共查询到20条相似文献,搜索用时 31 毫秒
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将316L不锈钢粉、造孔剂(尿素颗粒)和粘结剂(聚乙烯醇溶液)进行混合,压坯后采用高温真空烧结制备出多孔不锈钢。利用真空浸渍法计算不同烧结温度下试样的孔隙率,在金相显微镜下观察试样的孔径分布及孔大小等,采用压汞法测试不同烧结温度下的最大孔径及其渗透性能。结果表明,烧结温度在1200℃时可获得小孔径分布均匀、孔隙贯通性良好的多孔结构;但烧结温度超过1200℃,烧结试样发生孔径的收缩和变形,使得孔隙率减小,多孔材料的渗透性能降低。 相似文献
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利用碳还原法,研究了在放电等离子烧结(SPS)技术下反应制得孔隙率较高的多孔ZrB2基陶瓷的烧结制度,制备了不同孔隙率的ZrB2基多孔陶瓷.并对其孔隙率、物相组成、微观结构和力学性能进行了分析和评价.结果表明:得到高孔隙率的ZrB2基多孔陶瓷的烧结工艺为,室温~1400℃升温速率100℃/min,1400~1750℃之间50℃/min,中间保温温度1700℃,最终烧结温度1800℃,保温3min.用该烧结制度通过调节反应得到的ZrB2的量在0.11到0.35范围内可达到孔隙可控,微观结构较均匀,随着孔隙率的增加,热导率显著降低. 相似文献
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采用亚微米WC粉和微米Co粉混合粉末作为原料,利用高能球磨与放电等离子烧结(SPS)技术制备超细晶WC-10Co硬质合金.研究表明,球磨后直接烧结时,当温度由1150℃增加到1200℃,试样的晶粒尺寸和硬度没有明显变化(平均晶粒尺寸约250nm),但致密度提高至98.6%,横向断裂强度由1045MPa提高到1819MPa.当对球磨后的混合粉末进行900℃真空处理后,在较低温度烧结的条件下试样的致密度则高达99%,且横向断裂强度与未处理粉末在相同工艺下烧结获得提高. 相似文献
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放电等离子超快速烧结氧化铝力学性能和显微结构研究 总被引:2,自引:0,他引:2
本文介绍用放电等离子超快速烧结方法制备的氧化铝陶瓷的力学性能和显微结构特征.超快速烧结的升温速率为600℃/min,在烧结温度不保温,迅即在3min内冷却至600℃以下.与保温时间为2h的无压烧结相比,可降低烧结温度和提高样品密度.力学性能研究结果表明,用放电等离子超快速烧结方法制备的纯氧化铝陶瓷的抗弯强度高达800MPa以上,比通常氧化铝陶瓷的抗弯强度高出一倍.用SEM研究了在不同温度下超快速烧结的纯氧化铝陶瓷的显微结构特征. 相似文献
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以Ta粉、Al粉和炭黑粉为原料,利用自蔓延高温合成、无压烧结和放电等离子烧结组合工艺,成功制备了高纯Ta2AlC块体陶瓷,研究了放电等离子烧结制备的Ta2AlC块体的微观形貌与性能.制备的Ta2AlC块体的硬度、弯曲强度和断裂韧性分别为5.6 GPa、510 MPa和6.16 MPa·m1/2.放电等离子烧结工艺升温速率快、烧结时间短、制备的陶瓷晶粒细小,细晶强化效果明显,使得块体陶瓷有明显的高硬度和强度.Ta2AlC陶瓷在700~900℃空气中恒温氧化时,表现出线性氧化动力学特征,氧化层的主要成分从700℃的Ta2O5逐渐转变成800~900℃时的Ta2O5和AlTaO4. 相似文献
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放电等离子超快速烧结氧化物陶瓷 总被引:15,自引:6,他引:15
本文介绍一种氧化物陶瓷超快速烧结的新方法.用放电等离子烧结的方法对Al2O3、Y-TZP、YAG、Al2O3-ZrO22和莫来石等各种氧化物粉体进行了超快速烧结,采用2~3min升温到1200℃以上,不保温或保温2min,然后迅即在3min之内冷却至600℃以下的烧结温度,得到了直径为20mm的晶粒细、致密度高、力学性能好的烧结样品.对用化学共沉淀法自制的20mol%Al2O3-ZrO2(3Y)纳米粉体分别在1170~1500℃之间的7个不同温度下进行放电等离子烧结,升温速率为200℃/min,保温2min后;迅即在3min之内强制冷却至600℃以下.1350℃以上烧结得到的样品密度已接近理论密度,1250℃以上烧结得到的样品的断裂韧性K1c都大于6MPa·m1/2放电等离子超快速反应烧结所得到的ZrO2-莫来石复相陶瓷致密度高、力学性能好,ZrO2晶粒在莫来石基体中分布均匀,XRD结果表明,在1530℃烧结的样品中,已找不到ZrsiO4痕迹,说明在如此快速的烧结条件下;反应烧结已经可以完成. 相似文献
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采用放电等离子烧结(SPS)法制备长石类牙科陶瓷,研究了烧结工艺对其性能的影响。结果表明,在压力30MPa,烧结升温速度100℃/min,烧结温度1120-1300℃下,SPS能够实现长石瓷的高密度烧结,断裂韧性达到1.4MPa·m1/2以上。 相似文献
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机械合金化和放电等离子烧结制备Y3Al5O12陶瓷 总被引:2,自引:0,他引:2
采用机械合金化和放电等离子烧结制备YAG陶瓷,研究了球磨时间对原料颗粒大小和烧结合成YAG纯度的影响,并利用x射线衍射(XRD)、扫描电镜(SEM)等手段对反应过程及产物形貌和物相进行了分析.研究结果表明,机械合金化Y2O3和Al2O3粉体,可明显细化氧化物颗粒,球磨20h后,Y2O3和Al2O3晶粒大小约为34nm和32nm.球磨处理的Y2O3和Al2O3粉体具有很高的活性,促进放电等离子烧结低温反应合成和获得致密的YAG.对球磨20h的粉体在不同温度进行放电等离子烧结,在1200℃即可获得纯YAG陶瓷,在1500℃烧结,可得到相对密度为99.5%的YAG陶瓷.1500℃烧结的块体在可见光范围内透过率为13.8%. 相似文献
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通过化学沉淀法引入烧结助剂Y3+、La3+和Mg2+, 采用真空烧结工艺制备了半透明Al2O3陶瓷, 并研究了烧结助剂对烧结材料的微观结构、相对密度和透光率的影响。结果表明: 引入的烧结助剂能均匀分散在合成的半透明Al2O3陶瓷中。烧结助剂的最佳引入量为Mg2+(0.15wt%)、Y3+(0.05wt%)和La3+(0.05wt%), 对应的试样在350~800 nm的波长范围内显示出的最高的总透光率(TFT)高于80%。此外, Y3+的掺杂可以促进晶粒生长, 降低孔隙率, 从而提高半透明Al2O3陶瓷的透光率。 相似文献
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应用放电等离子烧结技术(SPS)制备新型SPS NdFeB磁体.利用扫描电子显微镜(SEM)观察磁体的显微组织,利用B-H回线仪测量磁体磁性能,利用阿基米德法测量样品密度.系统研究了稀土含量不同的两种NdFeB磁体的烧结特征.结果表明,SPS NdFeB磁体的烧结特征与传统烧结方式的特征不同,且与样品稀土含量密切相关;... 相似文献
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Shufan Wang Tarini Prasad Mishra Yuanbin Deng Luca Balice Anke Kaletsch Martin Bram Christoph Broeckmann 《Advanced Engineering Materials》2023,25(18):2300145
Electric current-assisted sintering (ECAS) is a promising powder consolidation technique that can achieve short-term sintering with high heating rates. Currently, main methods of performing ECAS are indirect heating of the powder compact in a conductive tool or direct heating with current flowing through the powder compact. Various influencing factors have been identified to explain the rapid densification during ECAS, such as ultrahigh heating rates, extra-high temperatures, and electric field. However, the key consolidation-enhancing factor is still under debate. This study aims at understanding the role of heating rate on the enhanced densification during ECAS of 8 mol% Y2O3-stabilized ZrO2 (8YSZ) by experimental and numerical methods. Two different heating modes, ultrafast high-temperature sintering (UHS, indirect heating) and flash sintering (FS, direct heating), are studied. The novel UHS technique is successfully applied to consolidate the 8YSZ samples. Additionally, finite element methods (FEM) combined with a constitutive model is adopted to predict the densification and grain growth. Furthermore, a comparison of UHS and FS is performed to investigate the thermal effect (heating rate) and athermal effect (electric field) individually. The results indicate that the high heating rate is the key factor of the rapid densification during UHS and FS of 8YSZ. 相似文献
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Theories and applications associated with sintering of ceramics and reducing of sintering temperature are reviewed. The whole sintering process is divided into three sub-processes as powder preparation, compaction and sintering, and each sub-process is discussed in terms of its possible contribution to the reducing of sintering temperature. New approach for practical optimization of sintering process is investigated. The application of above in the Low Temperature Co-fired Ceramics (LTCC) is discussed. Meanwhile, many successful applications in reducing the sintering temperatures are presented. 相似文献
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Viorel Sandu Gheorghe Aldica Raluca Damian Zhi-Chao Guo Hong-Li Suo 《Journal of Superconductivity and Novel Magnetism》2013,26(2):361-369
We have studied the one-step procedure for simultaneous synthesis and sintering of SiC-doped MgB2 by the spark plasma sintering technique. Two types of composition, one in which Mg is strongly deficient, with the atomic ratio $\mathrm{B/Mg} = 3.75$ , and one in which Mg content is slightly higher than the stoichiometric value, specifically $\mathrm{B/Mg} = 1.87$ , were investigated. The amount of SiC was 12 wt.% and 9 wt.%, respectively. For comparison we also studied the way the deficit of Mg can be compensated in a second process of sintering. The sample with Mg deficit shows that SiC is left almost unreacted but the results are spectacular: the highest critical temperature, 36.5 K, the highest upper critical field and the highest self-field critical current density 6.7×105 A/cm2 at 10 K. In the sample with overstoichiometric Mg, SiC is decomposed, carbon diffuses within MgB2 but the critical temperature is only of 35.8 K and the zero-field critical current density is one order of magnitude lower. The compensation of the deficit of Mg in the two-step procedure is not efficient. The critical temperature is even lower, 35.8 K, the upper critical field is also lower despite SiC decomposition and C diffusion within MgB2 and the critical current density is slightly above 105 A/cm2. However, at low temperatures and fields of order 7 T the sample with overstoichiometric Mg and the sample prepared by the two-step procedure have higher critical current density. 相似文献
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