Preparation of MgF₂ translucent ceramic by hot pressing sintering

Abstract

The aim of this work was to prepare MgF₂ translucent ceramic by using nanopowders as raw materials and to study its properties.The MgF₂ nanopowders were prepared using chemical precipitation and the translucent ceramics were fabricated by hot-pressing sintering in a vacuum environment. X-ray diffraction analysis showed that the powders were homogeneous with an average particles size about 13 nm. By comparing the results of transmission electron microscopy, it could be concluded that the porous structure of precursor powders could be improved by calcination. The SEM images of MgF₂ indicated that the as-prepared ceramics were well densified at 900 °C. The photo of the ceramic sample showed that high translucence is a main breakthrough in the field of MgF₂ materials preparation. For the translucent ceramic sample sintered at 900 °C, the Vickers hardness and density were 5.55 GPa and 98.74%, respectively, and its highest transmittance with thickness of 1mm reached 87% in the wavelength from 2.5 μm to 10 μm, all which made it advantageous to be a kind of infrared windows and dome materials.

Keywords

MgF₂ / nanopowders / calcination / hot-pressing / translucent ceramic

References

[1] Nandiyanto ABD, Iskandar F, Ogi T, et al. Nanometer to Submicrometer Magnesium Fluoride Particles with Controllable Morphology[J].. Langmuir, 2010, 26(14): 12260-12266.

[2] J. Am. Ceram. Soc., 1988, 71(3

[3] Chen SC, Min HH, Sheng JY. Effects of Calcination and Hot- Pressing Temperatures of Magnesium Fluoride Powder on Its Optical Property[J].. Jpn. J. Appl. Phys., 1990, 29(12): 2751-2754.

[4] Chang CS, Hon MH, Yang SJ. The Optical Properties of Hot-pressed Magnesium Fluoride and Single-crystal Magnesium Fluoride in the 0.1 to 9.0 μm Range[J].. J. Mater. Sci., 1991, 26(6): 1627-1630.

[5] Recker K, Leckebusch R. Vapor Phase Growth of Single Crystals of High-Melting Fluorides. I. Magnesium Fluoride[J].. J. Cryst. Growth, 1969, 5(2): 125-31.

[6] Rice HH, Garey MJ. Sintering of Magnesium Fluoride[J].. Am. Ceram. Soc. Bull., 1967, 46(12): 1149-53.

[7] MALTSEV MV, Udalova LV, Goryachev AY, et al. Fabrication of Optical-ceramic Preforms without Mechanical Treatment[J].. Soviet J.Opt. Technol., 1993, 60(1): 67-69.

[8] Shirakawa Y, Harada T, Sashida N, et al. Preparation of MgF2 Sintered Body by Normal Sintering Combined with Capsule-free Hotisostatic Pressing Treatment[J].. Nippon seramikkusu kyokai gakujutsu ronbunshi, 1999, 107(12): 1137-1139.

[9] Nofar M, Madaah HHR, Shivaee HA. The Dependency of Optical Properties on Density for Hot Pressed MgF2[J].. Infrared Phys. Technol., 2008, 51(6): 546-549.

[10] Buckner DA, Hafner HC, Kreidl NJ. Hot-Pressing Magnesium Fluoride[J].. J. Am. Ceram. Soc., 1962, 45(9): 435-438.

[11] Chen SC, Min HH. Texture Effect of Hot-pressed Magnesium Fluoride on Optical Transmittance[J].. Mater. Chem. Phys., 2003 27-32.

[12] Ikesue A, Furusato I, Kamata K. Fabrication of Polycrystalline, Transparent YAG Ceramics by a Solid-State Reaction Method[J].. J. Am. Ceram. Soc., 1995, 78(1): 225-228.

[13] Ikesue A, Kinoshita T, Kamata K, et al. Fabrication and Optical Properties of High-Performance Polycrystalline Nd:YAG Ceramics for Solid-State Lasers[J].. J. Am. Ceram. Soc., 1995, 78(4): 1033-1040.

[14] Kopylov YL, Kravchenko VB, Komarov AA, et al. Nd:Y2O3 Nanopowders for Laser Ceramics[J].. Opt. Mater., 2007, 29(10): 1236-1239.

[15] Zhang J, Wang S, An L, et al. Infrared to Visible Upconversion Luminescence in Er³⁺: Y23 Transparent Ceramics[J]. J. Lumines., 2007, 122-123: 8-10.