Improvement of translucency in Al2O3 ceramics by two-step sintering technique

Powder Injection Molding of Translucent Alumina using Supercritical Fluid Debinding

“…The binder removal rate as temperature and pressure of supercritical CO 2 In a binder removal method using supercritical CO 2 , the main factor affecting the binder removal rate is the solubility between the binder and supercritical CO 2 . Supercritical CO 2 can dissolve organic materials selectively via changes in its temperature and pressure, and the binder removal rate varies greatly depending on the changes in the conditions [16].…”

“…Because complicate parts represent difficulties in fabricating it using an average molding method and need high processing cost, a powder injection molding (PIM) technology that can implement molding with low cost has been largely used [1]. As the PIM technology has a large advantage in performing low cost mass productions of metal and ceramic parts, which show difficulties in its processing, without applying secondary processing processes, applications of this technology have largely been increased in these days [2][3]. However, PIM requires many hours for removing organic binders in a green body before applying a sintering process because PIM represents a very high rate of organic binders versus powder compared to that of powder metallurgy (PM).…”

Two-Step Sintering of Ceramics

“…The high optical transmittance requires special efforts to eliminate any light scattering centres such as residual pores, grain boundaries, secondary phases and rough surfaces in the material. MgO-doped alumina ceramic sintered by TSS with lower first-step sintering exhibited improved the transmittance compared to conventionally sintered sample [40].…”

“…Ultrafine grain microstructure is crucial to enhance the mechanical properties such as hardness, wear resistance and strength. TSS successfully applied doped and pure alumina [5,24,25,[35][36][37][38][39][40][41]. Bodišová et al [36] and others [5,25,35,37,39] successfully sintered fully dense alumina (98%) with controlled grain growth (grain growth below five times than that of powder size).…”

“…Here the first step is normally a pre-coarsening step that is performed for several purposes including removal of volatile fraction and smoothing the pore channels. This method was successful to prepare fully dense nano-sized pure ZrO 2 , fully dense (>98%) alumina [38,40] and alumina-doped zirconia (7.5Al 2 O 3 .92.5ZrO 2 ) (vol.%) [8].…”