直接凝固注模成型是一种新颖的原位凝固成型工艺，特别适合于复杂形状陶瓷部件的成型．通过粉体的表面改性、浆料ｐＨ值的调节以及引入高效分散剂等途径制备出了低粘度高固含量的氮化硅浆料，通过直接凝固注模成型可以获得适当的素坯密度和强度．坯体气孔分布均匀，为较窄的单峰分布，断口光滑平整，坯体各部位密度具有很好的均匀性．在相对较低的烧结温度下（１７５０℃），成型坯体经过无压烧结可达到理论密度的９８％，基本实现致密化．烧结体结构均匀，晶粒均匀生长，发育良好．经１８００℃烧结２ｈ后，抗折强度达７５８．４ ＭＰａ，断裂韧性为６．３ＭＰａ·ｍ１／２．
Direct coagulation casting (DCC) is a novel in-situ shape-forming method for ceramic green bodies, especially for fabricating parts with complex shapes. On
the basis of a series of studies, such as surface modification of silicon nitride powder, adjustment of pH in dispersing medium and introduction of efficient dispersant,
silicon nitride suspension with low viscosity and high solid loading was prepared. After optimizing the forming parameters, silicon nitride green body with 60% of
the theoretical density and sufficient strength for demoulding was produced. The green body has homogeneous microstructure and smooth fractured surface. The pore
size distribution of the green body is uniform, narrow and unimodal. At a lower sintered temperature (1750℃), bulk density of the material by pressless
sintered is 98% of the theoretical value. The specimen sintered at 1800℃ for 2h has a homogeneity microstructure, flexure strength of 758.4MPa and a fracture toughness of 6.3 MPa·m1/2.
参考文献
| [1] | |
| [2] | Lange F F. J Am. Ceram. Soc., 1989, 72(1): 3--15 . [2] Gauckler L J, Graule T J. Swiss Pat. 02377(1992) |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%