Molybdenum alloy containing antioxidant composite coating and preparation method thereof

A technology of composite coating and molybdenum alloy, which is applied in the direction of coating, metal material coating process, solid-state diffusion coating, etc., can solve the problems of large difference in thermal expansion coefficient, easy cracks at the joint, poor oxidation resistance at medium temperature, etc. , to achieve the effects of reducing the difference in thermal expansion coefficient, good bonding, and favorable erosion resistance

Active Publication Date: 2021-06-25
NANCHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

According to the research status at home and abroad, the main problems of the silicide coating prepared on the surface of molybdenum alloy include: (1) single MoSi 2 Although the coating has excellent high-temperature oxidation resistance, it has poor medium-temperature oxidation resistance, and "Pesting" pulverization and oxidation will occur at 400-600 °C; (2) MoSi 2 The thermal expansion coefficient difference between the coating and the substrate is large, and cracks are prone to occur inside the coating and at the junction with the substrate interface, resulting in failure of the coating and poor thermal shock resistance; (3) MoSi 2 SiO formed on the surface after coating oxidation 2 Membrane has good fluidity at high temperature, so the ability to resist gas scour is insufficient
However, there is no mature method to solve the above problems at the same time

Method used

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  • Molybdenum alloy containing antioxidant composite coating and preparation method thereof
  • Molybdenum alloy containing antioxidant composite coating and preparation method thereof
  • Molybdenum alloy containing antioxidant composite coating and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Step 1: Preparation of Mo-based alloy

[0032] According to the proportion of 85at% Mo, 15at% Cr, the planetary ball mill is used for wet grinding, the ball-to-material ratio is 5:1, the speed is 120r / min, the ball milling time is 30h, and the powder is placed in a vacuum drying box after ball milling. drying. The dried powder is then put into a cold isostatic pressing die for compression molding. The pressed samples were sintered under low pressure at 1600°C and 0.6Mpa for 3 hours to prepare the Mo-15Cr matrix alloy.

[0033] Step 2: Prepare (Mo,X)Si on the surface of the alloy obtained in Step 1 2 -(Cr,X)Si 2 base composite coating

[0034] The surface of the alloy was ground and polished step by step with 240#, 400#, 600# and 1000# silicon carbide sandpaper, ultrasonically cleaned in absolute ethanol and then dried. Place the treated sample in an alumina crucible, place it in a tube furnace, and feed NH into the furnace tube 3 , the flow rate is 200ml / min, and ...

Embodiment 2

[0036] Step 1: Preparation of Mo-based alloy

[0037] According to the proportion of 75at% Mo, 25at% Cr, the planetary ball mill is used for wet grinding, the ball-to-material ratio is 5:1, the speed is 120r / min, the ball milling time is 30h, and the powder is placed in a vacuum drying box after ball milling. drying. The dried powder is then put into a cold isostatic pressing die for compression molding. The pressed samples were sintered under low pressure at 1600°C and 0.6Mpa for 3 hours to prepare the Mo-25Cr matrix alloy.

[0038] Step 2: Prepare (Mo,X)Si on the surface of the alloy obtained in Step 1 2 -(Cr,X)Si 2 base composite coating

[0039] The surface of the alloy was ground and polished step by step with 240#, 400#, 600# and 1000# silicon carbide sandpaper, ultrasonically cleaned in absolute ethanol and then dried. Place the treated sample in an alumina crucible, place it in a tube furnace, and feed NH into the furnace tube 3 , the flow rate is 200ml / min, and ...

Embodiment 3

[0041] Step 1: Preparation of Mo-based alloy

[0042] Carry out batching by 30at%Cr, 10at%Al, 5at%W, the balance is the ratio of Mo, adopt planetary ball mill to carry out wet grinding, ball material ratio 5:1, rotating speed 120r / min, ball milling time 30h, after ball milling finishes The powder is dried in a vacuum oven. The dried powder is then put into a cold isostatic pressing die for compression molding. The pressed samples were sintered under low pressure at 1600°C and 0.6Mpa for 3 hours to prepare the Mo-30Cr-10Al-5W matrix alloy.

[0043] Step 2: Prepare (Mo,X)Si on the surface of the alloy obtained in Step 1 2 -(Cr,X)Si 2 base composite coating

[0044] The surface of the molybdenum matrix alloy was ground and polished step by step with 240#, 400#, 600# and 1000# silicon carbide sandpaper, ultrasonically cleaned in absolute ethanol and then dried. Place the treated sample in an alumina crucible, place it in a tube furnace, and feed NH into the furnace tube 3 , ...

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Abstract

The invention discloses a molybdenum alloy containing an antioxidant composite coating and a preparation method thereof, and relates to the technical field of high-temperature alloy thermal protection. The molybdenum alloy containing the antioxidant composite coating comprises a molybdenum alloy matrix and a composite coating on the surface of the molybdenum alloy matrix; the composite coating at least comprises a (Mo, X)Si2 phase and a (Cr, X)Si2 phase; the composite coating can further have a double-layer structure; the outer layer at least comprises the (Mo, X)Si2 phase and the (Cr, X)Si2 phase; the inner layer at least comprises a (Mo, X)5Si3 phase; X in the (Mo, X)Si2 represents Cr, Ti or W; and X in the (Cr, X)Si2 represents Mo, Ti or W. The preparation method comprises the following steps: preparing the molybdenum alloy matrix and preparing the composite coating on the surface of the alloy by adopting co-permeation; and the molybdenum alloy protected by the (Mo, X)Si2-(Cr, X)Si2-based composite coating is prepared by adopting a method for combining matrix alloying and surface modification, an alloying and compounding method and a multi-layer structure combined modification silicide coating. The molybdenum alloy has excellent medium-temperature and high-temperature oxidation resistance.

Description

technical field [0001] The invention relates to the technical field of high-temperature alloy thermal protection, in particular to a molybdenum alloy containing an anti-oxidation composite coating and a preparation method thereof. Background technique [0002] Molybdenum and its alloys have the advantages of high melting point, low resistivity, high thermal conductivity, low thermal expansion coefficient and high high temperature strength, and are key materials for the preparation of rocket nozzles, nozzle throat linings, radiation shields, heat shields and heating elements. It has broad application prospects in aerospace, nuclear industry, machinery, metallurgy and other fields. However, molybdenum and molybdenum alloys will be quickly oxidized into volatile MoO in the air environment above 600 °C. 3 , which seriously restricts its use as a high-temperature material. [0003] At present, the high-temperature anti-oxidation methods of molybdenum mainly include alloying and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C10/44C22C27/04C22C1/04C23C10/52
CPCC23C10/44C22C27/04C22C1/045C23C10/52
Inventor 谭敦强易志强唐晔熊伟龙文海强
Owner NANCHANG UNIV
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