Colloidal Processing of Glass–Ceramics for Laminated Object Manufacturing

Abstract

Green tapes of Li 2 O-ZrO 2 -SiO 2 -Al 2 O 3 (LZSA) parent glass were produced by aqueous tape casting as the starting material for the laminated object manufacturing (LOM) process. The rheological behavior of the powder suspensions in aqueous media, as well as the mechanical properties of the cast tapes, was evaluated. According to n potential measurements, the LZSA glass powder particles showed acid surface characteristics and an IEP of around 4 when in aqueous media. The critical volume fraction of solids was about 72 wt% (27 vol%), which hindered the processability of more concentrated slurries. The glass particles also showed an anisometric profile, which contributed to an increase in the interactions between particles during flow. Therefore, the suspensions could not be processed at high solids loadings. Aqueous-based glass suspensions were also characterized by shear thickening after the addition of dispersants. Three slurry compositions were formulated, suitable green tapes were cast, and tapes were successfully laminated by LOM to a gear wheel geometry. A higher tensile strength of the green tapes corresponded to a higher tensile strength of the laminates. Thermal treatment was then applied to the laminates: pyrolysis at 5251C, sintering at 7001C for 1 h, and crystallization at 8501C for 30 min. A 20% volumetric shrinkage was observed, but no surface flaws or inhomogeneous areas were detected. The sintered part maintained the curved edges and internal profile after heat treatment.

Corrugated glass–ceramics from LZSA cast tapes

“…The remarkable influence of the slip composition on the rheological behavior of the LZSA aqueous suspensions for tape casting has already been reported (Gomes et al, 2009). For increasing solids loading (from 50 to 70 wt.%), the suspension behavior turns from shear thinning to shear thickening.…”

“…Additionally, this system can be processed at low sintering and crystallization temperatures (∼700 and ∼800 • C, respectively). Sintered LZSA glass-ceramics have been processed by many techniques such as roll pressing (Reitz et al, 2006), extrusion (Bertan et al, 2009), injection molding (Giassi et al, 2006), tape casting (Gomes et al, 2009), and laminated object manufacturing (Gomes et al, 2008).…”

Additive Manufacturing of Ceramic‐Based Materials

“…Received: January 16,2014 Final Version: February 27, 2014 C [284] ZrC [160] TiC/Ni [289] Al 2 O 3 -ZrO 2 [191] Polymer-derived ceramics: see present work Functional ceramics BaTiO 3 [40,41] PZT [89] PZT [211,223,239] BaTiO 3 [150] SiO 2 -Al 2 O 3 -RO-glass [269] PZT [37,[45][46][47] BaTiO 3 [115] SiCN [225] PZT [145,146] LZSA-Glass [272] TiO 2 [43,44] PMN [192] PZT [282] LSMO/YBCO [48] LiFePO 4 [170] Li 4 Ti 5 O 12 BaZrO 3 , SrTiO 3 , BaMn 2 Al 10 O 19À x [193] ITO [119] ZnO [119,187] La(Mg 0.5 , Ti 0.5 )O 3 [167,188] Zr 0.8 Sn 0.2 TiO 4 [188] TiO 2 [119] Bioceramics HA [50,66,67,[69][70][71][72] Apatite-Mullite [107][108]…”

“…The green sheet tensile strength of single layers and laminates was investigated and applicability for the LOM process was proved. [272] The LOM cutting parameters (cutting speed and laser power) were adjusted to the LZSA system and maximum cut profundity of 220 mm was determined. [259] Their sintering behavior was characterized before and after binder burnout (750°C) and sintering (850°C), which led to a new phase formation of b-spodumene and lithium metasilicate.…”

Tape casting of strontium and cobalt doped lanthanum chromite suspensions

“…15 Tape casting is a well-established technique for large-scale fabrication of ceramic products with large areas and small thicknesses, ranging from 50 to 500 m, such as substrates, 16 electronic components, 17 solid oxide fuel cell components 18 and multilayered structures. 19 The use of appropriate additives is essential to achieve homogeneous, dense and flexible green tapes with high strength.…”