碳化硅陶瓷的性能与应用

详细的介绍了碳化硅原料的生产，碳化硅陶瓷的抗氧化、耐酸碱等化学性能，微观结构、色泽、热膨胀和导热系数、硬度、韧性等物理性能。并阐述了3种常用碳化硅陶瓷的致密化技术以及碳化硅在耐火材料、军事、航空航天、钢铁、电气和电工等工业部门的应用以及优越的性能和未来的应用前景。     

高温烟气过滤SiC多孔陶瓷孔隙率及烧结工艺研究

主要研究了碳化硅多孔陶瓷孔隙率的影响因素以及烧结工艺对碳化硅多孔陶瓷材料性能的影响。碳化硅多孔陶瓷孔隙率的大小直接影响其烟气的过滤效率,通过研究碳化硅骨料的粒径,碳化硅的含量以及造孔剂含量对孔隙率和孔径大小的影响因素,实现了对碳化硅多孔陶瓷的孔隙率大小的有效控制。同时对碳化硅多孔陶瓷的烧结工艺中的烧成气氛和烧成温度进行了研究,研究发现,在弱氧化气氛下,烧成温度为1330℃时制备的碳化硅多孔陶瓷具有较高的孔隙率和较为优异的力学性能。     

碳化硅陶瓷性能及研究进展

本文详细地介绍了碳化硅原料的生产,碳化硅陶瓷的化学性能以及物理性能等方面的特点,并阐述了几种常用的碳化硅陶瓷致密化技术以及在耐火材料、军事、航空航天、钢铁、电气和电工等工业部门的应用和应用前景。     

含堇青石涂层碳化硅网状多孔陶瓷的制备及燃烧特性

针对多孔介质高温燃烧用碳化硅多孔陶瓷因高温氧化导致抗热震性能以及辐射效率衰减等问题,首先采用有机泡沫浸渍法制备碳化硅素坯,经低温预烧、真空浸渍含Mg（OH）₂、单质Si和α-Al₂O₃浆料,经过原位反应烧结在碳化硅骨架表面构筑含堇青石红外辐射涂层的碳化硅多孔陶瓷。结果表明：真空浸渍浆料能在碳化硅骨架表面涂覆连续涂层的同时,能完全填充骨架的三角孔洞,经1 350℃烧结成功制备了具有堇青石涂层、碳化硅骨架中间层、堇青石填充层的3层结构碳化硅多孔陶瓷。3层结构的形成显著提高了碳化硅多孔陶瓷力学性能及抗热震性能以及高温抗湿氧化能力,碳化硅多孔陶瓷在1 350℃热处理后耐压强度达到1.18 MPa、残余强度保持率达67%;碳化硅多孔陶瓷中3层结构孔筋表面堇青石红外辐射涂层的形成,强化了碳化硅多孔介质燃烧器辐射换热过程和燃烧效率,将燃烧器表面温度提高约140℃,并显著降低了燃烧器中CO、NO_x等污染物的排放量。     

碳化硅陶瓷的液相烧结及其研究进展

本文对碳化硅液相烧结添加系统及其烧结机理作了论述。有氧化物参与的碳化硅的液相烧结可以降低碳化硅的烧结温度，促进碳化硅的致密化，提高碳化硅陶瓷的性能。沿晶断裂和穿晶断裂混合断裂机理是液相烧结碳化硅陶瓷强度和韧性提高的原因，表面强化和韧化可以进一步提高碳化硅陶瓷材料的性能。     

含水量对挤出成型碳化硅蜂窝陶瓷性能及结构的影响

以微米碳化硅为原料,采用挤出成型法制备碳化硅蜂窝陶瓷,利用排水法、扫描电子显微镜(SEM)和X-射线衍射(XRD)等测试技术分析了碳化硅蜂窝陶瓷的烧结性能、力学性能和显微结构,阐明泥料含水量对碳化硅蜂窝陶瓷的性能和结构的影响规律。研究表明:优化碳化硅泥料中的添加剂组成,能够挤压成型出碳化硅蜂窝素坯,无压烧结后得到碳化硅蜂窝陶瓷;随着含水量上升,碳化硅蜂窝陶瓷的相对密度先上升后下降,线收缩率则先下降后上升,抗弯强度则是先升高后降低,其值均在10 MPa以上;含水量不影响蜂窝陶瓷的物相组成。     

SiC电热陶瓷的组成与导电性能

通过铁系元素、稀土元素、铝元素和一些高价离子对碳化硅陶瓷导电性能的影响,研究了在还原气氛下碳化硅电热陶瓷的组成与导电性能的关系,从而获得了在小于１５００ ℃还原气氛下烧成,电阻率为０－０５ ～０－８５ 欧姆·米的碳化硅陶瓷电热材料。     

注浆成型碳化硅陶瓷材料成型工艺研究

碳化硅陶瓷材料是共价键极强的耐高温新型陶瓷，具备优良的综合物理化学性能，近年来已广泛应用于高新技术领域。本文采用注浆成型工艺制备高固含量低粘度碳化硅陶瓷，分析了注浆成型碳化硅陶瓷的工艺过程，粉体包覆改性，浆料制备，注浆素坯成型。为注浆成型碳化硅陶瓷相关研究提供一定的理论参考。     

烟气除尘用SiC多孔陶瓷孔径及孔隙率影响因素研究

本文主要研究了碳化硅多孔陶瓷孔隙率及孔径的影响因素。碳化硅多孔陶瓷孔隙率的大小直接影响其烟气的过滤效率,通过研究碳化硅骨料的粒径,碳化硅的含量以及造孔剂含量对孔隙率和孔径大小的影响因素,实现了对碳化硅多孔陶瓷的孔隙率大小的有效控制。为制备出高孔隙率,大孔径的碳化硅多孔陶瓷提供了保障。     

提高反应烧结碳化硅陶瓷性能的研究趋势

反应烧结碳化硅陶瓷是一种很有商业化前途的材料，但它的性能并不是很理想，从而限制了它的广泛应用。本文介绍了研究者在提高反应烧结碳化硅陶瓷性能方面所做的工作。     

Multiscale Modeling for Predicting the Mechanical Properties of Silicon Carbide Ceramics

Silicon carbide (SiC) is one of the advanced ceramics, which is widely used in industries due to its excellent mechanical properties. Understanding the relations between its microstructure and the mechanical properties is critical to adopting SiC ceramics in different applications. In this paper, a multiscale model incorporating a cohesive zone model is proposed to predict the mechanical properties of SiC ceramics. Interatomic potentials are developed using ab initio calculation to more accurately calculate the SiC behaviors in molecular dynamics modeling. The proposed multiscale model is used to predict the mechanical properties of SiC ceramics and their relations with the grain size distribution in the finite element framework. A good agreement is found between prediction results and experimental measurements. Successfully predicting its mechanical behaviors could help selection of parameters during processing of SiC ceramics under different conditions.     

Influence of domain orientation on the mechanical properties of lead zirconate titanate piezoelectric ceramics

The influence of domain orientation on the mechanical properties of lead zirconate titanate (PZT) piezoelectric ceramics has been investigated using un-poled and poled PZT ceramics. High mechanical properties, e.g., high elastic modulus and compressive strength, were obtained for the polarized PZT ceramics due to strain hardening caused by more severe domain switching during the loading process, while low mechanical properties for the un-poled ceramics. Fracture mechanics of the ceramics were influenced by the direction of the tetragonal lattice structure since cracks propagate along the long axis of the tetragonal structure (c-axis). Using X-ray diffraction and electron back scatter diffraction analysis, the domain switching characteristics could be clarified.     

刚玉瓷成形工艺与断裂韧性K_(IC)的关系

用不同的成形工艺制备氧化铝陶瓷,测量其抗弯强度、断裂韧性等主要力学性能;并讨论了不同的成形工艺与其主要力学性能尤其是断裂韧性K_(IC)的关系。     

Porous aluminum titanate‒strontium feldspar‒mullite fiber composite ceramics with enhanced pore structures and mechanical properties

This study demonstrates the pore structures and mechanical properties of porous aluminum titanate‒strontium feldspar‒mullite fiber (ASM) composite ceramics. Samples were prepared using two different processes. A traditional reactive sintering method, with Al₂O₃ and TiO₂ as raw materials, was used to prepare one group of samples, and an improved method, using aluminum titanate (AT) clinkers, was used to prepare another group of samples. The effects of the processes and raw materials on the pore structure and mechanical properties of the composite ceramics were investigated. The properties of the sintered porous ceramics, including the microstructure, density, porosity, pore size, and mechanical properties, were analyzed. After sintered at 1400 °C, the ASM ceramics that were prepared using the improved method had a porosity level of 70% and a pore size of 24 µm, which were twice that of the traditional ASM ceramics, while both samples had identical flexural strength values of 2.27 MPa. The improved process endowed the porous ASM ceramics with excellent pore structures and mechanical properties, promoting their potential use in filter applications.     

Microstructure and mechanical properties of in-situ grown mullite toughened 3Y-TZP zirconia ceramics fabricated by gelcasting

In-situ grown mullite toughened zirconia ceramics (mullite-zirconia ceramics) with excellent mechanical properties for potential applications in dental materials were fabricated by gelcasting combined with pressureless sintering. The effect of sintering temperature on the microstructure and mechanical properties of mullite-zirconia ceramics was investigated. The results indicated that the columnar mullite produced by reaction was evenly distributed in the zirconia matrix and the content and size of that increased with the increase of sintering temperature. Mullite-zirconia ceramics sintered at 1500 °C had the optimum content and size of the columnar mullite phase, generating the excellent mechanical properties (the bend strength of 890.4 MPa, the fracture toughness of 10.2 MPa.m^1/2, the Vickers hardness of 13.2 GPa and the highest densification). On the other hand, zirconia particles were evenly distributed inside the columnar mullite, which improved the mechanical properties of columnar mullite because of pinning effect. All of this clearly confirmed that zirconia grains strengthened columnar mullite, and thus the columnar mullite was more effective in enhancing the zirconia-based ceramics. Simultaneously, the residual alumina after reaction was distributed evenly in the form of particle, which improved the mechanical properties of the sample because of pinning effect. Overall, the synergistic effect of zirconia phase transformation toughening with mullite and alumina secondary toughening improved the mechanical properties of zirconia ceramics.     

From nature geometry to material design: Advanced fractal nature analysis for predicting experimental elastic properties

In this work, combined experimental and fractal nature analysis procedures are proposed in order to both model and design mechanical properties of porous ceramics. Several porous ceramics samples have been considered both from an in-situ experimental campaign and from the literature. Microstructural information concerning pore size distribution has been approximated by the Intermingled Fractal units (IFU) approach and effective mechanical properties are derived by a simple discrete model. The capability of the proposed methodology to reproduce high-scattered mechanical properties is fully shown and a comparison with classical bounds and estimates is also reported. Finally, the combined experimental, fractal nature analysis and homogenisation scheme is implemented as a design procedure for the technological production of advanced porous ceramics.     

添加剂TiO2和Cr2O3对复合陶瓷Mullite／ZrO2／Al2O3的影响

利用添加剂改善结构陶瓷材料的性能是一种较佳的方法,复合陶瓷mullite/ZrO_2/Al_2O_3具有较高的力学性能。试验证明:加入不同的添加剂对复合陶瓷有不同的影响,TiO_2会使材料的力学性能大幅度降低;Cr_2O_3会使材料的硬度显著提高。     

蓝色氧化锆陶瓷的研制

以微米或纳米氧化锆粉体为主原料,钒锆蓝色料或Co3O4为着色剂,添加适量烧结助剂制备蓝色氧化锆陶瓷。研究了氧化锆、助剂、着色剂等对蓝色氧化锆陶瓷颜色及性能的影响。结果表明:用纳米级ZrO2粉体为原料,钒锆蓝色料为着色剂,添加少量烧结助剂,可制得性能优良、颜色亮丽的蓝色氧化锆陶瓷;用纳米级ZrO2为原料,Co3O4为着色剂,添加少量烧结助剂,可制得性能优良、颜色亮丽的钴蓝色氧化锆陶瓷。     

Enhanced mechanical properties of 3D printed alumina ceramics by using sintering aids

Stereolithography based 3D printing provides an efficient pathway to fabricate alumina ceramics, and the exploration on the mechanical properties of 3D printed alumina ceramics is crucial to the development of 3D printing ceramic technology. However, alumina ceramics are difficult to sinter due to their high melting point. In this work, alumina ceramics were prepared via stereolithography based 3D printing technology, and the improvement in the mechanical properties was investigated based on the content, the type and the particle size of sintering aids (TiO₂, CaCO₃, and MgO). The flexural strength of the sintered ceramics increased greatly (from 139.2 MPa to 216.7 MPa) with the increase in TiO₂ content (from 0.5 wt% to 1.5 wt%), while significant anisotropy in mechanical properties (216.7 MPa in X-Z plane and 121.0 MPa in X–Y plane) was observed for the ceramics with the addition of 1.5 wt TiO₂. The shrinkage and flexural strength of the ceramics decreased with the increase in CaCO₃ content due to the formation of elongated grains, which led to the formation of large-sized residual pores in the ceramics. The addition of MgO help decrease the anisotropic differences in shrinkage and flexural strength of the sintered ceramics due to the formation of regularly shaped grains. This work provides guidance on the adjustment in flexural strength, shrinkage, and anisotropic behavior of 3D printed alumina ceramics, and provides new methods for the fabrication of 3D printed alumina ceramics with superior mechanical properties.     

Effect of temperature on the structure and mechanical properties of SiC–TiB2 composite ceramics by solid-phase spark plasma sintering

SiC composite ceramics have good mechanical properties. In this study, the effect of temperature on the microstructure and mechanical properties of SiC–TiB₂ composite ceramics by solid-phase spark plasma sintering (SPS) was investigated. SiC–TiB₂ composite ceramics were prepared by SPS method with graphite powder as sintering additive and kept at 1700 °C, 1750 °C, 1800 °C and 50 MPa for 10min.The experimental results show that the proper TiB₂ addition can obviously increase the mechanical properties of SiC–TiB₂ composite ceramics. Higher sintering temperature results in the aggregation and growth of second-phase TiB₂ grains, which decreases the mechanical properties of SiC–TiB₂ composite ceramics. Good mechanical properties were obtained at 1750 °C, with a density of 97.3%, Vickers hardness of 26.68 GPa, bending strength of 380 MPa and fracture toughness of 5.16 MPa m^1/2.