Roll Pressed LZSA Glass-Ceramics

Abstract

This work reports some experimental results regarding to a Li2O-ZrO2-SiO2-Al2O3 (LZSA) sintered glass-ceramic material obtained by roll pressing of glass powders (mean particle size ≈ 5 μm) with an added (7 wt.%) inorganic material (bentonite) as binder. The composition was characterized using chemical analysis, laser-scattering particle size analysis, DTA, XRD, thermal expansion, modulus of rupture (MOR) and deep abrasion (DA) measurements as well as density measurements and SEM observations. From the results it was verified that the glass-ceramic materials obtained by sintering and controlled crystallization, in the 850-1030°C temperature range, of glass powders, have properties and characteristics decisively better than those of other traditionally used materials. It is concluded that roll pressing technology is a potential candidate to produce sintered glassceramics for many applications, such as, for example, large sheets panels for electrical and thermal insulation.

Additive Manufacturing of Ceramics: Issues, Potentialities, and Opportunities

“…Compared to some conventional manufacturing processes such as injection molding, extrusion, or roll pressing, LOM parts exhibit moderate values of flexural strength at relatively high porosities . Values of mechanical strength for silicon nitride parts obtained by LOM of ~475 ± 34 MPa have been reported, which is comparable to silicon nitride ceramics prepared by pressureless sintering and higher than for the components fabricated by gel casting (54.5 ± 2.3 MPa) …”

“…80,81 In addition, LOM processing: (1) does not introduce an extra organic component that must be eliminated during the thermal treatment process, such as for stereolithography; (2) compared to low-temperature lamination process, the applied pressure and temperature are lower, which prevents delamination caused by an inhomogeneous pressure distribution in complex shapes; (3) does not require higher capillary forces to promote the union between adjacent tapes during thermal treatment; (4) allows the lamination of water-based green tapes, which is not successfully achieved by thermo-compression, for example. Compared to some conventional manufacturing processes such as injection molding, 83 extrusion, 84 or roll pressing, 85 LOM parts exhibit moderate values of flexural strength at relatively high porosities. 75,86 Values of mechanical strength for silicon nitride parts obtained by LOM of~475 AE 34 MPa have been reported, 87 which is comparable to silicon nitride ceramics prepared by pressureless sintering [88][89][90] and higher than for the components fabricated by gel casting (54.5 AE 2.3 MPa).…”

Estudo de composições cerâmicas à base de alumina e vitrocerâmico do sistema LZSA para obtenção de estruturas multicamadas por tape casting

“…Avaliações de características como módulo de elasticidade (E) e coeficiente de expansão térmica (CET) são indispensáveis nesta etapa [6]. Neste sentido, vitrocerâmicos do sistema LZSA (Li 2 O-ZrO 2 -SiO 2 -Al 2 O 3 ) se destacam devido à sua microestrutura composta de cristais micrométricos de espodumênio-β ss (solução sólida, Li 2 O.Al 2 O 3 .4-10SiO 2 ) e silicato de zircônio (ZrSiO 4 ), que conferem a este material densificação à baixa temperatura, baixo CET e valores de propriedades mecânicas que o tornam interessante para emprego, por exemplo, em aplicações de LTCC (low temperature co-fired ceramics) obtidos por tape casting [7][8][9][10][11][12][13][14][15].…”