低温烧结氧化铝陶瓷的动力学研究

用CaO-MgO-SiO2玻璃(CMS-G)和TiO2为烧结助剂,在1450℃下实现了氧化铝陶瓷的致密烧结.探讨了CMS-G和TiO2质量百分含量对氧化铝陶瓷烧结性能、显微结构以及其烧结动力学的影响.结果表明:CMS-G和TiO2可有效促进氧化铝陶瓷的致密化,当CMS-G含量为3%、TiO2含量为1%时,氧化铝陶瓷的相对密度达到98.25%;液相烧结激活能为113.4kJ/mol,表明扩散控制了烧结过程.     

氧化铝陶瓷的形状记忆效应机理的探讨

采用粒径为0.5微米的自制氧化铝超细粉,采用低温快烧工艺在CaO—MgO—Al2O3—SiO2体系中制备了氧化铝含量为95.84%的95氧化铝陶瓷管壳和纯氧化铝陶瓷管壳。氧化铝陶瓷管壳在煅烧过程中发生了形状记忆,氧化铝含量不同,发生形状记忆的温度也不同。95瓷管壳在1200℃开始发生变形,1400℃开始回复原来的状态;而纯氧化铝瓷1250℃开始发生变形,1500℃开始回复原来的状态。对各个温度煅烧的95瓷坯料进行XRD分析表明陶瓷内没有相变的发生,说明氧化铝陶瓷的形状记忆效应不是由相变引起的。初步探讨了氧化铝陶瓷管壳形状记忆效应的机理。     

提高高铝陶瓷耐磨性能研究

实验以工业用Al2O3为主要原料,在MgO-CaO-SiO2系统添加稀土氧化物La2O.和Y2O3,优化配方组成,制备出高性能的研磨介质,其氧化铝含量为98％.实验对陶瓷试样的吸水率和磨损率进行测试表征.采用XRD粉末衍射测试仪和SEM分析了试样的物相组成和显微结构.研究讨论了成形压力和烧结温度对氧化铝陶瓷性能的影响.     

超低钠小原晶α氧化铝的陶瓷烧结性能研究

本文详细研究了低钠小原晶α氧化铝的原晶粒度、Na₂O含量、粉体粒度分布以及烧结温度对陶瓷烧结性能的影响。研究结果表明原晶粒度越小、Na₂O含量越低、粉体粒度越细,所得氧化铝陶瓷越致密。以国内某公司的超低钠小原晶α氧化铝(Na₂O含量0.02%,原晶粒度0.2～0.5μm)为原料,将粉体磨至接近原晶粒度,然后通过造粒、干压所得生坯在1600～1620℃下烧结,陶瓷试块烧结密度达到理论烧结密度的99.5%以上,展现出优良的陶瓷烧结性能。     

高反射率LED陶瓷基板制备及其COB封装光源光效的研究

在普通氧化铝陶瓷基板中,增加气孔率,掺杂ZnO、SnO_2或ZrO_2,将普通陶瓷基板的反射率从92%提高到99%,其中掺杂ZrO_2的氧化铝陶瓷基板,其抗弯强度可以从412MPa提高到787MPa。采用99%高反射率的陶瓷基板制成的1512COB,比采用92%反射率的普通陶瓷基板制成的1512COB,光效高出6%-7%;采用99%高反射率的陶瓷基板制成的1919COB,比采用98%反射率的镜面铝基板制成的1919COB,光效高出1%-2%。     

添加Nd_2O_3对高铝瓷的耐磨性及结构影响

实验以工业氧化铝为主要原料,对Al2O3含量为98%的氧化铝陶瓷进行研究。实验主要过程为:在Ca-MgAl-Si-O体系中添加不同量的稀土氧化物Nd2O3,并在不同温度下烧结,利用X射线粉末衍射(XRD)以及场发射扫描电镜(SEM)对所得复合陶瓷的显微结构和物相组成进行分析,并且测试其吸水率和磨损率。结果表明:Nd2O3掺入使陶瓷晶粒均匀化,并且少量Nd3+可以促进片状晶体的形成,从而使得磨损率获得大幅度的降低。     

添加剂对低温烧结95氧化铝陶瓷性能的影响

采用MnO2-TiO2-CaO-La2O3复相添加剂作为氧化铝陶瓷的烧结助剂,研究了MnO2添加量对95氧化铝陶瓷烧结性能、力学性能和微观结构的影响。结果表明:当配方中MnO2含量为3.0%时,在1550℃烧结温度下制得的氧化铝陶瓷的综合性能最佳,烧结试样的体积密度达到3.76g.cm-3,试样的抗弯强度和洛氏硬度(HRA)分别达到355.22MPa和84.3。     

浅析氧化铝陶瓷制作工艺

氧化铝陶瓷目前分为高纯型与普通型两种。高纯型氧化铝陶瓷系Al2O3含量在99.9%以上的陶瓷材料。由于其烧结温度高达1650～1990℃，透射波长为1～6μm，一般制成熔融玻璃以取代铂坩埚，利用其透光性及可耐碱金属腐蚀性用作钠灯管；在电子工业中可用作集成电路基板与高频绝缘材料。普通型氧化铝陶瓷系按Al2O3含量不同分为99瓷、95瓷、90瓷、85瓷等品种，有时Al2O3含量在80%或75%者也划为普通氧化铝陶瓷系列。其中99氧化铝瓷材料用于制作高温坩埚、耐火管及特殊耐磨材料，如陶瓷轴承、陶瓷密封件及水阀片等。95氧化铝瓷主要用作耐腐蚀、耐磨…     

MgO-TiO_2-La_2O_3系氧化铝陶瓷的力学性能及物相分析

采用MgO-TiO2-La2O3为烧结助剂,利用低温烧结技术制备95氧化铝瓷。研究了烧成温度和助剂含量对氧化铝陶瓷力学性能及物相组成的影响。结果表明:在MgO含量为1.5wt%,TiO2为1.0wt%,La2O3为2.5wt%,1500℃保温2h可得到抗弯强度和硬度分别为348.94MPa和79.6HRA的氧化铝陶瓷。     

耐磨的氧化铝陶瓷

由于致密的氧化铝陶瓷具有较高的机械性能、耐磨性、耐蚀性和较好的大型部件生产能力而被广泛地应用于不同的耐磨部件的生产,研究了由陶瓷防护公司（加拿大）用泥浆浇注和干燥成型方法生产的、氧化铝含量91％－98％（质量）的氧化铝陶瓷的机械性能和耐磨性;讨论了致密陶瓷（如氧化铝基陶瓷）的损毁机理;论述了一些使用氧化铝陶瓷的领域。     

用辊棒废料制备中铝瓷球的烧结机理研究

以辊棒废料为主要原料，在CaO-BaO-SiO2-Al2O3体系中，采用常压低温烧结工艺，研制出含铝量小于60％的高性能中铝瓷球，其磨损率为0．0507％／h，密度为3．1082g／cm^3，与市售90瓷球相比，磨损率与之持平，白度与市售90瓷球不相上下，通过XRD和SEM分析，研究用辊棒废料制备中铝瓷球的烧结机理及其工艺条件对烧结的影响。     

Exploring influence of MgO/CaO on crystallization characteristics to understand fluidity of synthetic coal slags

The crystallization has significant influence on fluidity of slag and slag discharge of entrained-flow-bed(EFB) gasifier. The crystallization characteristics and fluidity of five synthetic slags with different MgO/CaO ratios prepared on the basis of the range of oxide contents of Zhundong coal ash were investigated in this study. The results show that with the MgO/CaO ratio increase, the initial crystallization temperature increases, and the main temperature range of crystallization ratio growth...     

Porcelain tile microstructure: implications for polishability

The present study examines the influence of porcelain tile microstructure on tile polishability and polishing efficiency. A range of different fired porcelain tile microstructures was obtained by varying the quartz particle size and content in the starting composition, and the peak firing temperature.The polishability of these porcelain tile specimens was evaluated with a tribometer designed to simulate the industrial polishing operation, using cement-matrix silicon carbide abrasive tools. The wear rates of both the tile samples and the abrasive tools were measured. A new parameter, termed ‘polishing efficiency’, was defined as the ratio of tile specific wear rate to pin specific wear rate.Quartz particle size and content in the starting composition, as well as peak firing temperature, strongly affected the fired tile microstructure, and hence the polishability. When the firing temperature lies below the optimum value (at which porosity is minimised) the polishing efficiency increases, while the polished surface quality decreases (i.e. porosity rises). Quartz particle size and content should be minimised in the starting composition to achieve maximum polished surface quality and polishing efficiency.     

Sintering of dolomites

A sampling of data on the density of dolomites fired at 1750°C as a function of their chemical composition and structure is presented, and the coefficients of linear correlation are calculated. The most significant coefficients were obtained for the apparent density after firing, the sums of mass fractions CaO+MgO and Fe₂O₃+Al₂O₃, and the fraction of SiO₂ in the dolomite.     

Preparation and Characterization of CaO/MgO Catalyst and Its Application for Transesterification of n-Butyl Acetate with Methanol

This work reports the synthesis and characterization of CaO/MgO mixed oxide with different CaO/MgO mass ratios prepared by the co-precipitation method in a basic medium and subsequent calcination of the precursors. These mixed-oxide materials were characterized by XRD, FT-IR, SEM, and BET. The alkalinity of samples was determined by CO₂ temperature-programmed desorption (CO₂-TPD). Results show that the CaO/MgO samples contained mixed crystalline phases of cubic CaO and hexagonal MgO species. Decreasing the CaO/MgO ratio resulted in low average pore diameter and enhanced BET surface area.

Transesterification of n-butyl acetate with methanol was studied using a CaO/MgO catalyst at atmospheric pressure and 95°C, a model reaction to evaluate the potential of these catalysts for biodiesel production. The highest activity was found for a CaO/MgO mass ratio of 8:2 with conversion percentage of 83. The effects of calcination temperature, reaction time, reaction temperature, methanol/n-butyl acetate molar ratio, and catalyst recycling were investigated.     

Intensification of Sintering of Mullite-Cordierite Ceramics Using Mineralizers

The effect of various mineralizers on the process of sintering of ceramic materials in the MgO – Al₂O₃ – SiO₂ system is investigated. The possibility of decreasing the firing temperature and expanding the firing interval of cordierite-mullite ceramics by using these mineralizers is demonstrated.     

复合生料无光釉的研制

叙述了复合生料釉的研制过程,讨论了MgO、CaO、ZnO、Al_2O_3、SiO_2等氧化物及Al_2O_3/SiO_2比、烧成制度和其他因素对无光釉的影响。     

复合生料无光釉的研制

叙述了复合生料釉的研制过程,讨论了MgO、CaO、ZnO、Al₂O₃、SiO₂等氧化物及Al₂O₃/SiO₂比、烧成制度和其他因素对无光釉的影响。     

CaO/MgO对花岗岩尾矿微晶玻璃物相和性能的影响

以花岗岩尾矿为主要原料(掺入质量分数:56%),TiO₂为主晶核剂,适量Na₂SiF₆为助熔剂和晶核剂,添加部分辅助原料,采用整体析晶法,制备了R₂O-CaO-MgO-Al₂O₃-SiO₂系花岗岩尾矿建筑微晶玻璃。研究了CaO/MgO质量比对微晶玻璃析晶能力、物相、微观结构及性能的影响。结果表明:CaO/MgO质量比的增加有利于增强基础玻璃的析晶能力,当CaO/MgO质量比≤0.88时,微晶玻璃的主晶相为钙长石和角闪石,当CaO/MgO质量比＞0.88时,主晶相转变为钙长石,且钙长石衍射峰的强度随着CaO/MgO质量比的增加而增大;随CaO/MgO质量比的增加,晶体数量逐渐增多,晶粒尺寸增大;微晶玻璃的体积密度和显微硬度随CaO/MgO质量比的增加呈先增大后减小的趋势,当CaO/MgO质量比为0.57时,体积密度达到最大值2.752 5 g/cm³,当CaO/MgO质量比为0.71时,显微硬度达到最大值为8.6 GPa。     

工业废水蒸发残渣主要成分的测定

样品通过烧结处理后,采用重量法测定样品中SiO2和SO24-的含量,采用配位滴定法测定CaO、MgO和Fe2O3的含量。实验结果表明用瓷坩埚代替铂坩埚处理样品可行,SO24-的加标回收率在98.04%～100.0%之间,测定结果令人满意。