Alumina composite monocrystal high-temperature tungsten metallization method

A technology of compounding single crystal and alumina, applied in the field of high temperature tungsten metallization of alumina compound single crystal, can solve the problems of high impurity content and uneven composition of metallized layer, and achieve dense metallized layer, uniform quality and uniform thickness. Effect

Active Publication Date: 2014-04-09
GRIMAT ENG INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This kind of powder is easy to cause defects such as uneven composition of the metallization layer and high impurity content.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] This process is used for high temperature tungsten metallization of alumina composite single crystals in thermionic fuel elements. Among them, the material of alumina composite single crystal is alumina composite single crystal doped with yttrium oxide, the mass percentage of yttrium oxide is 3.5wt%, single crystal size: outer diameter Ф14.5mm, inner diameter Ф9.6mm, height 10mm, metal The chemical quality was evaluated by the sealing airtightness of alumina composite single crystal and niobium alloy.

[0034] (1) Pretreatment of alumina composite single crystal

[0035] Grind and polish the surface of the aluminum oxide composite single crystal to be welded so that the roughness Ra is 0.7 μm. Use cleaning agent to ultrasonically clean for 20 minutes, and rinse the cleaning agent with deionized water until there is no cleaning agent foam. The alumina composite single crystal was boiled in deionized water for 8 minutes, dehydrated with alcohol and dried in the air. In ...

Embodiment 2

[0049] This process is used for high temperature tungsten metallization of alumina composite single crystals in thermionic fuel elements. The composition of the alumina composite single crystal is the same as in Example 1, but the size is relatively large. The outer diameter of the single crystal is Ф36.5mm, the inner diameter is Ф31.5mm, and the height is 10.0mm. Confidentiality is evaluated.

[0050] (1) Pretreatment of alumina composite single crystal

[0051] The surface of the aluminum oxide composite single crystal to be welded is ground and then polished so that the roughness Ra is 0.5 μm. Use cleaning agent to ultrasonically clean for 30 minutes, and rinse the cleaning agent with deionized water until there is no cleaning agent foam. Boil the alumina composite single crystal in deionized water for 5 minutes, dehydrate it with alcohol, dry it in the air, and burn it in a hydrogen furnace at high temperature. The bisque firing process is: sintering temperature 1000°C;...

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Abstract

The invention discloses an alumina composite monocrystal high-temperature tungsten metallization method, belonging to the technical field of ceramic-metal sealing. The metallization process is completed by adopting tungsten-yttrium oxide composite powder on the alumina composite monocrystal surface through double paste application and double sintering processes. The metallization method comprises the following steps of: firstly, grinding, polishing and cleaning the alumina composite monocrystal surface; blending the tungsten-yttrium oxide composite powder into a paste by using a guncotton solution, uniformly applying the paste to the alumina composite monocrystal surface to the coating thickness of 30-40 mu m, and sintering the alumina composite monocrystal surface at low temperature; and applying the paste for the second time to the thickness of 20-30 mu m, and sintering the alumina composite monocrystal surface at high temperature. The metallization process has the characteristics of adopting the tungsten-yttrium oxide composite powder as metallization powder and completing metallization paste application in two times. The metalized layer prepared by the metallization process has strong binding force with alumina composite monocrystal, does not peel and has uniform thickness, and reliable guarantee is provided for high-airtight high-strength sealing between alumina composite monocrystal and metal in later period.

Description

technical field [0001] The invention relates to a high-temperature metallization method of alumina composite single crystal tungsten, belonging to the technical field of ceramic-metal heterogeneous material connection. Background technique [0002] The metallization modification of the welded surface of alumina composite single crystal is the premise of its reliable sealing with metal. In the conventional molybdenum-manganese metallization process, the sintering temperature is generally around 1400°C. If the temperature exceeds this temperature during later welding or use, the glass phase in the metallization layer will flow and damage the metallization layer, thus affecting the ceramic-metal seal. properties such as joint strength and sealing air tightness. Moreover, the lower metallization sintering temperature also limits the selection of high-temperature brazing material when the alumina composite single crystal is sealed with the metal, which directly limits the high-t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B37/02
Inventor 陆艳杰张小勇
Owner GRIMAT ENG INST CO LTD
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