本文介绍用非均相沉淀法制备的纳米SiC－Al2O3复合粉体经放电等离子超快速烧结得到晶内型的纳米复相陶瓷，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．与热压烧结相比，可降低烧结温度200℃以上．力学性能研究结果表明，在1450℃超快速烧结得到的纳米复相陶瓷的抗弯强度高达1000MPa，维氏硬度为19GPa，断裂韧性也比Al2O3有所提高．TEM像显示纳米SiC颗粒大多分布在Al2O3母体晶粒内，而断裂表面的SEM像表明，穿晶断裂是其主要的断裂模式，这是所制备的纳米复相陶瓷力学性能大幅提高的主要原因．
Heterogeneous precipitation methods were used to produce 5 vol% SiC-Al2O3 nanocomposite powder, from aqueous suspension of Nano-SiC (70 nm), aqueous Solution of aluminium chloride and ammonia. The SiC-Al2O3 nanocomposites
were superfast densified by spark plasma sintering (SPS) process with heating to a sintering temperature range from 1350 to 1550℃, at a
heating rate of 600℃/min, without holding time, and then fast cooling to 600℃ within 2～3 minutes; and high density nanocomposites
were obtained. The expermental results show that bending stregth of 5 vol% SiC-Al2O3 nanocomposites sintered at 1450℃ is as high as 1000 MPa,
while vickers hardness about 19 GPa. Fracture toughness of the sample sintered at 1500 ℃ is about 4 MPa·m1/2, a little bit higher than
that of Al2O3 ceramics. Microstructure studies show that nano-SiC particles are mainly located in Al2O3 grains and the fracture mode of the nanocomposites
is mainly transgranular fracture. Due to the expansion coefficient mismatch and most of SiC particles located in Al2O3 gains, the tensile stress, which
weakens matrix grains and originates the transgranular fracture, will appear when the samples cool down from the sintering temperature.
参考文献
| [1] | Niihara K. J. Ceram. Soc. Jpn., 1991, 99: 974--982 2 王宏志，高濂，归林华，郭景坤. (WANG Hong-Zhi { et al). 无机材料学报(Journal of Inorganic Materials)， 1997, 12: 671--674 3 高濂，洪金生，宫本大树，Sebastian D. De la T. (GAO Lian et al).无机材料学报(Journal of Inorganic Materials)， 1998, 13 (1): 18--22 4 高濂，洪金生，宫本大树，Sebastian D. De la T. (GAO Lian et al). 无机材料学报(Journal of Inorganic Materials)， 1998, 13 (6): 904--908 5 Zhao J, Stearns L, Harmer M. P, et al. J. Am Ceram. Soc., 1993, 76: 503--510 6 Piciacchio A, Lee S, Messing G. L. J. Am. Ceram. Soc., 1994, 77: 2157--2164 |
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