Effect of ball-milling granulation with PVB adhesive on the sinterability of co-precipitated Yb:YAG nanopowders

Ball-milling granulation parameters with polyvinyl butyral (PVB) adhesive have been optimized for the preparation of granulated Yb:YAG powders, using the co-precipitated raw powders. The influence of the amount of PVB (0-1.5 wt%) and ball-milling time (0-20 h) on the phase composition, particle size and morphologies of resultant powders is evaluated. The results show that ball milling for 10 h breaks the sintering neck of the particles while 0.5 wt% PVB adhesive contributes to ball-milling granulation and boosts the dispersion of granulated powders. It is found that when ball-milled with 0.5 wt% PVB for 10 h, the powders show high sintering activity. Using these granulated nanopowders, nearly full dense Yb:YAG ceramic with 99.6% of theoretical density was obtained by vacuum sintering at 1750 °C for 15 h. The optical transmittance of Yb:YAG ceramic reaches up to 80% in the visible light region and 82% at 1030 nm. The sample exhibit pore-free structures and the average grain size is about 9 μm. Experimental evidence proved that ball-milling granulation with PVB adhesive could be an effective and facile method to improve sinterability of nanopowders.