Fabrication of injection moulded translucent alumina ceramics via pressureless sintering

Abstract

In this work, injection moulding and pressureless sintering in hydrogen were applied to manufacture translucent alumina ceramics. Excellent rheological properties of the feedstocks for injection moulding were obtained through a method of powder pretreatment with stearic acid induced by ball milling. Optimum solid loading was confirmed in terms of rheological data and porous properties. The average grain size of the sintered body is 30-50 mm, with no significant pores and abnormal grain growth observed. The real inline transmission is higher and more stable than those via other forming technologies and pressureless sintering reported in previous literatures. As a result, translucent alumina components with small size and high precision were fabricated in such a stable, efficient and low cost route.

Yield stress modelling of doped alumina suspensions for applications in freeze granulation: towards dry pressed transparent ceramics

“…In particular for ceramics, suspension rheology is crucial in a variety of processing steps such as slip casting, [1][2][3] injection moulding, 4,5 screen printing, 6 tape casting 7 and extrusion. 8 Also for dry forming processes, the quality of the granules depends on the suspension rheology during spray drying.…”

Investigation of nanosized alumina‐binder feedstock rheology for ceramics injection molding (CIM) and survey spark plasma sintering of output green body to obtain transparent alumina

“…According to this figure, the maximum visible transmission has been about ∼35% at wavelength 650 nm. As‐obtained visible transmission was more than research that used pressure less sintering at 1800°C under H 2 atmosphere ( T = 12%) or co‐using slip casting and SPS method ( T = 28%) 5,25,26 . The theoretical transmission of alumina (based on Rayleigh–Gans–Debye theory) with zero porosity and grain boundary and thickness of 1.5 mm was ∼50% at a wavelength of 650 nm.…”

“…The optimal temperature of the materials to have a pseudoplastic behavior by this group was reported at 170°C. Liu et al 5 . examined the fluidity behavior of a feed containing commercial alumina powder with a mean grain size of .35 μm and a binder system consisting of pp, polyethylene vinyl acetate copolymer, paraffin wax, stearic acid dispersant agent, and dibutyl phthalate plasticizer with portions of 10, 60, 15, and 5 vol.%, respectively.…”

“…3 To have a green part with no or minimal defects, the optimal feed for the CIM device is a feed with pseudoplastic rheological behavior. Wei et al 4 investigated the fluidity behavior of alumina powder with a mean particle size of 400 nm alongside polypropylene (pp), paraffin wax, and stearic acid with an 85-15 wt.% ratio of powder to the binder at 140-170 • C. The optimal temperature of the materials to have a pseudoplastic behavior by this group was reported at 170 • C. Liu et al 5 examined the fluidity behavior of a feed containing commercial alumina powder with a mean grain size of .35 μm and a binder system consisting of pp, polyethylene vinyl acetate copolymer, paraffin wax, stearic acid dispersant agent, and dibutyl phthalate plasticizer with portions of 10, 60, 15, and 5 vol.%, respectively. Various portions of alumina powder from 52 to 58 vol.% were examined in that research to obtain the optimal percentage.…”

High-purity Ti2AlC Powder: Preparation and Application in Ag-based Electrical Contact Materials

“…These techniques, however, cost highly with complex process, and produce Ti 2 AlC with many impure phases such as TiC, Ti-Al compounds, and Ti 3 AlC 2 . In contrast, the pressureless sintering technique (PLS) is simple, efficient, and low-cost [23] , which is more meaningful for the practical application. In addition, the preparation, microstructure, interface bonding, and electrical contacting property of composite can be largely affected by the wettability between reinforcement and Ag matrix.…”