Multi-element negative-expansion tungstate layer coated on microcrystal ceramics and its preparing process

Abstract

A coated layer of ceramics contains cubic-phase ZrW2O8 sosoloid microcrystal doped by 3-valence metal element, Mo, or P and non-crystal glass, phase, and is prepared through preparing wet gel of multi-element tungstate, centrifugal coating on the zero-expansion quartz glass substrate several times, and heat treating. Its advantage is negative expansion coefficient (-2.0- -0.3X10 to the power -6 / deg.C for -20-80 deg.C).

Description

Technical field: [0001] The invention relates to a negative expansion ceramic coating and a preparation method thereof, in particular to a stable multi-element tungstate negative expansion microcrystalline ceramic coating and a preparation method thereof. The ceramic coating can be used to make temperature-compensating coating materials for electronic or optical components, especially temperature-compensating negative-expansion coatings for non-temperature-sensitive fiber grating devices. Background technique: [0002] Negative expansion materials have always received attention due to their shrinking behavior when heated. Many materials with negative expansion behavior have been discovered, such as aluminosilicate Mg 2 Al 4 Si 5 O 18 , LiAlSiO 4 And zeolite, phosphate NaZr 2 (PO 4 ) 3 , Zr(V x P 2-x )O 7 Wait. The thermal expansion behavior of these materials tends to be anisotropic, that is, contraction occurs in a certain crystallographic direction, while expansion occurs in ot...

AI Technical Summary

Problems solved by technology

In the 1970s, former Soviet scientists studied tungstate, especially the anti-cubic phase ZrW 2 o 8 The synthesis has been intensively studied, but the cubic phase ZrW 2 o 8 It is only thermodynamically stable in a narrow temperature range around 1100 °C, the preparation process conditions are quite harsh, the synthesis is difficult and not stable, and it is difficult to obtain a single pure crystal phase, so it has not been paid attention to and applied

However, it is difficult to sinter this kind of material to be dense. Although Merkel et al. have described in detail the use of various sintering aids to increase the density in the patent specification, the sintering process is complicated and difficult to control, and the formed composite negative expansion material is also prone to cracking.

In addition, the interface contact between the negative expansion substrate material and the fiber bragg grating (FBG) device is also limited to the connecting solder joints, the interface stress is easy to hesitant, and no reliable compensation effect can be obtained.

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