论文部分内容阅读
选用纳米Zr O2粉末作为Mo Si2基复合材料室温增韧和高温弥散强化的第二添加相,利用喷雾造粒方法制备了用于等离子喷涂的Zr O2-Mo Si2复合粉末。采用标准漏斗法测量了复合粉末的松装密度,通过RISE-2008激光粒度分析仪测试了复合粉末的粒度及其分布,借用扫描电镜(SEM)观察了复合粉末的表面形貌与结构,结合试验测定结果及理论计算结果分别研究了起始粉末的球磨时间、料浆中固含量、粘结剂含量及分散剂含量、喷雾干燥条件对粉末造粒的影响规律。结果表明:当球磨时间为12 h时,粉末的粒度分布于1~2μm之间;当料浆成分中固含量为70%,粘结剂含量为10%,分散剂含量为1%时,料浆具有良好的流动性及稳定性;喷雾干燥过程中,进风温度为200℃,出风温度为120℃,蠕动泵速率为2 ml·min-1,进气气压为0.2 MPa时,所制备的团聚型复合粉末成球度较高,表面致密且分散,颗粒之间无粘结现象,颗粒粒径的平均值为42μm,松装密度为2.17 g·cm-3,经1200℃真空烧结热处理后的团聚型复合粉末具有较高的流动性。
ZrO2-MoSi2 composite powder for plasma spraying was prepared by spray granulation method using nano-ZrO2 powder as the second additive phase of MoSi2-based composite at room temperature and high temperature dispersion strengthening. The loose density of the composite powder was measured by standard funnel method. The particle size and distribution of the composite powder were measured by RISE-2008 laser particle size analyzer. The surface morphology and structure of the composite powder were observed by scanning electron microscopy (SEM) The results of the measurement and the theoretical calculation results show that the milling time of the starting powder, the solid content in the slurry, the content of the binder and the content of the dispersant, and the influence of the spray drying conditions on the powder granulation are studied respectively. The results showed that when the ball milling time was 12 h, the particle size distribution of the powder was between 1 and 2 μm. When the content of the slurry was 70%, the binder content was 10% and the dispersant content was 1% The slurry had good fluidity and stability. During the spray drying process, the inlet air temperature was 200 ℃, the outlet air temperature was 120 ℃, the peristaltic pump rate was 2 ml · min-1 and the inlet pressure was 0.2 MPa The average particle size of the particles was 42μm and the bulk density was 2.17 g · cm-3. After heat treatment at 1200 ℃ in vacuum, After the reunion type composite powder has high fluidity.