爆炸压实ZrB_2-SiC超高温陶瓷的密度与组织

Densities and microstructure of ultrahigh temperature ceramics ZrB_2-SiC prepared by explosive compaction

为了研究炸药对ZrB2-SiC超高温陶瓷密度与组织的影响,采用爆炸压实工艺制备了SiC纳米颗粒和SiC晶须分别增韧的两类ZrB2基超高温陶瓷复合材料.研究发现:选择低速的硝酸铵或高速的黑索今时,两类ZrB2-SiC爆炸压实坯密度都比较低,而选择混合炸药时致密效果较好;采用225 g黑索今与75 g硝酸铵的混合炸药时,ZrB2-SiCw超高温陶瓷的最高致密度达到了95.25%,ZrB2-SiCnm超高温陶瓷的最高致密度达到了96.12%;球磨混料后,纳米颗粒或晶须都能均匀弥散在微米ZrB2基体中.与ZrB2-SiCw超高温陶瓷爆炸压实坯相比,ZrB2-SiCnm超高温陶瓷显微组织细小,且不出现ZrB2与SiC相的富集,是比较理想的显微结构.

To study the effect of explosive on densities and microstructure of ultrahigh temperature ceramics ZrB2-SiC,two kinds of ZrB2 matrix toughened by SiC whisker or SiC nanoparticles were prepared by explosive compaction.When low speed explosive Ammonium or high speed RDX was chosen,the densities of ZrB2-SiC ceramics were lower.While,when the hybrid explosive of Ammonium and RDX was chosen,their densities were higher.If the hybrid explosive of 225 g RDX and 75 g Ammonium was used,the maximum value of the densities of ZrB2-SiCw ultrahigh temperature ceramics was 95.25%,and that of ZrB2-SiCnm was 96.12%.The SiC nanoparticles or SiC whisker can be uniformly dispersed in the micrometer ZrB2 matrix after mixing.Compared with ZrB2-SiCw,the microstructure of ZrB2-SiCnm is finer,more uniform and perfect without phase segregation.