Electro-conducting glass-ceramics produced by ion-exchange and reduction treatments

ABSTRACTA technique has been developed for the synthesis and near-net-shape forming of celsian glass-ceramics. This technique involves ion exchange of zeolite precursor powders, heat treatment of the powders to temperatures between 800–90°C to form a glassy phase during which the samples are formed under low stresses (<20 MPa). Upon further heat treatment to about 1000°C, crystallization occurs and the amorphous formed body is transformed to the celsian ceramic phase. Using this technique, and through the addition of monoclinic seed particles as well as a mineralizer, monoclinic celsian was produced at temperatures as low as 1000°C at heat treatment times of less than one hour. This forming technique also resulted in a significant reduction in the porosity of the ceramic bodies compared to free-sintered samples.

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Effect of crystalline phase on the nanoparticle growth in glass-ceramics

Journal of Materials Research ◽

10.1557/jmr.1994.2480 ◽

1994 ◽

Vol 9 (10) ◽

pp. 2480-2483 ◽

Cited By ~ 7

Author(s):

T.K. Kundu ◽

D. Chakravorty

Keyword(s):

Ion Exchange ◽

Exchange Reaction ◽

Glass Ceramic ◽

Crystalline Phase ◽

Glass Ceramics ◽

Silver Particles ◽

Reduction Behavior ◽

Nanoparticle Growth ◽

Reduction Treatment ◽

Ion Exchange Reaction

Nanometer-sized silver particles with diameters in the range 4.3 to 11.5 nm have been grown within a glass-ceramic containing BaTiO3 by just subjecting the former to an alkali/silver ion exchange reaction. A reduction treatment in hydrogen is, however, shown to be necessary for such growth in glass-ceramics having crystalline phases such as BaTiSiO5, Zn2SiO4, and Li4P2O7, respectively. The possible presence of Ti3+ ions in the BaTiO3 phase is believed to cause such a difference in the reduction behavior of these composites.

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Preparation and Characterization of High-Strength Glass-Ceramics via Ion-Exchange Method

Materials ◽

10.3390/ma14195477 ◽

2021 ◽

Vol 14 (19) ◽

pp. 5477

Author(s):

Jianwei Lu ◽

Haifeng Wang ◽

Juanjuan Zhu ◽

Qiuju Zheng ◽

Linfeng Ding ◽

...

Keyword(s):

Mechanical Properties ◽

Solid Solution ◽

Ion Exchange ◽

Flexural Strength ◽

Vickers Hardness ◽

Glass Ceramics ◽

High Strength ◽

Aluminosilicate Glass ◽

Exchange Method ◽

The Impact

Lithium aluminosilicate glass-ceramics (LAS GCs) are ideal shell materials for mobile phones; however, the mechanical properties of LAS GCs are comparatively lower than that of other shell materials. In this work, the impact of TiO2/(TiO2 + ZrO2) ratio on properties of LAS GCs was studied and the ion-exchange methods were applied to improve the mechanical properties of LAS GCs. The results show that LAS GCs with TiO2/(TiO2 + ZrO2) = 1/2 exhibit the best flexural strength (109 MPa) and Vickers hardness (525 Kg/mm2). The as-prepared glass was nucleated at 560 °C for 1 h and crystallized at 720 °C for 0.5 h. The main crystalline phases of LAS GCs are β-quartz solid solution, β-spodumene solid solution, and Li2SiO3. Moreover, the flexural strength and Vickers hardness of LAS GCs with TiO2/(TiO2 + ZrO2) = 1/2 further increased to 356 MPa and 838 Kg/mm2 after an ion-exchange at 420 °C for 6 h in pure KNO3 molten salt. The LAS GCs with enhanced mechanical strength have the potential to be applied as mobile phone back panels.

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