Uniaxial compaction and sintering of ZrO2-3 mol% Y2O3 using rubber and PEG solutions as binders

In the study, investigations were conducted on the uniaxial compaction of samples made from ultrafine ZrO2-3 mol% Y2O3 powder with varying concentrations of binders. Butadiene rubber solution in petrol and aqueous solutions of polyethylene glycols (PEG-400, PEG-1500 and PEG-4000) at concentrations of 6, 12 and 18 % were employed as binders. An exponential increase in the density of all obtained compacts followed a logarithmic trend, reaching 100 % as the compaction pressure increased from 50 to 400 MPa. The density of all green bodies after binder removal, as a function of pressure and initial binder concentration, can be satisfactorily described by a single equation. According to this equation, the binder fills the pores in the green body while having a minimal impact on the volumetric concentration of the solid phase (Zirconia Oxide). The utilization of the PEG-1500 solution as a binder enabled the attainment of the maximum density, which was 4 % higher than the presented averaged trend. The phase composition of the sintered samples consisted solely of tetragonal zirconia. It was determined that increasing the sintered sample density by augmenting the compaction pressure and reducing the binder concentration led to an increase in the green body density from 96.9 to 99.6 %, hardness from 1100 to 1350 HV, fracture toughness from 4.5 to 5.9 MPa*m1/2 and strength from 123 to 960 MPa. The use of powders with a binder mass fraction of 6-12 % enabled the fabrication of cups with a diameter of 5 mm, which could not be compacted at lower binder concentrations or without a binder due to cracking.