ZrO2和TiO2对刚玉质陶瓷蓄热体热震稳定性的影响

采用板状刚玉(＜0.044 mm)、活性氧化铝(d50=1.7 μm)为主要原料,CMC为结合剂,分别制备了无添加剂、添加TiO2、添加ZrO2以及复合添加ZrO2和TiO2 4种刚玉质陶瓷蓄热体试样;试样经1550℃保温2 h热处理后,检测了其热震稳定性、显气孔率和热膨胀系数.结果表明:与无添加剂和单独添加TiO2、单独添加ZrO2的刚玉质陶瓷蓄热体试样相比,复合添加ZrO2和TiO2的刚玉质陶瓷蓄热体试样的热震稳定性显著提高,其原因是:ZrO2的马氏体相变产生微裂纹增韧、钛酸铝(AT)与刚玉的线膨胀系数差形成微裂纹增韧及AT的线膨胀系数低三者协同增韧的机制显著提高了刚玉质陶瓷蓄热体试样的热震稳定性.     

加热炉蓄热式燃烧技术用蜂窝体的研究与应用

蓄热式高温空气燃烧技术（HTAC）是新一代高效节能、环保技术，而其中的蓄热式蜂窝体是该项技术的关键。本文介绍了首钢中厚板轧钢厂2号加热炉蓄热式改造用蜂窝体的材料、性能及其传热、阻力性能研究和实际应用情况。     

蜂窝陶瓷蓄热体的研究现状

介绍了蜂窝陶瓷蓄热体在蓄热节能技术中的发展及应用,详细讨论了蜂窝陶瓷蓄热体的研究现状,尤其是在材质结构以及换热性能的发展及应用中存在的问题,指出了蜂窝陶瓷蓄热体在节能、环保方面的发展方向.     

蓄热氧化炉中蜂窝陶瓷损坏机理及改进措施

结合蓄热氧化技术的工作原理,介绍了蓄热氧化炉关键部件蜂窝陶瓷蓄热体的损坏形式,分析了蜂窝陶瓷蓄热体的损坏原因及影响因素,并提出了延长蜂窝陶瓷蓄热体使用寿命的措施,指出了有待进一步研究的问题,为开发高性能、长寿命的新型蓄热体提供参考。     

蜂窝陶瓷蓄热体的研究现状

综述了高温空气燃烧系统的关键部件之一——蜂窝陶瓷蓄热体的主要发展历程,制备要求以及国内外对蜂窝陶瓷蓄热体热工性能的实验研究和数值模拟现状。可以看出,深入研究蜂窝陶瓷蓄热体的特性对我国发展和应用蓄热式高温空气燃烧技术具有重要意义。     

新型蜂窝陶瓷的研制

开发适用于高效换热器用的蓄热体——对新型蜂窝陶瓷的结构、原料选用、成形方法以及干燥烧结进行了系统研究，使蜂窝陶瓷的抗热震性等性能大大提高，确定了一套合理的生产蜂窝陶瓷的工艺制度，并且使其能够满足生产实际需要。     

蜂窝陶瓷蓄热材料的研究现状

蜂窝陶瓷蓄热材料应该具有热膨胀系数低、比热容大、比表面积大、导热性能好、抗热震性好等特性。本文详细介绍了几种多孔陶瓷材料的优缺点,指出堇青石质复相材料是目前研究最广泛的蜂窝陶瓷材料。堇青石与多种催化剂匹配性好,比表面积大、热膨胀系数小,但耐热性稍差,于是通过添加一些添加剂来提高堇青石作为蜂窝陶瓷蓄热体的性能。这些添加剂与堇青石结合形成复相材料,可以降低热膨胀系数、提高抗热震性等。     

陶瓷蓄热体的研究现状及应用

陶瓷蓄热体作为陶瓷蓄热技术中的关键部件，它的性能决定了余热回收体系的整体性能。着重对蜂窝陶瓷蓄热体在制备及使用过程中存在的主要问题及解决措施进行了较详细的论述。同时对新型的潜热型复合相变蓄热体的研究现状及发展趋势进行了简单论述。     

莫来石蜂窝陶瓷的阻力特性

本文以实验为基础,通过搭建的蜂窝陶瓷蓄热体阻力特性实验台,对莫来石蜂窝陶瓷的阻力特性进行了实验研究。研究表明:蜂窝陶瓷的阻力损失随蓄热体长度增加而增大,随孔隙率增加而减小;在蜂窝陶瓷的长度一定时,其阻力损失随雷诺数增加而增大,随气体流速增加而增大。根据实验数据得到了蜂窝陶瓷蓄热体摩擦阻力系数实验关联式,为煤矿乏风氧化装置的设计提供了数据支持。     

蜂窝陶瓷蓄热体的热应力研究

建立蜂窝陶瓷的正六边形单通道数学模型,利用CFX流体计算软件,对蜂窝陶瓷在蓄热和放热时的温度分布规律进行了研究,并将数值计算结果与实验结果进行了对比分析,来验证仿真计算结果的可信性。计算分析了不同入口速度以及相同入口条件下不同时刻蜂窝陶瓷的热应力分布情况,结果表明,蓄热体的入口速度越大,应力越大;相同入口条件下,拉应力在蓄热体两端较大,中间较小。     

陶瓷涂层三明治板的抗热震性

采用解析法研究了第3类边界条件下双面陶瓷涂层三明治板的瞬态温度场及瞬态热应力场.对不同Biot模数的热冲击过程中,Al2O3涂层/硬质合金(WC-8%Co,质量分数)基体/Al2O3涂层三明治板的瞬态热应力进行了数值计算.分析了涂层/基体厚度比、涂层与基体热-物理性能匹配对陶瓷涂层三明治板表面热应力峰值的影响.结果表明:陶瓷涂层三明治板的基体的热导率、线膨胀系数和弹性模量应高于涂层,这样可以降低其表面热应力,获得高抗热震性陶瓷涂层三明治板.此外,涂层厚度应尽可能小,以利于改善涂层的抗热震性.     

陶瓷圆柱体的抗热震参数

通过求解第三类边界条件下无限长圆柱体的瞬态温度场及瞬态热应力场，研究了陶瓷圆柱体的抗热冲击行为，建立了引起无限长陶瓷圆柱体表面临界热应力的临界温差表达式，并以此作为陶瓷圆柱体的抗热震参数。计算结果表明，无限长陶瓷圆柱体的临界温差大于具有相同Biot模数的无限大陶瓷平板的临界温差，但其表面达到临界热应力的时间小于无限大平板的数值。     

梯度功能陶瓷圆球的抗热震性

推导和提出了第三类边界条件下梯度功能材料(functionally gradient materials,FGM)圆球的瞬态温度场及瞬态热应力场表达式.基于陶瓷材料的临界应力断裂判据,通过求解梯度功能陶瓷圆球表面达到其局部断裂强度的时间,建立了引起其表面临界热应力的临界温差△Tc的表达式,并以此作为梯度功能陶瓷圆球的抗热震参数.通过计算实例并与均质陶瓷圆球对比,分析了材料的热-物理性能分布规律对其抗热震性的影响,并提出了高抗热震性FGM陶瓷圆球的设计原则:线膨胀系数和热扩散率应由表及里增大,而弹性模量应由表及里减小.     

原位生成堇青石结合红柱石太阳能热发电储热陶瓷的抗热震性能

为提高储热陶瓷材料的抗热震性能,采用原位生成堇青石增强技术,以红柱石为主要原料,通过半干压成型,无压烧结研制了用于太阳能高温热发电红柱石储热陶瓷材料样品。研究了配方组成、烧成温度、相组成、微观结构对样品抗热震性能的影响。结果表明：红柱石添加量为 70%,经1 400 ℃烧成的样品抗热震性能最佳：30 次热震实验（热震条件：1 100 ℃～室温,风冷）的强度不仅没有损失,反而增加了 26.20%。相组成和微观结构分析表明样品的晶相为堇青石、莫来石、硅线石、α-方石英、α-石英等,原位生成的堇青石晶体均匀分布在由红柱石转化的莫来石晶体之间,赋予样品较好的抗热震性能     

Thermal shock resistance behavior of auxetic ceramic honeycombs with a central crack or an edge crack

In this paper, the thermal shock resistance of an auxetic ceramic honeycomb plate is studied based on the fracture mechanics concept for the cases of a central crack or an edge crack. The transient temperature field and transient thermal stress field are obtained for both auxetic and non-auxetic structures. The relationship between the thermal stress intensity factor (TSIF) and the internal cell angle, crack length and time is determined and the critical temperature for the initiation of crack propagation is predicted. Results show that compared with the non-auxetic ceramic honeycombs which are at an internal cell angle of 30°, the critical temperature of the auxetic ceramic honeycombs whose cell are orientated at an angle of −30° increases by 78.5% and the TSIF at the crack tip decreases by 40%, respectively. Hence, the auxetic structures have better thermal shock resistance. This study indicates that auxetic ceramic honeycombs have significant potential applications in harsh temperature environments.     

NZP陶瓷增压器蜗壳隔热管的研制

NZP陶瓷具有低膨胀、低导热、高抗热震性，是用于隔热抗热震场合的理想材料，本文采用沉淀法合成CM粉料、等静压成型、分段烧成制度，成功地制备出NZP陶瓷增压器蜗壳隔热管。     

Catalytic Activity of Ceramic Honeycombs in the Exhaust Gas Oxidation of a Waste Treatment Plant

The activity of ceramic honeycombs with varying material composition and degree of utilization is compared on a suitable model gas in a test plant. The tested honeycombs are standard products that have not been surface‐treated in any way. A propane‐air mixture was fed to the test plant and then oxidized in a high‐temperature furnace. The analysis of the conversion rate over the reaction temperature showed remarkable differences in activity. The honeycomb with the most promising results was further investigated with the exhaust gas from the drying process of a waste treatment plant. Finally, the activity of this honeycomb was assessed in a large‐scale trial in an existing running regenerative thermal oxidizer.     

Comparative investigation of ultrafast thermal shock of Ti3AlC2 ceramic in water and air

In this work, ultrafast thermal shock of Ti₃AlC₂ ceramic was evaluated in water and air by utilizing the induction heating method. First, the annealed samples were heated to the set temperature in tens of seconds and dropped into the cooling water within 0.1 s which is rather short not to degrade the sample temperature. Compared to the traditional thermal shock method when quenching in water, the abnormal thermal shock phenomenon did not occur, which is owing to that no dense oxide layers were formed on the samples’ surface to act as the thermal barrier. The continuous decrease in residual flexural strength when quenched in water is associated with water infiltration, chemical reaction, and large surface tensile stress. The residual strength has 27.25 MPa upon 1250°C. Second, at the same testing temperature, the residual flexural strength when quenched in air maintains a high value of 388 MPa up to 1400°C. Dense oxide scales existed on the quenched surface of Ti₃AlC₂ samples. The results exhibit that Ti₃AlC₂ ceramic possesses excellent thermal shock resistance in water and air, suitable to be applied in extreme environments.     

对称型梯度功能陶瓷材料抗热震性的研究

通过水淬实验并结合热冲击过程瞬态热应力场的计算，研究了Al2O3/W(W,Ti）C系列对型梯度功能陶瓷材料的抗热震性能。结果表明，采用合理的梯度组成分布规律可提高陶瓷材料的抗热震性。     

Observation of ceramic cracking during quenching

It is difficult to observe the thermal shock cracking in real time, so the measurement of the crack after thermal shock is considered as an alternative method. This paper proposes a new experimental method which can exhibit the thermal shock cracking in real time by water quenching of translucent ceramic and high‐speed imaging. The crack propagation is captured, and the crack growth rate is calculated. The results confirm the previous theoretical predictions of crack propagation under thermal shock. This paper expands the research on understanding the failure mechanisms of ceramic materials in thermal shock.