【摘要】 研究了以聚乙烯亚胺(PEI)为分散剂,ZrB2粉体在水相中的分散性能.结果显示ZrB2的等电点在pH为5.7,加入PEI后的等电点移到pH为11.5.以PEI为分散剂,在pH为8.0处制备了固含量达45vol%的ZrB2-20vol%SiC陶瓷浆料.采用注浆成型方法制备了相对密度为53%的ZrB2-SiC陶瓷坯体,并对其进行了无压烧结,同时研究了硼粉为烧结助剂对其致密化及性能的影响.结果表明:硼粉为烧结助剂,实现了ZrB2-SiC陶瓷的完全致密化的同时,也降低了ZrB2-SiC陶瓷的烧结温度,2100℃烧结3h后的陶瓷维氏硬度为(17.5±0.5)GPa,弯曲强度为(406±41)MPa,断裂韧性为(4.6±0.4)MPa·m1/2.更多还原

【Abstract】 The dispersion of ZrB2 particles in water was investigated using polyethyleneimine (PEI) as a dispersant. Results showed that the ZrB2 slurry had a isoelectric point of pH=5.7. The application of PEI changed the isoelectric point of the ZrB2 slurry to pH=11.5. High solids loading (45vol%) ZrB2-20vol% SiC slurries were prepared at pH=8.0 by adding 1.0wt% PEI. The green body prepared by slip casting had a relative density of 53%. The effects of boron as a sintering aid on the pressureless sintering process of the ZrB2-20vol% SiC ceramics were investigated. Nearly fully dense ZrB2-SiC composites were obtained by sintering at 2100℃ for 3 h. The sintered ceramics demonstrated a Vickers hardness of (17.5±0.5)GPa,a flexure strength of (406±41)MPa,and a fracture toughness of (4.6±0.4)MPa·m1/2.更多还原