反应烧结碳化硼低压注射成型用浆料粘度的研究

针对反应烧结B 4C陶瓷材料低压注射成型用浆料的制备问题,研究了颗粒级配、分散剂含量(质量分数)和B 4C固含量对浆料粘度的影响.研究结果表明:当B4C粉体颗粒级质量比为m(F320)∶m(F800)=6∶4,分散剂质量分数为1%,B4C固含量(质量分数)为80%时,浆料的粘度适合于低压注射成型,低压注射成型坯体中B 4C颗粒分散均匀,坯体的体积密度为1.79 g/cm^3,气孔率为2.07%,脱蜡坯体显微结构较为均匀.脱蜡坯体经过1550℃渗Si烧结后,材料的抗弯强度、断裂韧性、维氏硬度分别可达322.7 MPa、3.33 MPa·m^1/2、25.7 GPa.本实验通过控制颗粒级配,分散剂含量及B4C固含量实现了低粘度、高固含量B4C(w(B4C)=80%)浆料的制备,并有效地提高了脱蜡坯体和反应烧结B4C复合材料的性能.

Study on viscosity of slurry for low pressure injection molding of reaction-sintered boron carbide

Low-pressure injection molding technology is used to prepare RBBC(reaction bonded boron carbide).The effects of particle size distribution,dispersant content and B4C solid content on slurry viscosity were studied.For the case of powder mass ratio m(F320)∶m(F800)=6∶4,1%oleic acid and 80% solid,the slurry viscosity is most suitable for low-pressure injection molding.The volume density and porosity of green body can reach 1.79 g/cm^3 and 2.07%,respectively.The microstructure of wick-debinded green body is very uniform.After sintering at 1550℃,the Vickers hardness,flexure strength and fracture toughness are 25.68 GPa,322.69 MPa and 3.3 MPa·m^1/2,respectively.In this work,the slurry with low-viscosity and high B4C solid content(w(B4C)=80%)is prepared by controlling granular grade,the oleic acid content and B4C solid content.The performance of the wick-debinded green body and the RBBC is effectively improved.