that are sintered in a pressureless crucible that limits loss of li 2 o application_number US 201615010875 A description the invention is directed to a method to produce near full density llto ceramics without phase decomposition by pressureless sintering as shown in fig1 llto powders were synthesized from lino 3 la ch 3 co 2 3 xh 2 o la oac and ta 2 o 5 precursors as an example of the invention lino 3 and la oac were dissolved in alcohol and propionic acid respectively to produce u02dc 0 4m lino 3 and 1 9m la oac solutions these solutions were then blended with an alcohol ta 2 o 5 ceramic suspension in stoichiometric quantities to achieve the target cation ratio of 5li 3la 2ta after the alcohol and propionic were removed via evaporation the mixture was then heated to achieve slow combustion within a furnace thus removing organics to produce a homogenous mixture of carbonates and oxides this mixture was then heated in excess of 800 u00b0 c to remove carbonates of lanthanum and form the mixed oxides that will eventually form llto after calcination the particle size of the synthesized and calcined powder is less than 2 u03bcm as shown in fig2 the particle size can then be further reduced by low energy milling e g ball milling prepared powder compacts or green ceramic bodies can then be placed in a closed crucible whose composition is appropriate to resist r 2 o diffusion and reaction with r 2 o.