微波烧结工艺制备陶瓷材料的研究现状

微波烧结作为一种陶瓷制备工艺,因其与传统烧结工艺相比体现出快速高效、节能环保等一系列优点而备受关注.主要介绍了采用微波烧结工艺制备陶瓷材料及陶瓷基复合材料的特点；在先驱体裂解、粉末烧结制备陶瓷材料方面对微波烧结工艺与传统烧结工艺进行比较,表明微波烧结工艺是一种极具潜力的技术；最后提出微波烧结工艺在未来发展过程中亟待解决的若干问题.     

微波加热制备特种陶瓷材料研究进展

特种陶瓷广泛应用于航天航空、电子信息、新能源、机械、化工等新兴工业领域,其高温制备过程仍以传统燃气窑炉和电加热炉为主;碳排放高、能耗大,节能减排形势严峻。当前,我国面临实现“双碳”目标的巨大压力,研究推广清洁高效的加热技术迫在眉睫。微波加热是利用材料自身对微波进行吸收,将电磁能转化为热能,能量的转移发生在分子水平上,通过这种方式,加热在整个材料内外同时产生,整个材料体系中的温度梯度非常低。除体积加热外,选择性加热、功率再分配、热剧变以及微波等离子效应等也是微波烧结的显著特征。微波加热具有节能环保、改善制品性能、减少燃烧碳排放等优点,国内外有许多关于微波合成各种氧化物、碳化物、氮化物陶瓷粉体和微波烧结陶瓷复合材料的报道。本文首先对微波和微波混合烧结的基本理论进行综述,然后介绍了微波加热制备陶瓷粉体与微波烧结制备陶瓷材料的最新研究进展,最后总结了微波加热在陶瓷工程制品烧结中的一些研究成果,体现出微波烧结的优越性,并提出了微波烧结制备特种陶瓷的关键问题和今后的发展方向。     

添加V2O5对Ba(Mg1/3Ta2/3)O3烧结及微波介电性能的影响

本工作就添加V2O5对Ba（Mg1／3Ta2／3）O3烧结性及微波介电性能的影响进行了研究和讨论．实验结果发现，添加少量V2O5能明显改善BMT陶瓷的烧结性，当V2O5的添加量为0．1mol％时，烧结体密度可达理论密度的98％同时较纯BMT陶瓷烧结温度降低150℃左右．此时样品仍具有较高的微波介电性能：Q·f＝62450GHz；εγ＝25．     

微波烧结技术的研究进展

微波烧结不同于传统烧结,是一种全新的烧结技术,本文介绍了微波烧结的基本原理、特点,全面综述了微波烧结技术的研究现状,指出了其存在的不足,并展望了微波烧结技术的发展趋势。     

先进陶瓷微波烧结技术的研究与产业化应用

微波烧结技术因其在陶瓷材料制备领域的突出优势,被誉为"21世纪新一代烧结技术"。本文介绍了微波烧结的原理与装置结构,列举了微波烧结与传统烧结工艺相比的特点以及影响微波烧结效果的因素,指出了微波烧结技术亟待解决的问题,综述了微波烧结工艺的应用及产业化现状。     

金属材料微波烧结技术的研究进展

金属及其合金、复合材料的快速烧结一直都是金属材料领域的难题.微波烧结技术因具有体积加热、选择性加热以及非热效应等特性,相比于传统烧结工艺能够显著降低烧结温度、缩短烧结周期,在制备结构均匀、晶粒细小、综合力学性能优异的金属材料方面拥有巨大的潜力.本文介绍了金属材料微波烧结过程中热效应(介电损耗、电导损耗与磁损耗)与非热效应(放电效应与磁效应)对烧结制品的影响,综述了近几年国内外微波烧结金属及其合金、复合材料方面的主要研究进展,对微波烧结过程中存在的问题进行了分析,并对后续金属材料微波烧结技术的研究方向进行了展望,以期为后续研究者提供有力参考.     

微波等离子体烧结陶瓷的研究进展

从微波等离子体的特点、其应用于烧结陶瓷的特点及适用范围、主要烧结过程和实验装置等几个方面介绍了微波等离子体这一新型烧结技术.同时综述了近几年来微波等离子体新型烧结技术在陶瓷烧结方面的最新的应用研究进展.     

β－Sialon陶瓷的微波烧结研究

微波加热具有极快的加热和烧结速度，并从根本上不同于常规加热．利用微波能在高温烧结陶瓷是近年来迅速发展的一门新技术．本文利用自行研制的ＴＥ＿１０３单模腔微波烧结系统对没加添加剂的自蔓延高温合成的β－Ｓｉａｌｏｎ粉的微波加热特征进行了研究．通过选择适当的保温方式，快速加热至１６５０℃，有着适当的保温时间可获得９７．５％ＴＤ的β－Ｓｉａｌｏｎ陶瓷，与常规无压烧结（１８５０℃）相比显示了更高的密度，更均匀的微观结构和力学性能．     

微波低温烧结制备氮化铝透明陶瓷

微波烧结(Microwave Sintering)是一种新型、高效的烧结技术, 具有传统烧结技术无可比拟的优越性. 本文在不添加任何烧结助剂的前提下, 采用高纯微米级氮化铝(AlN)粉, 在1700℃/2h的微波低温烧结工艺条件下制备出透明度较高的AlN透明陶瓷. 分析结果表明, 采用微波低温烧结工艺制备的AlN透明陶瓷晶粒尺寸细小(<10μm), 晶粒发育完善且分布均匀, 晶界平直光滑且无第二相分布, 从而证明用微波烧结可以实现AlN透明陶瓷的低温烧结.     

β—Sialon陶瓷的微波烧结研究

微波加热具有极快的加热和烧结速度，并从根本上不同于常规加热，利用微波高温烧结陶瓷是近年来迅速发展的一门新技术，本文利用自行研制的ＴＥ１０３单模腔微波烧地没加添加剂的自蔓 β－Ｓｉａｌｏｎ粉的微波加热特征进行了研究，通过选择适当的保浊 速加热至１６５０℃，有着适当的保温时间可获得９７．５％ＴＤ的β－Ｓｉａｌｏｎ陶瓷，与常规无压烧结（１８５０℃）相比显示了更高的密度，更均匀的微观结构和力学性能。     

Step Sintering of Microwave Heating and Microwave Plasma Heating for Alumina Ceramics

1.IntroductionNumerousstudieshaveshownthatmicrowavesin-teringofceramicshassomeadvantagesoverconven-tionalsinteringprocess,suchassavingsinenergyandprocessingtime,volumetricandrapidheating,lowerdensificationtemperature,uniformmicrostruc-tureofsinteredceramics,improvedmaterialsperfor-mance,productionofnewmaterialsandmicrostruc-tureetc..Basedontheformofmicrowaveenergyused,microwavesinteringcanbebasicallydividedintomicrowaveheatingsintering,microwaveplasmaheatingsinteringandstepsioteringwhichcombin…     

陶瓷材料的微波—等离子体分步烧结

提出微波加热和微波等离子加热分步烧结方法。在这一方法中,把微波加热和微波等离子和热有机地结合到一个微波应用器内,等离子的激励无需在负压下进行;烧结分两步完成。先用微波直接将烧结件加热到一定温度,再用微波等离子体继续加热到烧结度。     

Assessment of Microwave Heating for Sintering of Al/SiC and for in‐situ Synthesis of TiC

This work describes sintering of SiC‐reinforced Al‐matrix composites and in‐situ synthesis of TiC in a powder mixture of Ti and C. In the first case, microwave energy is absorbed by SiC grains, heating the metal matrix to sintering and even melting temperature. The composite is processed at <1 kW microwave power. Microwave absorption and the heating rate increase with decreasing SiC particle size. Composites with high SiC content (70 vol.‐%) are processed at 650 °C/1 h in the microwave furnace, whereas conventional resistive heating at the same temperature did not allow sintering of the sample. In the second case, radiative energy allowed the heating of Ti/C samples up to 950 °C, and microwave assistance enhanced the reaction sintering of Ti/C powder mixtures forming TiC at the border of the Ti particles. The results are compared with conventional processing. Optical images and XRD patterns confirmed the formation of TiC for both techniques.     

Prospects of microwave processing: An overview

Microwave processing has been emerging as an innovative sintering method for many traditional ceramics, advanced ceramics, specialty ceramics and ceramic composites as well as polymer and polymer composites. Development of functionally gradient materials: joining; melting; fibre drawing; reaction synthesis of ceramics; synthesis of ceramic powder, phosphor materials, whiskers, microtubes and nanotubes; sintering of zinc oxide varistors; glazing of coating surface and coating development have been performed using microwave heating. In addition, microwave energy is being explored for the sintering of metal powders also. Ceramic and metal nanopowders have been sintered in microwave. Furthermore, initiatives have been taken to process the amorphous materials (e.g. glass) by microwave heating. Besides this, attempt has been made to study the heating behaviour of materials in the electric and magnetic fields at microwave frequencies. The research is now focused on the use of microwave processing for industrial applications.     

Prospects of microwave processing: An overview

Microwave processing has been emerging as an innovative sintering method for many traditional ceramics, advanced ceramics, specialty ceramics and ceramic composites as well as polymer and polymer composites. Development of functionally gradient materials, joining, melting, fibre drawing, reaction synthesis of ceramics, synthesis of ceramic powder, phosphor materials, whiskers, microtubes and nanotubes, sintering of zinc oxide varistors, glazing of coating surface and coating development have been performed using microwave heating. In addition, microwave energy is being explored for the sintering of metal powders also. Ceramic and metal nanopowders have been sintered in microwave. Furthermore, initiatives have been taken to process the amorphous materials (e.g. glass) by microwave heating. Besides this, an attempt has been made to study the heating behaviour of materials in the electric and magnetic fields at microwave frequencies. The research is now focused on the use of microwave processing for industrial applications.     

Low-temperature microwave sintering of TiN–SiC nanocomposites

Densification kinetics study during microwave sintering of titanium nitride-based nanocomposite has been conducted. A series of TiN–SiC compositions with 1, 3, 5 wt% of silicon carbide were microwave sintered at relatively low sintering temperatures (900–1,300 °C) for 0–30 min. The SiC content influenced on heating uniformity and final density and grain-size achieved. Densification process during microwave sintering obeyed the mechanism of grain-boundary diffusion with activation energy of 235 kJ mol⁻¹. Microwave sintering resulted in fine microstructure (~300 nm) and hence high values of micro hardness (~20 GPa).     

Effect of composition on the enhanced microwave sintering of alumina-based ceramic composites

A series of comparative experiments were performed in which a number of alumina-zirconia compositions were sintered in both microwave and conventional furnaces, using identical heating profiles. Measurement of sample end-point densities showed an enhancement of the sintering process associated with the use of microwave heating for all compositions studied. The associated microstructures examined using scanning electron microscopy showed slightly larger grain sizes for the microwave-sintered compacts, as would be expected from their higher densities. The design of a high-temperature sintering dilatometer has allowed continuousin situ monitoring of the densification process in both the microwave and conventional environment. Data obtained in this way have shown that there is an effect of composition on microwave densification. This appears to be related to the increased lossiness of the composite, (increased zirconia content), rather than the effect of zirconia as a sintering aid. In addition the dilatometer results suggest that the microwave enhancement of the sintering process may be due to a reduction in the activation energy for grain-boundary diffusion.Electricity Association Technology Ltd. Registered Office: 30 Millbank, London SW1P 4RD.     

Development of a microwave sintered TiO2 reinforced Sn–0.7wt%Cu–0.05wt%Ni alloy

The use of reinforcing nano-size ceramic particulates is a promising method to improve the mechanical and thermal properties of lead-free solder materials. In addition, advanced fabrication processes routes such as microwave sintering powder metallurgy (PM) enhance properties in the fabrication of composite solders. To elucidate the mechanisms underlying the improvements in mechanical and thermal properties, Sn–Cu–Ni with TiO₂ nano-composite additions, fabricated via a microwave sintering PM method, were investigated using state-of-the-art characterization techniques. Synchrotron micro-X-ray fluorescence (XRF) results detected trace Ti in the solder matrix. This was consistent with X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM) results which indicated that nano crystals were within the Sn matrix. It is possible these nano crystal form due to the migration of Ti during the rapid high energy microwave heating. A hypothesis of improved thermal and mechanical properties of nano-composite solders is discussed based on the results and the microwave sintering PM route was discussed as a promising method for next generation lead-free solder processing.     

Ce-Y-ZTA 复相陶瓷的微波烧结

系统研究了Ce-Y-ZTA 复相陶瓷批量试样在2. 45GHz, 功率0. 5～ 5kW 连续可调的矩形多模腔内的微波烧结过程及材料性能。实验表明: 通过合理的保温结构和工艺控制, 可实现高稳定性和重复性的微波快速烧结。相对密度达到99%TD。与常规烧结相比, 微波烧结过程只需约2小时, 致密化温度降低50～ 100℃。烧结后材料具有晶粒尺寸细小、均匀的显微结构, 弯曲强度由600M Pa 提高至670M Pa, 同时获得较高断裂韧性值。