水基流延B4C陶瓷材料制备工艺研究

摘要

B4C ceramic film was prepared by aqueous tape-casting with boron carbide powder as starting material,Al2O3 and Y2O3as sintering aids,Polymine (PEI) as dispersant,polyethyleneglycol (PEG) as plasticizer,poval (PVA) and gelatin as binder respectively. The influences of pH,dispersant content,the kinds and content of binder on rheological property and the effect of the sintering temperature on the microstructure and mechanical properties of B4C ceramic composites were studied. The experimental results indicated that,in acid medium,the slurry with good stability and rheology could be prepared with 1.0 wt.% PEI,5.0 wt.% PVA or 7.0 wt.% gelatin. Cast film had better flexibility and strength with PVA as binder,and gel property with gelatin as binder. The results indicated that the best mechanical properties of B4C ceramic composites were achieved when the sintering temperature was 2000℃,the relative density,bending strength,fracture toughness and vickers hardness of the composites were 98.4%,513.19 MPa,6.58 MPa· m1/2,38.6 GPa,respectively.%以B4C粉为主要原料、Al2O3粉与Y2O3粉为烧结助剂、聚乙酰亚胺(PEI)为分散剂、聚乙二醇(PEG)为增塑剂、分别以聚乙烯醇(PVA)和明胶为粘结剂,采用水基流延法制备B4C陶瓷材料.研究了pH值、分散剂用量、粘结剂种类和用量对流延浆料流变性的影响以及烧结温度对B4C陶瓷材料显微结构与力学性能的影响.实验结果表明,在酸性条件下,1.0wt.%的PEI,5.0wt.%的PVA或7.0 wt.%明胶制得的浆料分散稳定,流变性好;PVA为粘结剂制备的流延膜柔韧性和强度较好,明胶为粘结剂制备的流延膜具有凝胶性.烧结温度为2000℃时,B4C陶瓷材料力学性能最佳,相对密度、抗弯强度、断裂韧性和维氏硬度分别达到98.4%、484.63 MPa、5.86 MPa·m1/2、38.2 GPa.