The combustion synthesis has been focused on the considerable attention as a rapid high temperature process to synthesize refractory materials and intermetallics with high formation energies. Silicides have recently been investigated as potential materials for high temperature structural application...
The combustion synthesis has been focused on the considerable attention as a rapid high temperature process to synthesize refractory materials and intermetallics with high formation energies. Silicides have recently been investigated as potential materials for high temperature structural applications and for application in the electronics industry. Among these silicides, NbSi2 and ZrSi2 have many interesting properties such as high melting point, low density and extremely high resistance to oxidation. However as in the case of many intermetallic compounds, the current concern about these materials focuses on their low fracture toughness below the ductile-brittle transition temperature. To improve their mechanical properties, it is effective to use as form of composite with other phase and nanostructured materials. Nanostructured materials have widely investigated because they displayed a side functional diversity and exhibited enhanced or different properties compared with bulk materials. Particularly, in the case of nanostructured ceramics, the presence of a large fraction of grain boundaries can lead to unusual or better mechanical, electrical, optical, sensing, magnetic, and biomedical properties. In recent days, nanocrystalline powders have been developed by the thermochemical and thermomechanical process named as spray conversion process, co-precipitation and high energy ball milling. However, the grain size in sintered materials become much larger than that in pre-sinterd powders due to a fast grain growth during conventional sintering process. Therefore, even though the initial particle size is less than 100nm, the grain size increases rapidly up to 500nm or larger during the conventional sintering. So, controlling grain growth during sintering is one of the keys to the commercial success of nanostructured materials. In this regard, the high frequency induction heated sintering method which can make dense materials within 2 minutes, has been shown to be effective in achieving this goal. In this work, the dense NbSi2-SiC, ZrSi2-SiC, 4NbSi2-Si3N4 and 4ZrSi2-Si3N4 composites were synthesized by HFIHCS method within 2 minutes in one step from the mixture of raw materials. The hardness and fracture toughness of NbSi2-SiC, ZrSi2-SiC, 4NbSi2-Si3N4 and 4ZrSi2-Si3N4 were 1300kg/mm2 and 3.1MPa·m1/2, 1180kg/mm2 and 2.5MPa·m1/2, 680kg/mm2 and 3.1MPa·m1/2 and 755kg/mm2 and 4.6MPa·m1/2 , respectively.
The combustion synthesis has been focused on the considerable attention as a rapid high temperature process to synthesize refractory materials and intermetallics with high formation energies. Silicides have recently been investigated as potential materials for high temperature structural applications and for application in the electronics industry. Among these silicides, NbSi2 and ZrSi2 have many interesting properties such as high melting point, low density and extremely high resistance to oxidation. However as in the case of many intermetallic compounds, the current concern about these materials focuses on their low fracture toughness below the ductile-brittle transition temperature. To improve their mechanical properties, it is effective to use as form of composite with other phase and nanostructured materials. Nanostructured materials have widely investigated because they displayed a side functional diversity and exhibited enhanced or different properties compared with bulk materials. Particularly, in the case of nanostructured ceramics, the presence of a large fraction of grain boundaries can lead to unusual or better mechanical, electrical, optical, sensing, magnetic, and biomedical properties. In recent days, nanocrystalline powders have been developed by the thermochemical and thermomechanical process named as spray conversion process, co-precipitation and high energy ball milling. However, the grain size in sintered materials become much larger than that in pre-sinterd powders due to a fast grain growth during conventional sintering process. Therefore, even though the initial particle size is less than 100nm, the grain size increases rapidly up to 500nm or larger during the conventional sintering. So, controlling grain growth during sintering is one of the keys to the commercial success of nanostructured materials. In this regard, the high frequency induction heated sintering method which can make dense materials within 2 minutes, has been shown to be effective in achieving this goal. In this work, the dense NbSi2-SiC, ZrSi2-SiC, 4NbSi2-Si3N4 and 4ZrSi2-Si3N4 composites were synthesized by HFIHCS method within 2 minutes in one step from the mixture of raw materials. The hardness and fracture toughness of NbSi2-SiC, ZrSi2-SiC, 4NbSi2-Si3N4 and 4ZrSi2-Si3N4 were 1300kg/mm2 and 3.1MPa·m1/2, 1180kg/mm2 and 2.5MPa·m1/2, 680kg/mm2 and 3.1MPa·m1/2 and 755kg/mm2 and 4.6MPa·m1/2 , respectively.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.