氧化铁粉对MgO-Al2O3质浇注料性能的影响

以电熔镁砂、二氧化硅微粉、MA尖晶石粉、α-Al2O3微粉、氧化铁粉为原料制备MgO-Al2O3质浇注料,研究氧化铁粉加入量(0、2%、4%、6%)对MgO-Al2O3质浇注料常温物理性能、抗热震性和抗渣性的影响.按照国家相关标准进行各项物理性能检测,并用X射线衍射仪对1550℃3 h烧后试样进行物相分析,采用风冷法进行抗热震性试验,静态坩埚法进行抗渣试验.结果表明加入氧化铁粉对MgO-Al2O3质浇注料的抗渣渗透性能和常温力学性能有利.随着基质中氧化铁粉加入量的增加,试样抗渣侵蚀能力有所减弱,抗渣渗透能力明显增强,试样经1100℃3 h和1550℃3 h热处理后的常温力学性能得以提高,但抗热震性降低.氧化铁粉加入量≤2%时,试样的抗热震性较好.     

ZrB_2对Al-Si复合Al_2O_3-C材料高温力学性能的影响

以板状刚玉、α-Al2O3微粉、Al粉、Si粉、ZrB2和石墨为原料,酚醛树脂为结合剂,采用150 MPa压力压制成25 mm×25 mm×145 mm的试样。研究ZrB2加入量(其质量分数分别为0.5%、1%、1.5%、2%)对Al-Si复合Al2O3-C材料高温抗折强度和抗热震性的影响,并分析了试样物相组成和显微结构的变化。结果表明:(1)加入ZrB2质量分数≥1%时,可明显提高200℃烘烤和700℃热处理后试样的高温抗折强度和抗热震性;加入ZrB2对1 500℃烧后试样的高温抗折强度和抗热震性影响不大。(2)加入ZrB2后AlN和SiC生成量明显增加,晶体发育良好,形成连续交叉连锁的网络结构,对材料增强、增韧作用显著,有利于提高材料的高温强度和抗热震性。     

ZrO_2微粉添加量对高温气固分离用氧化铝陶瓷膜性能的影响

为了调控氧化铝陶瓷膜的孔径大小及分布,并提高其抗热震性能,在平均粒径为20μm的氧化铝粉中添加不同量的中位粒径为2μm的Zr O_2微粉(Zr O_2微粉分别占混合粉质量的0、10%、20%、30%、40%),再加入结合剂等,经配料、制浆、莫来石支撑体浸渍、110℃干燥和1 300℃保温2 h煅烧后,制成氧化铝陶瓷膜试样,研究了Zr O_2微粉加入量对陶瓷膜孔径大小、孔径分布、孔隙率、透气度和抗热震性的影响。结果表明:随着Zr O_2微粉加入量的增加,陶瓷膜的最可几孔径、孔隙率和透气度均逐渐减小,孔径分布变窄,抗热震性提高。在满足高温烟气气固分离使用要求的条件下,氧化铝粉中Zr O_2微粉加入量以20%(w)为宜。     

SiO2微粉加入量对刚玉质超低水泥浇注料高温性能的影响

研究了SiO2微粉加入量为0、2%、4%、6%和8%时对刚玉质超低水泥浇注料的烧结性能、高温强度及抗热震性能的影响.结果表明随着SiO2微粉加入量的增加,试样的烧结性能和抗热震性得到明显改善,在1400℃时的高温抗折强度也显著提高.讨论认为,试样高温性能提高的主要原因是SiO2微粉与Al2O3反应生成的莫来石穿插或弥散在刚玉颗粒形成的骨架结构的孔隙中起增韧作用.     

锆刚玉-莫来石质泡沫陶瓷过滤器的研制

以刚玉粉、锆英石粉、SiO2微粉、聚乙烯亚胺(PEI)等为主要原料,以孔数(PPI)为10~15的软质聚氨酯泡沫为载体,采用有机泡沫浸渍法于1400℃6h烧后制备了锆刚玉-莫来石质泡沫陶瓷过滤器,分别研究了聚乙烯亚胺、锆英石和SiO2微粉的加入量对浆料稳定性、过滤器强度和抗热震性的影响。结果表明:当聚乙烯亚胺加入量为0.08%(质量分数,下同),锆英石加入量为20%,SiO2微粉加入量为3%时,采用合适的工艺可制备出气孔率大,强度高,抗热震性好的锆刚玉-莫来石质泡沫陶瓷材料。其具体性能指标为:气孔率83%,耐压强度2.4MPa,抗折强度为1.3MPa,抗热震性达6次。     

镁砂粉加入量对RH浸渍管浇注料性能的影响

以烧结刚玉为主要原料 ,同时加入镁砂粉、铝酸钙水泥、α Al2 O3微粉等 ,研究了镁砂粉加入量对RH浸渍管用刚玉质浇注料的抗热震性、抗渣性和热膨胀性的影响。结果表明 ,在刚玉质浇注料中加入适量的镁砂粉 ,高温下可以形成镁铝尖晶石 ,这是提高浇注料的热震稳定性和抗渣侵蚀性的主要原因。镁砂粉的加入量为 6 %时 ,RH管浇注料的上述性能良好     

加入纳米碳酸钙对刚玉-尖晶石质浇注料性能的影响

以烧结刚玉为骨料,电熔白刚玉粉、电熔尖晶石粉、α-Al2O3微粉、纳米碳酸钙以及水合氧化铝为基质,研究了纳米碳酸钙加入量(质量分数分别为0.4％、0.8％、1.2％、1.6％、2.0％)对刚玉-尖晶石质浇注料经不同温度处理后抗折强度、抗热震性和抗渣性的影响.结果表明:加入的纳米碳酸钙在高温下分解,并原位生成铝酸钙系矿物,能明显提高浇注料在800～1400 ℃处理后的常温和热态抗折强度;加入纳米碳酸钙能明显提高浇注料的抗热震性能,对浇注料抗高碱度渣性能的影响较小,但明显降低了其抗低碱度渣的侵蚀性和渗透性.     

硅粉加入量对转炉无水副枪用刚玉-莫来石浇注料性能的影响

为改善转炉无水副枪用浇注料的抗热震性,以质量分数分别为71%的板状刚玉、14%的烧结莫来石、3%的CA80水泥、2%的SiO_2微粉、10%的α-Al_2O_3微粉制备了刚玉-莫来石浇注料试样,研究了硅粉外加量(质量分数分别为0、1%、2%、3%、4%)对不同温度处理后试样性能的影响。结果表明:随着硅粉加入量增加,试样由收缩逐渐变为膨胀,试样的体积密度、常温抗折强度和常温耐压强度略有增加,显气孔率逐渐降低; 1 550℃处理后试样抗热震性能有所增加,且在硅粉加入量为2%(w)时试样的抗热震性最佳,强度保持率为48%。硅粉氧化为SiO_2后与Al_2O_3反应原位生成莫来石产生体积膨胀,在试样内部形成了一定量的微裂纹,提高了试样的抗热震性。     

镍基高温合金陶瓷涂层的制备及性能表征

以Cr2O3粉、玻璃料及黏土为原料制成料浆,通过喷涂将其涂覆在镍基高温合金GH44的表面,采用热化学反应法于1050°C保温10min,熔烧制备出高温陶瓷涂层。通过扫描电镜和X射线衍射分析了高温陶瓷涂层的表面和截面形貌以及相组成,对涂覆陶瓷涂层的镍基合金的抗热震性能、抗氧化性能以及高温疲劳性能进行了测试。结果表明,陶瓷涂层结构致密,与基体结合牢固,具有良好的抗热震性能。涂覆陶瓷涂层的镍基合金其高温抗氧化性相对于基体提高了6倍以上,其高温疲劳性能明显改善。     

不同铝基原料对MgO-Al-C材料性能和显微结构的影响

以烧结镁砂骨料、电熔镁砂细粉、Al粉、N220炭黑为原料,酚醛树脂为结合剂,制备MgO-Al-C材料,研究了三种铝基原料(造粒氧化铝微粉、氧化铝空心微珠、六铝酸钙)对其常温抗折强度、高温抗折强度、抗热震性及抗氧化性的影响,并借助XRD和SEM对其物相组成及显微结构进行分析。结果表明,造粒氧化铝微粉是多孔结构,可吸收热应力,加入量为1%(质量分数,下同)时,可提高材料的常温抗折强度和抗热震性,明显改善材料的抗氧化性。氧化铝空心微珠是中空结构,可缓冲热应力,加入量为3%时,可明显提高材料的常温抗折强度,并具有较高的抗热震性和抗氧化性。六铝酸钙的热膨胀系数较低,可赋予材料较好的韧性,加入量不超过5%时,样品具有较好的抗热震性。     

关于逆流冷却塔雨区阻力计算的探讨

在逆流式冷却塔的空气阻力计算中,常常忽略了雨区阻力的计算,包括国标规范与高等教育的教科书等权威文献也未提及,根据工业塔的实测,这部分阻力占全塔空气阻力的1/6左右。本文根据冷却塔设计与运行的实践,并结合国内外学者对此的实验研究成果,经分析总结,给出了一个较为系统可行的计算方法,经验证与工业塔实测基本吻合,可供冷却塔设计中参考使用。     

耐高温尼龙聚邻苯二甲酰胺的研究进展

综述了聚邻苯二甲酰胺(PPA)的特性和应用,对部分PPA新品种制备方法及表征测试作了介绍,还介绍了PPA在耐热性、吸水性、尺寸稳定性、耐焊锡性等方面的研究进展。     

Improving the bending and corrosion resistance of an enamel by the addition of β-Si3N4 whiskers

Enamel–metal composite materials with high strength and corrosion resistance are often used for fabricating enameled pressure vessels for pharmaceutical and chemical production. However, the low bending resistance of the enamel can result in the cracking and delamination of the enamel layer, leading to the loss of corrosion resistance of the enameled pressure vessel, which can result in accidents. Here, based on the goal of increasing the bending resistance of the enamel to prolong its service life, the effect of β-Si₃N₄ whiskers on the mechanical properties of enamel was studied by three-point bending tests. The effect of β-Si₃N₄ whiskers on the acid and alkali corrosion resistance of enamel was studied using aqueous H₂SO₄ and NaOH solutions, respectively. A sudden change in the force of an enameled sample under the three-point bending test was used to evaluate the bending resistance of the enamel–metal samples, and can also be used to evaluate the mechanical properties of other comparable materials. With the addition of 0.5 wt% β-Si₃N₄ whiskers, the bending resistance was significantly improved, along with the acid and alkali corrosion resistance. These findings are expected to provide guidance for the design and production of enamel-metal vessels with improved performance that can significantly lengthen the service life of enameled pressure vessels and reduce the occurrence of accidents.     

电阻器专用涂料(Ⅰ)

介绍了电阻涂料底漆、面漆的种类和各类电阻涂料底漆和面漆的组成、特点及技术规格。同时,还简介了环氧型、油墨型及有机硅型标志涂料的特点和技术指标。     

Effect of partial substitution of alumina–chromium slag for Al2O3 on microstructures and properties of Al2O3–SiC–C trough castables

Alumina–chromium slag (ACS), a cheap and abundant refractory raw material comprising aluminum–chromium oxides and β-Al₂O₃, is a byproduct of ferrochrome smelting. For this reason, we investigated the relationships between composition and mechanical properties, abrasion resistance, oxidation resistance, and resistance to iron slag erosion for Al₂O₃–SiC–C trough castables in which ACS was substituted for alumina. Due to the presence of β-Al₂O₃ in ACS, the aluminum-chromium slag reacted with SiO₂ to form a low-melting phase of albite and promoted the formation of mullite, which filled the pores at high temperatures and reduced the porosity, thereby promoting densification and strengthening of the sample. The cold mechanical properties of the sample and the normal temperature wear resistance were enhanced, but the high-temperature mechanical properties and the resistance to iron slag corrosion of the sample were impaired. According to the results of the anti-oxidation experiment, the presence of β-Al₂O₃ in the ACS reduced the porosity and made the sample more dense, which remarkably improved oxidation resistance of the sample. For industrial production requirements, ACS substitution should not exceed 48?wt% due to of thermomechanical properties and anti-slag corrosion performance in Al₂O₃–SiC–C trough castables.     

Enhancement of thermal shock and slag corrosion resistance of MgO–ZrO2 ceramics by doping CeO2

The purpose of this paper was to develop ceramics materials with high thermal shock resistance and corrosion resistance for preparing gas blowing components. In this paper, MgO-rich MgO–ZrO₂ ceramics were obtained by using MgO powder and ZrO₂ powder as starting materials and CeO₂ as an additive. Changes in the properties in terms of thermal shock resistance, mechanical properties, and slag corrosion-resistance with chemical compositions were examined correlated to microstructure and phase changes. Especially, the effect of doping CeO₂ on phase transition of zirconia in MgO-rich system was discussed. The results showed that doping amount of CeO₂ significantly improved properties of MgO–ZrO₂ ceramics. Especially when doping amount of CeO₂ was 2 wt%, residual strength ratio was enhanced over 100% after thermal shock testing. In samples doped with CeO₂, ZrO₂ was stable in cubic or tetragonal form due to complete solution of CeO₂, which was important reason for the improvement of various properties of MgO–ZrO₂ ceramics.     

氧化镁-尖晶石浇注料的组成与性能的关系

以中档烧结镁砂、矾土基尖晶石和电熔白刚玉为主要原料,制备了不同基质组成的试样,并研究了浇注料的流动性、强度、永久线变化率、抗渣性和抗热震性。结果表明：基质的组成（特别是Ａｌ２Ｏ３／ＭｇＯ比）对浇注料的抗渣性、线变化率、抗剥落性和热震稳定性有显著影响,通过调整Ａｌ２Ｏ３／ＭｇＯ比可制得综合性能优良的氧化镁－尖晶石浇注料     

硅树脂及其涂料的研究新进展

综述了近十年来国内外耐热、耐腐蚀、耐候性硅树脂、改性硅树脂及其涂料的研究新进展；指出了硅树脂及其涂料的发展趋势。     

钢骨架塑料复合管的性能和应用

对钢骨架塑料复合管与其他管道的性能进行了比较,对比结果证明:钢骨架塑料复合管具有耐压、耐磨、耐腐蚀、抗蠕变、安装方便以及较高的性价比等特点。     

无醛防皱整理剂的研究进展

传统的防皱整理的发展历程及面临的新问题，阐述了多元羧酸类防皱整理剂作为棉织物理想的无甲醛防皱整理剂的防皱机理及性能，但由于它存在价格贵、织物泛黄色变、耐洗牢度差、含磷催化剂污染环境等问题，需要有效解决。最后，指出了无醛防皱整理今后的发展方向。