ZrO_2(Y_2O_3)增韧SiC中介结合的金刚石聚晶烧结体的相结构与性能

Phase Structure and Properties of SiC Bonded Polycrystalline Diamond Toughed with ZrO 2 (Y 2O 3)

本文采用恒沸腾水解法制备了颗粒度均一的亚微米晶ＺｒＯ２（Ｙ２Ｏ３）粉体，并以其为增韧相，在高温（１３５０℃）超高压（５ＧＰａ）条件下制备ＺｒＯ２（Ｙ２Ｏ３）＋ＳｉＣ＋金刚石的聚晶烧结体（ＰＣＤ）。用ＸＲＤ、ＳＥＭ背散射分析、冲击韧性测定和磨耗比测定研究了不同含量Ｙ２Ｏ３稳定的ＺｒＯ２粉体对ＳｉＣ－金刚石聚晶烧结体结构及机械性能的影响，结果表明：ＺｒＯ２（Ｙ２Ｏ３）粉体中Ｙ２Ｏ３含量＜２．２ｍｏｌ％时，ＺｒＯ２以四方ｔ相＋单斜ｍ相的混合相形式存在于烧结体的结合剂基体上，ｔ相量随Ｙ２Ｏ３含量增加而增加，对ＳｉＣ－金刚石聚晶烧结体的增韧来源于相变增韧和微裂纹增韧的叠加，当Ｙ２Ｏ３含量＞２．２ｍｏｌ％时，ＺｒＯ２以１００％ｔ相存在，增韧机制为相变增韧。在２．０ｍｏｌ％～２．２ｍｏｌ％Ｙ２Ｏ３含量范围内，ＰＣＤ可获得较高的磨耗比和冲击韧性。

Abstract Submicrocrystalline ZrO 2 (Y 2O 3) powder with homogeneous particle sizes is prepared by boilinghydrolysis method. SiC bonded polycrystalline diamond (PCD) toughed with ZrO 2 (Y 2O 3) is sintered at high temperature (1350℃) and ultra high pressure (5Gpa). The effects of Y 2O 3 content on the phase structure and the mechanical properties of PCD are investigated by XRD, SEM, impact toughness and G ratio measurements. The results show that the phase composition of ZrO 2 is tetragonal phase and monoclinic phase with Y 2O 3 content less than 2.2mol% . The toughness increasing comes from phase transformation and toughening by microcracks. The amount of t ZrO 2 increases as the Y 2O 3 content increasese 100% t ZrO 2 is retained with Y 2O 3 content more than 2.2mol%. The toughness is only caused by t m phase transformation.PCD has high grinding ratio and high