High‐Hardness Diamond Composite Consolidated by Spark Plasma Sintering

A high‐hardness diamond‐based composite was synthesized by spark plasma sintering (SPS) under 100 MPa, using SiC‐coated diamond powder prepared via chemical vapor deposition (CVD). SiC layers 20–40 nm were uniformly deposited on diamond powders by a rotary CVD technique. The SiC‐coated diamond powder was consolidated with SiO powder by SPS at the sintering temperature of 1873 K, resulting in the formation of fully compacted mosaic microstructure with the Vickers hardness of 36 GPa.     

Spark Plasma Sintering of Magnesia-Doped Alumina with High Hardness and Fracture Toughness

The effect of grain size of magnesia and its content as well as spark plasma sintering conditions on the density, grain size, strength, hardness, and toughness of alumina was investigated. Spark plasma sintering conditions were optimized at 1150°C/5 min/175°C/min. Addition of 100 nm magnesia gave higher density levels (99.5%), while better strength (600 MPa), hardness (25 GPa), and fracture toughness (4.5 MPa·m^1/2) were obtained with 15 nm magnesia. The good strength and hardness is attributed to the submicrometer grain size of the matrix, and the improved toughness to the presence of Mg-rich nanoparticles and nanopores at grain boundaries.     

Spark Plasma Sintering of Functionally Graded SiO2/Mo Laminated Layer Material

A functionally graded sintered body consisting of laminated SiO₂/Mo layers was fabricated using spark plasma sintering. A high sintered‐body density was achieved using fine powders of SiO₂ (4.0 μm) and Mo (1.3 μm), which ensured no cracks were formed between layers. The highest joining stress (1.2 MPa) was found to occur at the interface between SiO₂ layers with 0 and 8 vol% Mo, with the electrical resistance decreasing rapidly when the Mo content was increased to 13 and 22 vol%. This is attributed to the use of spark plasma sintering, suggesting further work is needed to fully optimize this process.     

Rapid Reactive Synthesis and Sintering of Submicron TiC/SiC Composites through Spark Plasma Sintering

Submicrometer TiC/SiC composites were fabricated by a rapid reactive sintering process through spark plasma sintering (SPS) technique using the carbon, titanium, and nanosized-SiC powders without any additive. It was found that the composite could be sintered in a relatively short time (8 min at 1480°C) to 97.9% of theoretical density. After sintering, the phase constituents and microstructures of the samples were analyzed by X-ray diffraction techniques and observed by scanning electron microscopy. The effect of nanosized and microsized SiC additives on the microstructure of TiC/SiC composites was investigated.     

放电等离子烧结工艺制备Ti2AlC材料的研究

以元素粉钛、铝、碳为原料，采用放电等离子烧结工艺在1100℃的温度下成功地制备了高纯、致密Ti2AlC材料。合成材料的x-射线衍射(XRD)和扫描电镜(SEM)分析的结果表明：多晶体Ti2AlC形貌为板状结晶，晶粒大小平约为20μm，厚度在3—5μm。     

放电等离子烧结制备Ti/Al2O3复合材料

Ti基金属复合材料是一种新型高温结构材料.本文利用放电等离子烧结技术,在温度1250℃、压力30MPa、真空度6Pa,保温时间10min条件下,制备了相对致密度较高的Ti/Al2O3复合材料.借助XRD,SEM,EDS等测试手段对该复合材料的物相组成、界面反应、微观结构以及致密度进行了观察与分析.结果表明:利用SPS技术制备Ti/Al2O3的复合材料,晶粒细小且分布均匀,结构致密、2相之间结合状态良好,相对致密度随材料中陶瓷相含量的增多而有所降低.Ti,Al2O32相之间无明显界面化学反应发生.     

放电等离子烧结工艺制备Ti_2AlC材料的研究

以元素粉钛、铝、碳为原料 ,采用放电等离子烧结工艺在 1 1 0 0℃的温度下成功地制备了高纯、致密Ti2 AlC材料。合成材料的X -射线衍射 (XRD)和扫描电镜 (SEM)分析的结果表明 :多晶体Ti2 AlC形貌为板状结晶 ,晶粒大小平均约为 2 0 μm ,厚度在 3～ 5 μm。     

放电等离子烧结工艺制备Ti2A1C材料的研究

以元素粉钛、铝、碳为原料,采用放电等离子烧结工艺在1100℃的温度下成功地制备了高纯、致密Ti2AlC材料.合成材料的X-射线衍射(XRD)和扫描电镜(SEM)分析的结果表明:多晶体Ti2AlC形貌为板状结晶,晶粒大小平均约为20μm,厚度在3～5μm.     

Alumina/Silicon Carbide Laminated Composites by Spark Plasma Sintering

Ceramic laminates composed of alumina/silicon carbide composite layers were produced by spark plasma sintering (SPS). Monolithic composite disks containing up to 30 vol% of silicon carbide were fabricated by stacking together and cosintering by SPS green layers prepared by tape casting water-based suspensions. An engineered laminate with a specific layer combination that is able to promote the stable growth of surface defects before final failure was also designed and produced. Fully dense materials with an optimum adhesion between the constituting layers and a homogeneous distribution of the two phases were obtained after SPS. Monolithic composites showed an increasing strength with SiC load, and biaxial strength values as high as 700 MPa were observed for a SiC content of 30 vol%. The engineered laminate showed a peculiar crack propagation that is responsible for the high strength value of about 600 MPa and for the evident insensitivity to surface defects.     

壳核式Al2O3-Y2O3 /ZrB2复合粉体的放电等离子烧结行为研究

ZrB2具有优良的物理特性和化学稳定性而应用于许多领域,但是ZrB2难以烧结致密和在高温条件下容易被氧化.为了充分发挥ZrB2的优点,改善ZrB2的缺点,本文采用共沉淀法制备壳核式Al2O3-Y2O3 /ZrB2复合粉体,通过放电等离子烧结法制备高致密的ZrB2-YAG陶瓷.在相同实验条件下得到的纯ZrB2陶瓷的相对密度都很低,在85%以下.通过此种方法加入少量YAG后,烧结密度得到明显提高,随YAG添加量的增加相对密度增加.添加量超过30wt%后,可以达到几乎完全致密的ZrB2-YAG陶瓷.     

TiB2对放电等离子烧结法合成Ti3AlC2/TiB2复合材料性能和结构的影响

放电等离子烧结合成了Ti_3AlC_2/TiB_2复合材料,对其进行了密度、硬度、相含量、断裂韧性和弯曲强度以及微观结构的测试,比较系统地研究了TiB_2对Ti_3AlC_2/TiB_2复合材料性能和结构的影响。实验结果表明:在Ti_3AlC_2中添加适量的TiB_2,可以在断裂韧性略有降低的情况下,得到高硬度和高弯曲强度的致密的Ti_3AlC_2/TiB_2复合材料。     

Al对等离子放电烧结法合成Ti3SiC2的影响研究

以元素为原料，Al为助剂，采用等离子放电烧结(SPS)工艺合成Ti3SiC2块体材料，通过X射线衍射分析和对SPS过程参数的研究表明：适量A1能促进Ti3SiC2的反应合成，提高合成材料的纯度，但Al也会使Ti3SiC2的热稳定性降低。     

由放电等离子烧结的WC-ZrO2 纳米复合材料的发展

采用放电等离子烧结(SPS)技术烧结WC-ZrO2纳米复合材料，在相对较低的烧结温度1300℃下，较短的保温时间5min，制备了致密化、高硬度、韧性适中的WC-ZrO2纳米复合材料。     

放电等离子烧结制备AlON陶瓷

以A1N粉和A12O3为原料，用放电等离子烧结(SPS)技术制备单相A1ON陶瓷。研究表明：用SPS技术在1700℃仅保温3min就可得到99TD％的A1ON陶瓷，该技术是实现A1ON陶瓷低温快速烧结的有效途径。     

Electroconductive Alumina-TiC-Ni nanocomposites obtained by Spark Plasma Sintering

In the present work, the processing and characterization of electroconductive Alumina-TiC-Ni nanocomposites obtained by Spark Plasma Sintering (SPS) are described. These nanocomposites are singular due to the excellent mechanical properties they present (particular regarding Vickers hardness, 25.6 ± 0.7 GPa), as well as their extremely good wear behaviour, studied under “ball-on-disk” dry sliding conditions. The wear rate obtained was 25 times (almost 1.5 orders of magnitude) smaller than the value obtained for a monolithic alumina sintered under the same conditions. Flexural strength had been improved up to 75% with respect to the monolithic alumina processed under the same conditions. As these nanocomposites can be machined by electroerosion (EDM), they can adopt any shape for devices requiring a good mechanical performance and low wear rates.     

Preparation of Dense MgB2 Bulk Superconductors by Spark Plasma Sintering

Fully dense MgB₂ bulk specimens (∼higher than 99% dense) were prepared using spark plasma sintering (SPS) at 1250°C for 15 min. Microstructure analyses revealed that faceted MgO particles of ∼8% volume fraction were dispersed in the MgB₂ matrix. A sharp superconducting transition with an onset temperature of 38.5 K was confirmed by both magnetization and resistivity measurements.     

Development of WC–ZrO2 Nanocomposites by Spark Plasma Sintering

In the present work, we report the processing of ultrahard tungsten carbide (WC) nanocomposites with 6 wt% zirconia additions. The densification is conducted by the spark plasma sintering (SPS) technique in a vacuum. Fully dense materials are obtained after SPS at 1300°C for 5 min. The sinterability and mechanical properties of the WC–6 wt% ZrO₂ materials are compared with the conventional WC–6 wt% Co materials. Because of the high heating rate, lower sintering temperature, and short holding time involved in SPS, extremely fine zirconia particles (∼100 nm) and submicrometer WC grains are retained in the WC–ZrO₂ nanostructured composites. Independent of the processing route (SPS or pressureless sintering in a vacuum), superior hardness (21–24 GPa) is obtained with the newly developed WC–ZrO₂ materials compared with that of the WC–Co materials (15–17 GPa). This extremely high hardness of the novel WC–ZrO₂ composites is expected to lead to significantly higher abrasive-wear resistance.     

Enhancement of Interparticle Exchange Coupling in CoFe2O4/CoFe2 Composite Nanoceramics Via Spark Plasma Sintering Technology

Powders and nanoceramics composed of composites of CoFe₂O₄, CoFe₂, and a small amount of FeO were prepared by heating CoFe₂O₄ powder in reducing atmosphere and by sintering the product of reducing reaction at 350°C via spark plasma sintering technology. In the powders, increase in the molar ratios of CoFe₂:CoFe₂O₄ and a great change in magnetic parameters were observed with the change in heating temperature from 300°C to 400°C, and the dominance of dipole interaction over exchange coupling in the interparticle interactions was confirmed by the steps in magnetic hysteresis loops and the negative Henkel plots. However, in the nanoceramics, significant enhancement in exchange coupling was found when the sintering temperature was raised to 500°C and 650°C, which was confirmed by both the positivity of Henkel plot and the single‐phase style of the magnetic hysteresis loop.