The study of wear properties of ZTA ceramic particlesreinforced High chromium cast iron matrix composites

The study of wear properties of ZTA ceramic particlesreinforced High chromium cast iron matrix composites 
 
目前，高铬铸铁作为典型的耐磨材料应用于矿山、水泥等多个领域。然而高铬铸铁耐磨性偏低、且耐磨性与强韧性相互制约，已成为制约行业发展的关键技术难题。陶瓷颗粒增强高铬铸铁基复合材料具备金属材料的高强度、良好塑形和冲击韧性、易成型等特点，又具备陶瓷增强体的高硬度、高耐磨性等优点，有广阔的应用前景。本论文以高铬铸铁和 ZTA(ZrO2增韧 Al2O3)陶瓷颗粒为原料，采用熔体铸渗法结合多孔陶瓷预制体制备工艺成功制备了 ZTA 陶瓷颗粒增强高铬铸铁基复合材料。采用高温磨料磨损试验机、冲刷腐蚀磨损试验机结合 SEM、EDS、XRD 等检测手段研究了不同颗粒度 ZTA 陶瓷颗粒增强高铬铸铁基复合材料在不同温度、不同气压下的高温磨料磨损性能，以及在泥浆中的冲蚀磨损性能。研究结果如下：

（1）加入 ZTA 陶瓷颗粒后，陶瓷-金属基复合材料的高温磨料磨损性能明显好于单一高铬铸铁基体；在相同的温度条件下，ZTA 陶瓷颗粒粒径在 1.7~2.36mm 之间时复合材料的高温耐磨性最好；在相同的气压下，ZTA 陶瓷颗粒增强高铬铸铁基复合材料所处的环境温度越高，磨料磨损损失越严重；在正常大气压下，复合材料的高温磨料磨损质量损失比低真空时要小；ZTA 陶瓷颗粒增强高铬铸铁基复合材料的高温磨料磨损机制主要有磨粒磨损、疲劳磨损、氧化磨损和粘着磨损等。

（2）加入陶瓷颗粒可以减小高铬铸铁的冲蚀磨损质量损失，其中 1.7~2.36mm 粒径ZTA 陶瓷增强高铬铸铁基复合材料的冲蚀磨损质量损失率最小；ZTA 陶瓷颗粒增强高铬铸铁基复合材料冲蚀磨损后的形貌多为均匀的腐蚀坑，其磨损机制为切削磨损和犁沟磨损；0.6~0.85mm 粒径 ZTA 陶瓷增强高铬铸铁基复合材料的腐蚀分量占质量损失的比例最大；反推磨损分量占质量损失的比例则高铬铸铁最大，1.7~2.36mm 粒径陶瓷增强复合材料次之，0.85~1.7mm 再次，0.6~0.85mm 最小。

关键词： ZTA 陶瓷；复合材料；高温磨料磨损；冲蚀磨损
 

At this time, high chromium cast iron as a typical kind of wear-resistant material is used in  many  areas  such  as  mining  and  cement  industry.  However,  its  resistance  is  low  because resistance  is  restrained  with  toughness.  And  the  low  resistance  has  become  a  key  technical problem  which  can  constrain  the  development  of  this  industry.  Ceramic  particles  reinforced high chromium cast iron matrix composites both have the good properties of metal material and ceramics. They have high strength, good shaping property, good impact toughness, high hardness  and  high  wear  resistance.  So  the  composites  have  broad  application  prospects. Ceramic  particles  reinforced  high  chromium  cast  iron  matrix  composites  had  been  prepared successfully  with  liquid  metal  infiltration  technology  and  fabrication  of  porous  ceramic preforms，using ZTA(ZrO2 toughened Al2O3) ceramic particles and high chromium cast iron as  raw  materials.  The  high  temperature  abrasive  wear  resistance  of  different  size  of  ZTA ceramic  particle  reinforced  high  chromium  cast  iron  matrix  composites  at  different temperatures  and  under  different  pressure  was  studied  (by  OM\SEM\XRD  methods).  In addition, the erosive wear resistance of different size of ZTA ceramic particle reinforced high chromium cast iron matrix composites was studied in the mud. The results are as follows:

(1)  After  adding  ZTA  ceramic  particles,the  high  temperature  abrasive  wear performances were significantly better than single high chromium cast iron base. Under the same  temperature，the  high  temperature  wear  resistance  of  composites  with  ZTA  ceramic particles which sizes are between 1.7~2.36mm is best. Under the same pressure, the mass loss of  the  composites  in  higher  temperature  is  more.  Under  normal  atmospheric  pressure，the mass loss of composites’ high temperature abrasive wear is less than that in low vacuum. The high  temperature  abrasive  wear  mechanism  of  ZTA  ceramic  particle  reinforced  high
chromium is mainly abrasive wear，fatigue wear，oxidation wear and adhesive wear.

(2) Adding ceramic particle can reduce mass loss of high chromium cast iron. The mass loss of composites with 1.7~2.36mm size ZTA ceramic particle is lest. The morphologies of ZTA reinforced composites after erosion are corrosion pits. Its mechanisms are cutting wear and  plowing  abrasion.  The  percent  of  corrosive  component  accounting  for  mass  loss  of  composites  with  0.6~0.85mm  ZTA  particles  is  most.  Thrust  reverser，the  percent  of  wear component  accounting  for  mass  loss  of  high  chromium  cast  iron  is  most.  The  percent  of composites  with  1.7~2.36mm  ZTA  particles  is  second.  The  percent  of  composites  with
0.6~0.85mm ZTA particles is lest.

Key words: ZTA ceramic; Composites; High temperature abrasive wear; Erosive wear