Room temperature enhancement of flexural strength in silicon carbide green body via the addition of cellulose nanofiber
Room temperature enhancement of flexural strength in silicon carbide green body via the addition of cellulose nanofiber
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DOI：
10.1007/s00170-023-10805-7
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发表时间：
2023-01
期刊：
影响因子：
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通讯作者：
Teruyoshi Kanno;H. Kurita;F. Narita
中科院分区：
文献类型：
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作者：
Teruyoshi Kanno;H. Kurita;F. Narita
通过在碳化硅（SiC）浆料中加入纤维素纤维（CNF）并在室温下干燥，对采用自动注浆成型技术制备的SiC绿色坯体进行了强化。通过液相重量比（水与CNF浆料）为80：20的CNF改性的SiC绿色坯体的测量的弯曲强度为813 ± 37 kPa，比未改性的绿色坯体的强度大1.5倍。由于原料颗粒和CNF之间的氢键位点的数量增加，强度得到改善。在250 °C下退火后，弯曲强度的降低表明通过捕获在CNF上的水发生结合位点。CNF的加入增加了SiC浆料的粘度和屈服应力，无论使用何种CNF，SiC浆料都保持宾汉假塑性行为。此外，该添加剂对烧结SiC体的相对密度、微观结构和晶相没有影响。因此，向SiC浆料中添加CNF有助于在加工期间处理绿色体，并且对自动铸造没有显示出有害影响。
Silicon carbide (SiC) green bodies fabricated using robocasting were strengthened by incorporating cellulose nanofiber (CNF) into a SiC slurry and just drying at room temperature. The measured flexural strength of a SiC green body modified via the CNF with a liquid phase weight ratio (water-to-CNF slurry) of 80:20 was 813 ± 37 kPa, 1.5 times larger than the strength of an unmodified green body. The strength was improved due to the increased number of hydrogen-bonding sites between the raw particles and CNF. After annealing at 250 °C, the lowering of the flexural strength indicated the occurrence of the bonding sites via water that was trapped on the CNF. The addition of CNF increased the viscosity and yield stress of the SiC slurry, which remained in the Bingham pseudoplastic behavior regardless of the CNF used. Moreover, this addition showed no effect on the relative densities, microstructures, and crystalline phases of the sintered SiC body. Therefore, the addition of CNF to the SiC slurry aided in handling the green body during processing and showed no detrimental effects on robocasting.