镁铝质陶瓷涂层制备工艺与性能研究

本文采用料浆法在1Cr18Ni9基体上制备陶瓷涂层,并进行性能进行测试。实验表明金属基陶瓷涂层的耐酸性能提高了23%,耐碱性能提高了8%。

格子方差法在镁铝质预制件混合均匀性检测中的应用

镁铝质预制件的混合均匀性对其物理性能和使用寿命有着显著的影响。本文依据胡力群等提出的格子方差法对镁铝质预制件的混合均匀性进行应用评价。利用python对图像降噪处理后,采用第三方库opencv中的Canny算法和高斯滤波对镁铝质预制件切割断面进行颗粒边缘识别和分布离散系数的计算。指出了该理论在长宽比例较大的镁铝质预制件颗粒分布离散系数计算中存在的不足及相应的修正方法,通过对同一图像选取能覆盖所有面积的方案多次计算颗粒分布离散系数并取平均值,以减少选取区域对结果的影响程度。

一种无水泥镁铝质喷射料的研制与应用

为开发适合水泥窑各温度带使用的高性能喷射料,以电熔镁砂骨料、复合尖晶石微粉、刚玉微粉等为原料制备出镁铝质湿式喷射料。研究了减水剂类型、减水剂加入量、骨料颗粒形状对镁铝质喷射料加水量及性能的影响。结果表明:1)聚羧酸盐高效减水剂减水效果最佳,其最佳加入量为0.28%(w),加水量小于5%(w);2)减水剂相同的条件下,圆形或椭圆形颗粒加水量较少;3)按最佳配比3#-O制得的镁铝质喷射料,性能优异,可与石灰、水泥窑用烧成镁铝尖晶石砖相比拟,能够满足水泥窑过渡带和石灰窑高温带对材料性能的要求,喷射附着率达到95%以上,基本上没有反弹,没有粉尘飞扬。

镁铝质耐火材料在中频电炉上的应用

以镁铝质耐火材料为原料，用磷酸盐为结合剂的炉衬材料，用于半吨中频感应电炉上，在冶炼温度大于１６５０℃的状况下，一次性使用寿命远远高于在相同工作条件下的石英质酸性炉衬材料，可大大提高中频炉的生产效率。

镁铝质、铝镁质、镁碳质耐火材料中MgO的快速检测

镁铝质、铝镁质、镁碳质耐火材料采用HCl直接分解样 ,用EDTA标准溶液直接滴定 ,以消耗EDTA标准溶液的量求得MgO的百分含量。此方法简便、稳定、快速。

滑板磨床粉对镁铝质浇注料性能的影响

为了研究滑板磨床粉对镁铝质浇注料性能的影响,以95中档镁砂、88矾土和硅灰为主要原料制备镁铝质浇注料。研究了滑板磨床粉加入量为2%、4%、6%对镁铝质浇注料的体积密度、显气孔率、常温抗折强度、抗渣渗透性和抗渣侵蚀性能的影响。综合分析得出,当滑板磨床粉加入量为2%时,使用效果最佳。

α-Al_2O_3微粉对镁质浇注料性能的影响

研究α-Al2O3微粉加入量对钢包渣线用镁铝质浇注料线变化率、显气孔率、耐压强度和抗渣性能的影响,借助EDAX分析,探讨了浇注料的渣蚀机理。结果表明,随着α-Al2O3质量分数的增加,经1000℃×3h热处理后,浇注料的线变化率逐渐增大,显气孔率增加,耐压强度提高;经1600℃×3h热处理后,浇注料的线变化率逐渐增加,显气孔率稍有减小,耐压强度逐渐降低,但当α-Al2O3质量分数大于10%后,浇注料的耐压强度增加;随着α-Al2O3质量分数的增加,浇注料渗透指数逐渐减小,但侵蚀指数明显增大。镁铝质浇注料的性能变化主要与材料的组成和显微结构相关。

纳米技术在镁质耐火材料中应用的研究进展

利用纳米技术制备复相镁质耐火材料,不仅可以缓解高温工业对高性能镁质材料的需求,而且又能实现镁质耐火材料的轻质化和多功能化,进而达到提高产品附加值的目的.因此,利用纳米技术制备复相镁质耐火材料具有较高的研究意义.从镁质耐火材料损毁机制的角度,综述了近年来国内外纳米技术在低碳镁碳质、镁钙质、镁铝质耐火材料中的研究现状和进展,并且分析了纳米技术在镁质耐火材料中的作用机理,最后指出了纳米技术在镁质耐火材料中应用所面临的挑战和发展方向.

炼铜用耐火材料研究进展

炼铜工艺的稳定顺行离不开耐火材料的有力支撑。本文概述了炼铜工艺及其所需的耐火材料,说明了炼铜炉不同部位耐火材料的主要类型、性能特点和制备工艺,重点介绍了炼铜过程中常用镁铬质耐火材料、镁铝质耐火材料和其他新型耐火材料。随着材料科学的不断发展和环保要求的不断提高,研究者针对镁铬质耐火材料的性能优化和带来的环境问题、镁铝质耐火材料的材料特性和渣蚀问题,以及其他新型耐火材料的性能调控问题等开展了系统研究,为炼铜工艺技术的不断优化提供了有力支持。尽管炼铜用耐火材料在服役性能方面的研究已取得显著进展,但仍面临应用成本高、对环境不够友好、新材料制备与开发困难等问题。基于此,提出下一步耐火材料性能提升和节能环保的研究方向。

基质组成对MgO-Al_2O_3质浇注料性能的影响

研究基质组成对MgO Al2O3质浇注料热震稳定性和抗渣性能的影响。结果表明,随着α Al2O3含量的增加,MgO Al2O3质浇注料1600℃×3h抗折强度逐渐降低,α Al2O3质量分数大于15%后抗折强度明显增大;α Al2O3加入量为10%～15%时浇注料具有最佳的热震稳定性;随着α Al2O3含量的增加,浇注料渗透指数明显减小,侵蚀指数逐渐增大。MgO Al2O3质浇注料的性能主要与基质的组成和显微结构相关。

Electrochemical corrosion behaviour of stir zone of friction stir welded dissimilar joints of AA6061 aluminium-AZ31B magnesium alloys

Joining of dissimilar metals will offer many advantages in transportation sectors such as fuel consumption,weightreduction and emission reduction.However,joining of aluminium(Al)alloys with magnesium(Mg)alloys by fusion welding processis very complicated.Friction stir welding(FSW)is a feasible method to join these two dissimilar alloys.Mixing these two metalstogether in stir zone(SZ)leads to poor corrosion resistance.In this investigation,an attempt has been made to understand thecorrosion resistance of SZ of FSWed dissimilar joints of AA6061Al alloy and AZ31B Mg alloy.Potentiodynamic polarization testwas conducted by varying chloride ion concentration,pH value of the NaCl solution and exposure time.The corroded surfaces wereanalyzed using optical microscopy,scanning electron microscopy and XRD techniques.Of these three factors investigated,exposuretime is found to be the most significant factor to influence the corrosion behaviour of SZ of friction stir welded dissimilar joints ofAl/Mg alloys.

Assessment of solidification characteristics of carbon-inoculated Mg-3%Al melt by thermal analysis

The Mg-3%Al melt was inoculated by carbon with different holding time.The effect of holding time on grain refining efficiency was evaluated.The solidification characteristics of the carbon-inoculated Mg-3%Al melt with different holding time were assessed by computer-aided cooling curve analysis.The results showed that Mg-3%Al alloy could be effectively refined by carbon inoculation.Slight fading phenomenon occurred with increasing the holding time to 60 min.Carbon inoculation could significantly influence the shape of cooling curves of Mg-3%Al melt.The nucleation starting and minimum temperatures increased.The recalescence undercooling and duration decreased to almost zero after carbon inoculation.The grain refining efficiency of carbon inoculation could be assessed by the shape of the cooling curve and solidification characteristic parameters including nucleation starting and minimum temperatures,recalescence undercooling and duration.

5A06-O aluminium−magnesium alloy sheet warm hydroforming and optimization of process parameters

The uniaxial tensile test of the 5A06-O aluminium−magnesium(Al−Mg)alloy sheet was performed in the temperature range of 20−300℃ to obtain the true stress−true strain curves at different temperatures and strain rates.The constitutive model of 5A06-O Al−Mg alloy sheet with the temperature range from 150 to 300℃ was established.Based on the test results,a unique finite element simulation platform for warm hydroforming of 5A06-O Al−Mg alloy was set up using the general finite element software MSC.Marc to simulate warm hydroforming of classic specimen,and a coupled thermo-mechanical finite element model for warm hydroforming of cylindrical cup was built up.Combined with the experiment,the influence of the temperature field distribution and loading conditions on the sheet formability was studied.The results show that the non-isothermal temperature distribution conditions can significantly improve the forming performance of the material.As the temperature increases,the impact of the punching speed on the forming becomes particularly obvious;the optimal values of the fluid pressure and blank holder force required for forming are reduced.

Effect of Surface Treatment on Bonding Strength of Aluminum-Magnesium Hot-Rolled Composite Plate

The effect of different surface treatments on the bonding strength of composite plates was investigated under the conditions of 400℃ and reduction ratio of 45%.Results show that the wire brush grinding treatment can only eliminate the oxide film on the plate surface,but it can hardly produce a hard layer on the plate surface.The bonding effect depends on the element diffusion promoted by the close contact between the metals on both sides of the interface.After anodic oxidation,there is a hard layer on the metal surface,and the hard layer broken during the rolling process forms a mechanical occlusion at the bonding interface.However,the hard layer cannot form an effective combination with the metal at the interface,and the bonding can only occur in the fresh metal bonding area at the crack of the hard layer.The acid-alkali washing treatment can completely remove the hard layer on the surface of both alloys without increasing the surface roughness of the plate,and the metal on both sides of the interface is more closely bonded during the rolling process.The optimal bonding strength can be obtained by surface treatment of acid-alkali washing for the aluminum-magnesium hot-rolled bonding.