氧化锆复合氮化硅陶瓷

分析了二氧化锆的性质及氧空位对二氧化锆相变的影响,讨论了二氧化锆韧化氮化硅陶瓷的影响因素,提出了二氧化锆韧化氮化硅陶瓷时避免氮化锆生成、促进复相氮化硅陶瓷烧结的途径。     

国外特种陶瓷实用技术资料

339瓷器烧成用碳化硅耐火材料340带导电涂层的二氧化锆固体电解质341利用钇精矿制取二氧化锆固体电解质342部分稳定二氧化锆陶瓷343用水玻璃浸渍法制取免烧石英陶瓷344复合陶瓷材料345二氧化锆陶瓷的制作方法对其机械强度的影响346反应结合氮化硅基结构陶瓷材料347用大阳能炉熔制的镁铝尖晶石陶瓷348非塑性刚玉坯料的成形问题349反应烧结碳化氮化物复合材料350高绝热性轻质刚玉耐火材料351氧化钙的烧结352不收缩石英陶瓷353各种粘合剂对氧化铝纤维绝热制品性能的影响354粒状填料基绝热材料的制得355亚铬酸忆基陶瓷的功能耐热性356部分稳定Z…     

借鉴日本专利技术，促进国内高导热氮化硅基片产业化

随着半导体集成模块发热量巨增,市场急需高导热陶瓷基片,介绍了高导热陶瓷基片的种类、特点和市场主要供应商,明确了氮化硅陶瓷基片具有高热导、高强高韧、热膨胀适应性良好等特点,以其突出的综合性能适应于第三代半导体芯片的发展方向,针对我国氮化硅基片仍未产业化,本文总结了全球主要供应商日本企业在华专利技术,为我国氮化硅基片产业化提供技术情报和专利预警。     

关于由Si3N4和ZrO2制造的陶瓷的抗裂性评定问题

研究了应用于广泛温度范围内的氮化硅及二氧化锆陶瓷的机械性状。着重探索了在周围介质条件下的抗裂性。查明，认为采用维氏硬度试验压头压痕法对试样进行试验的结果是可信的。根据分析结果，对材料的组织断面做了研究，并参照了二氧化锆模拟材料的试验数据。     

氮化硅陶瓷的烧结

氮化硅陶瓷广泛用作高温结构材料,是很有前途的陶瓷材料之一。本文研究了氮化硅陶瓷烧结动力学,分析了影响氮化硅陶瓷烧结的因素,为氮化硅陶瓷烧结提供了依据     

烧结助剂对氮化硅陶瓷显微结构和性能的影响

氮化硅中氮原子和硅原子的自扩散系数很低，致密化所必需的扩散速度和烧结驱动力都很小，在烧结过程中需采用烧结助剂。烧结助剂是影响氮化硅陶瓷的显微结构和性能的关键因素之一。有效的烧结助剂不但可以改善氮化硅陶瓷的显微结构，而且可以提高氮化硅陶瓷的高温性能和抗氧化性能。     

Si3N4及其复合材料强韧化研究进展

简述了氮化硅陶瓷的结构、性能和制备工艺，并分别通过自增韧补强、纤维／晶须强韧化、层状结构强韧化、相变强韧化以及颗粒弥散强韧化等方法对氮化硅陶瓷的强韧化研究进行了分类叙述。     

多孔氮化硅陶瓷的研究进展

综述了多孔氮化硅陶瓷材料的国内外研究现状和进展,介绍了多孔氮化硅陶瓷的主要制备方法,分析了微观组织对多孔氮化硅陶瓷力学性能的影响,并与其他多孔陶瓷进行了性能比较,最后展望了多孔氮化硅陶瓷的发展前景.     

振荡压力对高性能氮化硅陶瓷烧结致密化的影响EI北大核心CSCD

采用新型振荡压力烧结技术制备高性能氮化硅陶瓷,并对比热压烧结技术,研究了不同工艺下氮化硅陶瓷的致密度、物相、晶粒尺寸、微观形貌及力学性能变化规律,分析了振荡压力对氮化硅陶瓷的致密化作用.结果表明:振荡压力烧结工艺下氮化硅陶瓷实现了α相到β相的物相完全转变,相对密度达到了99.82%;对比热压烧结工艺,振荡压力作用下氮化硅陶瓷的晶粒尺寸明显增加,晶粒平均长径比由3.79增加到4.86,弯曲强度、硬度及断裂韧性分别提高到1333 MPa、16.2 GPa、12.1 MPa·m^(1/2),断裂表面能也明显提高.OPS试样晶粒表面观察到了明显的形变条纹和位错运动区域.振荡压力的引入提高了致密化速率和晶粒的生长驱动力,且能够促进氮化硅在致密化过程中塑性形变的产生,有效加快了烧结致密化进程.     

振荡压力对高性能氮化硅陶瓷烧结致密化的影响

采用新型振荡压力烧结技术制备高性能氮化硅陶瓷,并对比热压烧结技术,研究了不同工艺下氮化硅陶瓷的致密度、物相、晶粒尺寸、微观形貌及力学性能变化规律,分析了振荡压力对氮化硅陶瓷的致密化作用。结果表明:振荡压力烧结工艺下氮化硅陶瓷实现了α相到β相的物相完全转变,相对密度达到了99.82%;对比热压烧结工艺,振荡压力作用下氮化硅陶瓷的晶粒尺寸明显增加,晶粒平均长径比由3.79增加到4.86,弯曲强度、硬度及断裂韧性分别提高到1 333 MPa、16.2 GPa、12.1 MPa·m~(1/2),断裂表面能也明显提高。OPS试样晶粒表面观察到了明显的形变条纹和位错运动区域。振荡压力的引入提高了致密化速率和晶粒的生长驱动力,且能够促进氮化硅在致密化过程中塑性形变的产生,有效加快了烧结致密化进程。     

Problem of evaluating the crack resistance in ceramics of Si3N4 and ZrO2

The mechanical behavior of silicon nitride and zirconium dioxide ceramics is investigated in a wide temperature range. Much attention is paid to crack resistance under the conditions of the ambient. Data obtained by different methods used for evaluating crack resistance are analyzed, and it is shown that the best results have been obtained in tests in which the concentrator was an indentation of a Vickers pyramid. The analysis was conducted using fractographic investigations of the materials and data of tests of a model material of zirconium dioxide.Translated from Ogneupory, No. 1, pp. 21 – 26, January, 1996.     

氮化硅陶瓷韧化的研究与进展

本文阐述了氮化硅陶瓷的增韧补强的研究与进展,对氮化硅的几种常见增韧补强的途径如弥散增韧、纤维增韧、相变增韧、自增韧、层状复合增韧作了评述,指出了目前进行氮化硅陶瓷的增韧的途径与方向。     

Thermal decomposition of carbon-rich polymer-derived silicon carbonitrides leading to ceramics with high specific surface area and tunable micro- and mesoporosity

Herein we report on the thermal decomposition of SiCN polymer-derived ceramics leading to materials with high specific surface area and defined pore sizes. The ceramics were obtained by means of pyrolysis of a carbon-rich poly(diphenylsilylcarbodiimide) precursor and by varying the thermolysis parameters, namely temperature, annealing time and using additional annealing steps. The thermal decomposition of SiCN ceramics is correlated with the carbothermal reaction of amorphous silicon nitride phase with excess carbon and this detrimental event leads to high specific surface area up to 568 m² g⁻¹ and micro- and mesopores formation in these materials. High-resolution TEM investigations have confirmed that the pores are embedded only in the carbon phase. Moreover, the relationship between the pore sizes and the organization of free carbon phase is discussed.     

烧结助剂对多孔氮化硅陶瓷的力学性能及介电性能的影响

通过添加烧结助剂,采用常压烧结工艺制备出不同气孔率(19%～54%)的氮化硅陶瓷.采用Archimedes法、三点弯曲法和Vickers硬度测试法测量了材料的密度、气孔率、抗弯强度及硬度.用X射线衍射及扫描电镜检测了相组成和显微结构.用谐振腔法测试了氮化硅陶瓷在10.2 GHz的介电特性.结果表明:材料具有优良的介电性能.随着烧结助剂的减少,样品中气孔率增加,力学性能有所下降,介电常数和介电损耗降低.添加Lu2O3所制备的氮化硅陶瓷的力学性能和介电性能优于添加Eu2O3或Y2O3制备的氮化硅陶瓷.当气孔率高于50%时,多孔氮化硅陶瓷(添加入5%的Y2O3或Lu2O3,或Eu2O3,质量分数)的抗弯强度可达170 MPa,介电常数为3.0～3.2,介电损耗为0.000 6～0.002.     

Effect of the thermal treatment on the phase composition of the surface of coatings based on Si–B–ZrB<Subscript>2</Subscript> and modified with ZrO<Subscript>2</Subscript> fibers

Coatings on graphite that are stable to oxidation and based on the silicon–boron–zirconium boride composite containing from 5 to 50% of fibrous zirconium dioxide as a modifying dopant have been produced by the suspension–annealing method. A nonporous layer is formed at the zirconium dioxide content ranging from 5 to 15%, while a porous layer is formed at its 50% content. A glass-forming melt, as well as zirconium dioxide and silicate, is formed during thermal treatment as a result of the chemical reactions with the oxygen in air. The zirconium silicate content increases, along with the modifier’s concentration and temperature.     

Porous Silicon Nitride Ceramics Prepared by Reduction–Nitridation of Silica

A new method for preparing porous silicon nitride ceramics with high porosity had been developed by carbothermal reduction of die-pressed green bodies composed of silicon dioxide, carbon, sintering additives, and seeds. The resultant porous silicon nitride ceramics showed fine microstructure and uniform pore structure. The influence of SiO₂ particle size and sintering process (sintering temperature and retaining time) on the microstructure of sintering bodies was analyzed. X-ray diffractometry demonstrated the formation of single-phase β-Si₃N₄ via the reaction between silicon dioxide and carbon at high temperature. SEM analysis showed that pores were formed by the banding up of rod-like β-Si₃N₄ grains. Porous Si₃N₄ ceramics with a porosity of 70–75%, and a strength of 5–8 MPa, were obtained.     

氮化硅陶瓷牙科修复材料研究进展

氮化硅具有比氧化铝、氧化锆等牙科陶瓷修复材料更好的力学性能、化学稳定性和生物相容性,已经用于生物骨科修复.近年来陆续有学者将氮化硅陶瓷引入到牙科修复领域,文章在介绍氮化硅陶瓷性能特点的基础上,综述了氮化硅陶瓷牙科种植体、氮化硅桩核冠及氮化硅饰面瓷的研究进展,并展望了氮化硅在牙科修复领域的未来研究方向.     

Microstructure control and mechanical properties of porous silicon nitride ceramics

Porous silicon nitride ceramics with a fibrous interlocking microstructure were synthesized by carbothermal nitridation of silicon dioxide. The influences of different starting powders on microstructure and mechanical properties of the samples were studied. The results showed that the microstructure and mechanical properties of porous silicon nitride ceramics depended mostly on the size of starting powders. The formation of single-phase β-Si₃N₄ and the microstructure of the samples were demonstrated by XRD and SEM, respectively. The resultant porous Si₃N₄ ceramics with a porosity of 71% showed a relative higher flexural strength of 24 MPa.     

氮化硅陶瓷在四大领域的研究及应用进展

氮化硅陶瓷不仅具有较高的力学性能还具有良好的透波性能、导热性能以及生物相容性能,是公认的综合性能最优的陶瓷材料。作为轴承球的致密氮化硅陶瓷广泛应用在机械领域;作为透波材料的多孔氮化硅陶瓷广泛应用在航空航天领域;随着对氮化硅陶瓷材料的深入研究,其在导热性和生物相容性方面的优异特性逐渐被科研工作者认识并得到开发和应用。本文详细阐述了氮化硅粉体的制备方法,并综述了氮化硅陶瓷作为结构陶瓷在机械领域和航空航天领域的研究进展,此外还介绍了其作为功能陶瓷在半导体领域、生物制药领域的研究和应用现状,最后对其未来发展进行了展望。     

New method of free silicon determination in pressureless sintered silicon nitride by Raman spectroscopy and XRD

Formation of silicon affects different physical properties of silicon nitride ceramics. Decomposition of Si₃N₄ and formation of free Si are highly important processes and depend on many factors. The proposed method of combined nano-Raman spectroscopy and X-ray diffraction (XRD) allows quantitative analysis of Si in silicon nitride. Raman spectroscopy enables the determination of atomic bonds and rapid and easy identification of free silicon. Further analysis of the crystalline phases by XRD enables the calculation of the amount of free silicon. The proposed complex method allows the characterization of such complicated processes as silicon nitride decomposition, microstructure formation and, in particular, the formation of the nanoscale grain boundary phase because Si nanosized precipitates are the nucleants of secondary phases during crystallization. Strong 522.8 cm⁻¹ mode and 943.1–984.3 cm⁻¹ transverse optical modes of free Si were clearly observed in the investigated silicon nitride that was subjected to pressureless sintering at 1800 °C. Reported ceramics demonstrated typical microstructures with elongated grains and relatively high microhardness and Young's modulus. It was shown that the aspect ratio depended linearly on the microhardness and Young's modulus. High values of the Young's modulus (more than 290 GPa) and microhardness (more than 1800 HV) were shown for reported silicon nitride produced by hot pressing and pressureless sintering via cold isostatic pressing with a higher quantity of sintering agent. The features of molecular structure of the reported Si₃N₄ ceramics were clearly described and discussed in detail and were found to be in good agreement with the microstructure and phase composition of these ceramics.