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铁矿渣矿化剂对硅微粉结合SiC窑具材料晶相结构与性能的影响 总被引:1,自引:0,他引:1
在硅微粉结合的SiC窑具材料中添加不同含量的铁矿渣,铁矿渣中的Fe2O3在高温下形成一定数量的液相,能使硅微粉析出的α—方石英转变为稳定的α—磷石英,提高窑具材料的热稳定性和强度,延长使用寿命。本文主要探讨不同含量的铁矿渣对窑具材料力学性能和抗氧化性能的影响。实验结果表明,确定0.4wt%铁矿渣为最佳加入量。窑具的抗折强度为21.2MPa,1次和10次热震抗折强度保持率分别为47.3%和46.6%。经12小时氧化的氧化度为0.0061%,与其他试样相比,氧化速度大大降低。 相似文献
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堇青石/莫来石比值对硅微粉结合莫来石-堇青石窑具材料结构与性能影响 总被引:2,自引:0,他引:2
采用硅微粉结合的莫来石-堇青石窑具是固体废弃物综合利用,变废为宝的研究项目。硅微粉尘是硅铁电炉冶炼过程产生的大量烟尘,属于玻璃体,尺寸为纳米级,高活性,能促进窑具材料的烧结和提高窑具性能。经XRD和SEM分析结果,各试样存在四种晶相α-堇青石,β-堇青石,μ-堇青石和莫来石。堇青石/莫来石比值从2.33变化到1.5时,堇青石从83.8%增加到85.3%,莫来石从15.4%降低到14.7%;堇青石,莫来石比值从1.5降低至0.67时,堇青石含量随比值下降而降低,莫来石随比值降低而增加。综合分析结果确定3^#为最佳配方,存在的堇青石与莫来石的晶相比例合理,抗折强度最高(27.41Mpa),1次和10次热震抗折强度保持率最高(67%和46%),气孔率和收缩率较低,体积密度最高,这种配方的窑具材料热稳定性好,强度高,使用寿命长。 相似文献
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在硅微粉结合的SiC窑具材料中添加少量的铁矿渣矿化剂,使窑具在高温下形成一定量的液相,能使体积效应大的α-方石英转化成体积效应小的α-鳞石英,降低窑具的体积效应和提高热稳定性。同时形成的液相能使S i C表面形成一层致密的保护膜,堵塞气孔,隔离O2与SiC的接触,降低在界面上进行的氧化反应速度,以达到抗氧化的目的。实验结果表明:添加0.4%铁矿渣矿化剂的氧化度最小(G=6.1x10-5),确定0.4%为最佳的铁矿渣加入量。在1300℃下铁矿渣添加量分别为0和0.4wt%时的氧化动力学方程分别为:F(G1)=3.17×10-9,F(G2)=1.75×10-9 相似文献
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MnO2-CaF2混合矿化剂能改善硅微粉析晶结构,增加磷石英的含量,从而改善窑具的高温性能,延长使用寿命;采用XRD法测定析晶结构,并测定窑具的抗折强度、抗折强度保持率、气孔率、吸水率等各项性能指标,综合分析得出MnO2-CaF2混合矿化剂的最佳加入量为2%。 相似文献
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向水淬后的Li2O-Al2O3-SiO2系统玻璃粉中加入石英玻璃粉,参照玻璃粉末的DTA曲线确定晶化温度,采用烧结法制备出了低膨胀微晶玻璃材料。运用XRD分析了材料的晶相种类,测定了材料的热膨胀系数、密度、抗折强度等性能,分析讨论了石英玻璃粉对材料性能的影响结果表明,石英玻璃粉含量增大,材料的热膨胀系数值减小。密度值增大,抗折强度值降低,析出主晶相为β-锂辉石固溶体。 相似文献
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研究用铝型材厂污泥合成的莫来石窑具经过不同使用周期后的晶相结构及性能的变化,探讨窑具的破坏机理,从而为提高窑具材料的质量,延长其使用寿命提供理论基础。采用XBD和SEM表征晶相结构与显微结构;用gietveld quantification法确定各试样的晶相含量,用PhiIips Plus软件确定各试样的晶胞参数与晶胞体积;并测试吸水率、显气孔率和抗折强度等性能指标。结果表明:窑具中莫来石的含量相对稳定;随使用次数的增加,莫来石晶体由针状逐渐变为柱状,尺寸变长,最后出现裂纹;窑具材料在使用过程中各性能指标的变化不大,吸水率和显气孔率有少量增加,体积密度少量下降。 相似文献
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采用电子陶瓷工艺制备了一系列钙长石/玻璃复合材料,并对复合材料进行X射线分析、扫描电镜观察和性能测试。结果表明:复合材料的介电常数、热膨胀系数随钙长石含量的增加而增加,而介电损耗和抗折强度随钙长石含量的增加而减小。钙长石含量大于50wt%的复合材料中α-石英和方石英的析出增加了材料的热膨胀系数,但对材料的介电性能影响不大。所制备的复合材料具有低的介电常数(5.4~6.1)、低的介电损耗(0.11%~0.41%)、低的热膨胀系数(4.3×10^-6~6.1×10^-6/℃)和低的烧结温度(≤900℃),有望用于电子封装领域。 相似文献
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CaF2-CaO矿化剂对硅微粉结合的SiC窑具的晶相性能影响的研究 总被引:5,自引:1,他引:4
本研究主要探讨矿化剂对硅微粉结合的SiC窑具的析晶结构、性能的影响。分别添加不同量的混合矿化剂,用XRD法分析硅微粉的析晶结构,并进行半定量计算,选择最佳的矿化剂添加量,分别测定不同矿化剂添加量时窑具的各项宏观性能,进行综合分析,确定CaF2~CaO矿化剂的最佳添加量为1.5%。 相似文献
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ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l/3为氧气,2/3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中:A一混… 相似文献
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P. P. Budnikoff 《Journal of the American Ceramic Society》1924,7(11):817-820
The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO3 and determination of CaO by KMnO4 titration, the SO3 by Andrews method of titration of BaCrO4 has been found to give very reliable results with the least consumption of time. 相似文献
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A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases. 相似文献
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A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.
Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology. 相似文献
Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology. 相似文献
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ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES 总被引:5,自引:0,他引:5
Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log10 viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log10 viscosity as a function of soda content are smooth up to 50% Na2O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO2, 2Na2O) due to Molecular Substitution of CaO, MgO and Al2O3 for Na2O The effect is clearly brought out by plotting (from the results of English) the change of log10η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature Ta. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log10η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A12O3) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al2O3) per 100°. At the aggregation temperature the change of log10η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al2O3. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log10η due to substitution of an oxide for Na2O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na2O-CaO-SiO2. Change of Viscosity of Glass (4SiO2, 2Na2O) due to of Substitution of B2O3 for SiO2 The change of log10η (from the results of English) is plotted as a function of temperature, and also the change of log10η per per cent B2O3. The curves are more complex than for the substitution for Na2O. 相似文献
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面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。 相似文献