol。     

Influence of alloy ingredients on mechanical properties of ternary boride hard alloy clad materials

Using Mo, B-Fe alloy and Fe powders as raw materials, and adding C, Cr and Ni ingredients, respectively, or C, Cr and Ni mixed powders, ternary boride hard alloy clad materials was prepared on Q235 steel substrate by means of in-situ reaction and vacuum liquid phase sintering technology. The influence of alloy ingredients on the mechanical properties of ternary boride hard alloy clad materials was investigated. The results indicate that a mixture of 0.8% C, 5% Cr and 2% Ni ingredients gives a ternary boride hard alloy clad material with optimal mechanical properties, such as high transverse rupture strength, high hardness and good wear resistance.     

Intelligent optimal control for lead-zinc sintering process state

The intelligent integrated predictive model of synthetical permeability was established using the fuzzy classifier to combine the time sequence predictive model with the craftwork parameter predictive model. Then, the estimation model of bum-through point（BTP） based on pipe stress point（PSP） method and the predictive model of BTP were proposed. The optimal control of permeability and heat states was implemented by using the fuzzy expert controller with self-studying mechanism. The application of the intelligent control technique suppresses 17% of the fluctuation of synthetical permeability and 12% of the fluctuation of BTP, stabilizes the output and quality of sinter and settles the basis for the optimization of output and quality of sintering process.     

碳化硼材料的性能、制备与应用

B4C具有高熔点、高硬度、低密度等优良性能,并具有良好的中子吸收能力和抗化学侵蚀能力,因而广泛应用于耐火材料、工程陶瓷、核工业、宇航等领域。本文对B4C的结构、性能、粉末制备方法、B4C陶瓷的烧结技术以及应用等方面作了综述。     

Electric and mechanical performances of Bi0.5Sb1.5Te3 prepared by spark plasma sintering

Thermoelectric (TE) materials are a kind of functional materials which can be used to convert directly heat energy to electricity or reversely.The thermoelectric effects hold great potential for application in power generation and refrigeration.Bi2Te3 and its alloys are well known as best TE materials currently available near room temperature.This paper studies respectively the effects of spark plasma sintering (SPS) on electric performance of Bi0.5Sb1.5Te3 thermoelectric materials that are prepared through vacuum melting and ball milling.Through X-ray Diffraction and cold field emission scanning electric microscope s4800, the phase constituent and microstructure of the TE materials samples were analyzed.Electric conductivity and power factor can be improved with the rise of Spark Plasma Sintering temperature (from 300 to 500 ℃) and pressure(from 30 to 60 MPa), and the density and mechanical strength of Bi0.5Sb1.5Te3 thermoelectric material increase, too.     

高铁三水铝石型铝土矿的烧结特性

以Al2O3含量为26.35%,总Fe含量为31.22%,铝硅比为3.17的某高铁三水铝石型铝土矿为原料,研究了碱度、焦粉用量、混合料水分等对烧结矿质量指标的影响。结果表明:烧结矿碱度增加时,其转鼓强度和成品率下降,烧结矿自粉化程度加重;焦粉用量增加时,烧结矿转鼓强度和成品率提高;当混合料水分为9.0%、焦粉用量为8.0%、烧结矿碱度为4时,烧结矿转鼓强度为69.1%,成品率为81.2%,垂直烧结速度为30 mm/min,利用系数为1.2 t/(h.m2);烧结矿碱度为4时,样品存放2天粉化率为5%,烧结矿平均粒度由22.2 mm减小到21.9 mm,延长存放时间,烧结矿自粉化率增大,平均粒度显著减小。该烧结矿的冶金性能能基本满足高炉冶炼的要求。     

复合助剂对低温常压烧结AIN性能的影响

研究了Y2O3,LiO2,CaO烧结助剂对AlN陶瓷常压烧结致密度和性能的影响。结果发现,同时添加Y2O3,LiO2,CaO作为助剂,在1600℃低温烧结就能获得具有高致密度、较小的晶粒尺寸(1μm~4μm)、较高的抗弯强度(331MPa)、断裂韧性(3.8MPa·m1/2)及导热率(118W·m-1·K-1)的AlN陶瓷。     

稀土Y对纳米粉90W-Ni-Fe合金性能和微观结构的影响

采用SEM和金相仪器对添加不同Y量的纳米粉90W-7Ni-3Fe合金试样断口进行形貌观察和W晶粒测试：并对烧结态试样的相对密度、抗拉强度、延伸率等性能进行测定与分析。结果表明：当Y量在0．2％～0．6％（质量百分数，下同）时，试样相对密度为99.2％～99．6％，抗拉强度为1000MPa-1100MPa，延伸率为16％-19．5％：添加0．4％Y后，W晶粒从原来的20μm～25μm减小到12μm，W晶粒形状由不加稀土时的球形变为近球形或多边形。添加0．4％Y后，在界面上形成了W13．07Ni2.96Fe1.52Y23．65Ox（摩尔数比）的中间相，其阻止了W原子在粘结相中的扩散，阻止了W晶粒长大，细化了W晶粒，提高了合金的性能。     

高浓度熟料溶出的工艺研究

优化烧结法生产 ,提高产量、节约能耗是氧化铝生产急需解决的问题之一。实现高浓度溶出可以提高精液浓度 ,减少湿法系统物料流量 ,达到提高产能、增加产量、降低成品成本的目的。本文通过对国内外高浓度熟料溶出发展情况和烧结法影响高浓度溶出的因素进行分析研究 ,提出了提高熟料A/S的必要性 ;指出了适合我国条件的熟料A/S大小和生料配方 ;分析了温度和αk 对溶出和分离的影响机理和规律 ;提出了适合高浓度溶出的溶出条件和浓度大小。对生产有一定的指导意义。     

ZrB2-SiC基超高温陶瓷（UHTCs）的反应烧结及SHS粉体制备

用普通反应热压方法（RHP）和反应放电等离子体方法（R-SPS）原位反应制备了ZrB2-SiC，ZrB2-SiC—ZrC，ZrB2-SiC-ZrN，以及ZrB2-SiC-AIN4种复合材料。从密度，物相以及显微结构等方面比较了两种烧结方式之间的差别，对于升温速度较慢的普通热压方法，反应分步进行，显微结构不均匀；对于升温速度快的放电等离子体烧结，原料间的自蔓延反应被点着，反应速度快，显微结构均匀。同时以红外灯的热量为点火源，引发了Zr，Si及B4C间在空气气氛下的自蔓延反应，制备了较纯及粒径约为1μm的活性粉体。