窑具抗热震性评价方法的研究

针对现有抗热震方法在评价窑具材料时存在的局限性,在YB/T376.3-2004水急冷-裂纹判定法的基础上,提出了空气急冷-裂纹判定法。结果表明该方法适合于窑具材料抗热震性的评价。相同材质、相同形状的刚玉-莫来石质窑具的热震次数与使用次数存在相关性。而对相同材质、不同形状或不同材质、相同形状的窑具之间,不适合进行抗热震性的对比。该方法测定的热震次数与水急冷法的结果差别较大,水急冷法的热震次数明显高于空气急冷-裂纹判定法。     

纤维对莫来石-刚玉高温窑具性能的影响

莫来石-刚玉质高温窑具以工业氧化铝和莫来石为主要原料加工而成,材料主要组分为莫来石和刚玉。该窑具具有较高的使用温度(不低于1350℃)、高温强度和化学稳定性,与承烧制品的化学相容性好,特别适用于承烧软磁体(铁氧体)材料和电子绝缘陶瓷。但该材质窑具的抗热震性较差,而要提高抗热震性却又降低了高温强度,存在抗热震性和高温强度之间的矛盾,本文研究了引入纤维的引入对莫来石-刚玉窑具性能的影响。     

不同结合方式碳化硅质窑具材料的抗热震性研究

概述了不同结合方式的碳化硅（SiC）质窑具材料的抗热震性能．表明Si2N2O结合SiC窑具材料的抗热震性优于其它结合方式的SiC窑具材料。并对Si2N2O结合SiC窑具材料抗热震性的影响因素进行了较系统的研究。结果表明：当Si2N2O含量≤20％时，增加Si2N2O含量．可提高Si2N2o结合SiC试样的抗热震性；当Si2N2O含量超过20％时，试样的抗热震性能反而变差，Si2N2O结合SiC试样的抗热震性优于Si3N4结合SiC试样。固定试样中Si2N2O的含量为25％，当Si／SiO2（摩尔分数）在2．7％～3．3％范围内时，增加Si／SiO2（摩尔分数）可提高试样的抗热震性，而当Si／SiO2（摩尔分数）在3．3％～4％范围内时．增加Si／SiO2（摩尔分数）对试样抗热震性的影响规律不明显。     

提高氮化硅结合碳化硅窑具使用性能的研究

氮化硅结合碳化硅窑具的抗热震性能被破坏、不合理的支撑方式、承重变形因素导致其使用性能降低,影响了氮化硅结合碳化硅窑具的使用寿命。本研究制备了氮化硅结合碳化硅窑具,并结合生产实际主要研究了如何提高材料的抗氧化性、抗热震性以及其他高温理化性能,使氮化硅结合碳化硅窑具使用寿命延长。     

纤维对莫来石-刚玉质高温窑具性能的影响

莫来石-刚玉质高温窑具是以工业氧化铝和莫来石为主要原料加工而成，材料主要组分为莫来石和刚玉。该窑具具有较高的使用温度（不低于1350℃）、高温强度和化学稳定性，与承烧制品的化学相容性好，特别适用于承烧软磁体（铁氧体）材料和电子绝缘陶瓷。但该材质窑具的抗热震性较差，若提高抗热震性却叉降低了高温强度，存在抗热震性和高温强度之间的矛盾，因此研究了纤维的引入对莫来石-刚玉质窑具性能的影响。     

不烧改性树脂结合碳化硅材料的性能研究

为了开发具有更高抗热震性的陶瓷窑具,以优质碳化硅为原料,含Si、O、C、H元素的改性树脂为结合剂,研制了不烧改性树脂结合碳化硅材料,并重点对该材料的抗热震性、高温荷重变形性、高温抗折强度进行了试验研究。结果表明:该碳化硅材料具有非常好的抗热震性、高温强度和很好的抵抗高温载荷的能力,在陶瓷窑具等温度波动大的环境下应该有很好的应用前景。     

熔融石英窑具材料抗热震性与析晶性的研究

本文主要研究粘土结合的熔融石英窑具材料的组成，烧成温度，保温时间对窑具材料的抗热震性与结晶性的影响。     

钛酸铝对堇青石质窑具性能的影响

探讨了钛酸铝 (AT)对堇青石质窑具机械强度和抗热震性的影响 ,分析了窑具材料在使用过程中存在的问题 ,并提出了解决方案。     

影响窑具使用寿命的因素及提高窑具抗热震性途径

概述了我国窑具行业的现状,运用理论和实践分析了影响窑具使用寿命的因素,并提出了提高窑具抗热震性的途径。     

改进抗热震性的碳化硅窑具材料

本文针对粘土结合碳化硅窑具材料热稳定性尚不十分理想的现状、改变结合剂的组成和材料的结构特性，从而提高了这种材料的抗热震性和扩大其应用范围。     

莫来石-钛酸铝陶瓷材料性能的研究

用预合成的钛酸铝制备了莫来石-钛酸铝(MT)陶瓷材料,研究了材料组成与其烧结性能、抗弯强度、热膨胀性能及抗热震性的关系。结果表明,随着钛酸铝含量的减少,MT陶瓷材料的抗弯强度提高,热膨胀系数增大,抗热震性降低,但在钛酸铝含量大于43％时,陶瓷材料的强度有所增加,仍保持较低的热膨胀系数,具有良好的抗热震性。     

A multi-scale model for predicting the thermal shock resistance of porous ceramics with temperature-dependent material properties

This paper develops a novel multi-scale thermal/mechanical analysis model which not only can efficiently measure the thermal shock response but also highly reflects the effects of diversiform micro-structures of porous ceramics. Knowledge of the temperature distribution and time-varied thermal stress intensity factors (SIF) is derived by finite element/finite difference method and the weight function method in the macro continuum model. The finite element analysis employs a micro-mechanical model in conjunction with the macro model for the purpose of relating the SIF to the thermal stress in the struts of the porous ceramics. The micro model around the crack tip was established by using Voronoi lattices to accurately explore the micro-architectural features of porous ceramics. Hot shock induced center crack and cold shock induced edge crack are both considered. Effects of relative density and pore size on the thermal shock resistance are investigated and the results are well coincident with the experimental tests. The influence of cell regularity and cross section shape of the cell struts is discussed and the corresponding explanations are provided. The importance of incorporating temperature-dependent material properties on the thermal shock resistance prediction is quantitatively represented. These multi-faceted models and results provide a significant guide to the design and selection of porous ceramics against the thermal shock fracture failure for the future thermal protection system of space shuttle.     

反应烧结碳化硅材料的抗热震性能研究

通过对比不同温差热震后材料的残余强度 ,对反应烧结碳化硅材料的抗热震性能进行了研究。结果表明 :反应烧结碳化硅材料的抗热震性能与显微组织密切相关 ,低游离硅含量与小粒径的反应烧结碳化硅材料具有较好的抗热震断裂性能 ,而高游离硅含量或大碳化硅粒径的材料具有相对优异的抗热震损伤性。对反应烧结碳化硅材料的抗热震性与显微组织的关系进行了探讨。     

Preparation and thermal stability investigation of Al2O3–mullite–ZrO2–SiC composite ceramics for solar thermal transmission pipelines

To obtain composite ceramics with excellent thermal shock resistance and satisfactory high?temperature service performance for solar thermal transmission pipelines, SiC additive was incorporated into Al₂O₃?mullite?ZrO₂ composite ceramics through a pressureless sintering process. The effect of the SiC additive on thermal shock resistance was studied. Also, the variations in the microstructure and physical properties during thermal cycles at 1300 °C were discussed. The results showed that both thermal shock resistance and thermal cycling performance could be improved by adding 20 wt% SiC. In particular, the sample with 50 wt% Al₂O₃, 35 wt% Coal Series Kaolin (CSK), 15 wt% partially yttria?stabilized zirconia (PSZ), and 20 wt% SiC additional (denoted as sample A2) exhibited the best overall performance after firing at 1600 °C. Furthermore, the bending strength of sample A2 increased to 124.58 MPa, with an increasing rate of 13.63% after 30 thermal shock cycles. The increase in thermal conductivity and the formation of mullite were the factors behind the enhancement of thermal shock resistance. During the thermal cycles, the oxidation of SiC particles was favorable as it increased the microstructure densification and also facilitated the generation of mullite, which endowed the composite ceramics with a self?reinforcing performance.     

Effect of TGO thickness on the thermal barrier coatings life under thermal shock and thermal cycle loading

Effect of thermally grown oxide (TGO) thickness on thermal shock resistance of thermal barrier coatings (TBCs) and also their behavior under a cyclic loading (including aging at maximum temperature) was evaluated experimentally. In order to form different thicknesses of TGO, coated samples experience isothermal loading at 1070?°C for various periods of times. Heat-treated samples were heated to 1000?°C and cooled down rapidly in water from the substrate side using a mechanical fixture. The life of samples was investigated as a function of TGO thickness. Furthermore, by performing an experiment the simultaneous effect of the TGO growth and thermal expansion mismatch– on the failure of thermal barrier coatings was evaluated. The results demonstrated that the presence of TGO with a thickness of 2–3?µm has a positive effect on the resistance against thermal shock.     

用HGZ矾土刚玉与白刚玉制得的高热震稳定性刚玉砖的研究

用ＨＧＺ矾土刚玉与白刚玉共配制得了热震稳定性优异的刚玉砖。该砖热震稳定性的好坏与砖体结构有关。     

提高Si_3N_4结合SiC制品抗热震性的研究

分析了影响Ｓｉ３Ｎ４结合ＳｉＣ制品抗热震性的因素。研究结果表明，选择颗粒形状较好的原料、合理的颗粒级配及工艺配方是改善Ｓｉ３Ｎ４结合ＳｉＣ制品抗热震性能的根本途径，同时辅以预制裂纹，可有效地提高制品的抗热震性能。     

Fabrication and thermal shock behavior of periclase-forsterite aggregates with micro-nanometer dual-pore-size structures

To improve the service life of periclase-forsterite refractories, it is important to develop aggregates with high thermal shock resistance. In this study, periclase-forsterite aggregates with good resistance to thermal shock and micro-nanopores were prepared using high-silicon magnesite, silica, and silica sol. Microcracks were generated in the multiphase aggregates, which inhibited the continuous propagation of cracks during thermal shock through mismatched thermal expansion coefficients. Based on Hasselman's thermal shock stability factor, the reduction in the average thermal expansion coefficient and improved mechanical characteristics were critical factors in improving the thermal shock resistance of the multiphase aggregates. As a binder, silica sol provided nano-SiO₂ and superplasticity, which facilitated the formation of micro-nanopores and strengthened the combination of the various phases in the aggregates.     

Microstructure and thermal shock resistance of AlBOw- and BNw-whisker-modified thermal barrier coatings

To improve the crack propagation resistance of YSZ thermal barrier coatings during the thermal cycle, three kinds of thermal barrier coatings were prepared by atmospheric plasma spraying: YSZ, AlBOw-modified YSZ and BNW-modified YSZ. SEM, EDS and XRD were used to analyse the morphology, composition and phase composition of the sprayed powder and coating section. The phase structures of the YSZ, YSZ+AlBOw and YSZ+BNw coatings were t' phase. The cross-section of the coating presents a layered structure with pores inside. The porosity values of the YSZ, YSZ+AlBOw and YSZ+BNw coatings are 10.33%, 14.17% and 12.52%, respectively. The thermal shock resistance of three groups of coatings after 5 min at 1000 °C was analysed. The failure behaviour of the coatings after several thermal cycles was studied. The results show that the thermal shock resistance of the coatings with AlBOw is slightly lower than that of the YSZ coatings. The thermal shock resistance of the BNw coatings is 62.2% higher than that of the YSZ coatings. The whisker inhibits the crack propagation and prolongs the life of the coatings via crack deflection, whisker pull-out and whisker bridging.     

Thermal shock resistance of Al2O3/SiO2 composites by sol-gel

In this paper, the SiO₂ ceramic matrix composites were reinforced by the two-dimensional (2D) braided Al₂O₃ fibers by sol-gel. To develop the high performance aeroengine with excellent resistance to thermal shock for advanced aerospace application, two different thermal shock temperatures (1100?°C and 1300?°C) and three different thermal shock cycles (10, 20 and 30 cycles) were tested and compared in this paper; besides, the thermal shock resistance of Al₂O₃/SiO₂ composites was investigated in air. Our results suggested that, the flexural strength of the untreated composites was 78.157?MPa, while the residual strength of Al₂O₃/SiO₂ composites under diverse thermal shock cycles and temperatures had accounted for about 95% and 50% of the untreated composites, respectively. Meanwhile, the density and porosity of the composites were gradually increased with the increase in test temperature. Moreover, the changes in fracture morphology and micro-structural evolution of the composites were also observed. Our observations indicated that, the fracture morphology of the composites mainly exhibited ductile fracture at the thermal shock temperature of 1100?°C, whereas brittle fracture at the thermal shock temperature of 1300?°C. Additionally, Al₂O₃/SiO₂ composites belonged to the Oxide/Oxide CMCs, so no new phase was formed after thermal shock tests. Above all, findings of this paper showed that Al₂O₃/SiO₂ composites had displayed outstanding thermal shock resistance.