阅读说明：本技术 高韧性低导热的金属基-陶瓷复合涂层及其制备方法和应用 (High-toughness low-heat-conductivity metal-based ceramic composite coating and preparation method and application thereof ) 是由 周正 韩凤熙 姚海华 吴旭 谈震 郭星晔 邵蔚 王国红 贺定勇 于 2020-06-10 设计创作，主要内容包括：本发明公开了一种高韧性低导热的金属基-陶瓷复合涂层及其制备方法和应用,其制备方法包括,将喷涂在金属基体表面的金属基-陶瓷复合涂层进行热处理,在金属基非晶合金与陶瓷相之间形成界面层,从而在增加界面层热阻的基础上增强其韧性。本发明通过优化热处理工艺,能有效降低复合涂层的导热,增加其韧性；其制备方法简单,仅通过简单的热处理即能在提升金属基-陶瓷复合涂层的隔热效果的基础上增强其韧性,所制得的高韧性低导热金属基-陶瓷复合涂层综合性能良好,在隔热防护领域应用前景广阔。(The invention discloses a high-toughness low-heat-conduction metal-based ceramic composite coating, and a preparation method and application thereof. By optimizing the heat treatment process, the heat conduction of the composite coating can be effectively reduced, and the toughness of the composite coating is improved; the preparation method is simple, the toughness of the metal-based ceramic composite coating can be enhanced on the basis of improving the heat insulation effect of the metal-based ceramic composite coating only through simple heat treatment, and the prepared high-toughness low-heat-conductivity metal-based ceramic composite coating has good comprehensive performance and wide application prospect in the field of heat insulation protection.)

1. A preparation method of a metal-based ceramic composite coating with high toughness and low heat conduction is characterized in that,

the metal-based ceramic composite coating sprayed on the surface of the metal matrix is subjected to heat treatment to form an interface layer between the metal-based amorphous alloy and the ceramic phase, so that the toughness of the interface layer is enhanced on the basis of increasing the thermal resistance of the interface layer.

2. The production method according to claim 1,

the temperature of the heat treatment is 250-620 ℃;

and/or the time of the heat treatment is 10-300 min.

3. The production method according to claim 1,

the heat treatment is carried out in an inert atmosphere;

preferably, the inert atmosphere is an argon atmosphere or a nitrogen atmosphere.

4. The production method according to any one of claims 1 to 3,

the thickness of the interface layer is 5 to 30nm, preferably 7 to 20 nm.

5. The production method according to any one of claims 1 to 4,

the heat treatment is specifically that the annealing is carried out for 5-10min at the temperature of 250-300 ℃ and then the annealing is carried out for 10-300min at the temperature of 350-620 ℃.

6. The production method according to any one of claims 1 to 5,

the metal matrix-ceramic composite coating is prepared by adopting an atmospheric plasma spraying method, and specifically comprises the following steps:

respectively preparing metal-based amorphous alloy powder and ceramic powder by adopting a nitrogen atomization method and an agglomeration sintering method, uniformly mixing the metal-based amorphous alloy powder and the ceramic powder in proportion to prepare composite powder, then sequentially removing a surface oxidation film, cleaning dirt and carrying out sand blasting treatment on a metal matrix, and finally preparing a metal-based ceramic composite coating on the surface of the metal matrix by adopting an atmospheric plasma spraying process on the composite powder.

7. The production method according to claim 6,

the specific process parameters of the atmospheric plasma spraying process are as follows: the current is 500-700A, the argon flow is 30-50L/min, the hydrogen flow is 6-8L/min, the powder delivery rate is 42-60g/min, and the spraying distance is 110-140 mm.

8. The production method according to any one of claims 1 to 7,

the metal-based amorphous alloy is an iron-based amorphous alloy containing chromium, niobium, boron and silicon;

and/or the ceramic phase contains Y₂O₃6-8 wt% YSZ;

and/or the thickness of the metal matrix-ceramic composite coating is 360-450 mu m.

9. The metal matrix-ceramic composite coating with high toughness and low thermal conductivity prepared by the preparation method of any one of claims 1-8.

10. Use of the high toughness, low thermal conductivity metal matrix-ceramic composite coating of claim 9 in the field of thermal protection.

Technical Field

The invention belongs to the field of heat insulation protection in surface engineering, and particularly relates to a high-toughness low-heat-conductivity metal-based ceramic composite coating, and a preparation method and application thereof.

Background

In recent years, metal-based thermal barrier coatings have attracted much attention due to their good toughness, better thermal expansion matching with metal substrates, simple processing, and low cost.

Chinese patent applications such as 201410128869.4, 201610024163.2, 201610024343.0 and 201610025620.X disclose methods for preparing iron-based amorphous alloys for thermal protection and coatings thereof, confirming the feasibility of metal-based thermal barrier coatings. However, due to the metastable intrinsic property of the amorphous alloy, the application of the amorphous alloy at medium and high temperature is greatly limited; in view of this, further optimization is carried out on the basis of the original Fe-based amorphous heat-insulating coating material, and the ceramic phase is introduced to be dispersed and distributed on the amorphous alloy matrix phase to form the composite coating, so that the heat conductivity of the composite coating is reduced.

Although the introduction of the ceramic phase can significantly reduce the thermal conductivity of the composite coating, the brittleness inherent in the introduced ceramic phase makes the composite coating easily induce high-frequency thermal fatigue under the action of severe high temperature and mechanical load, and the cracking, peeling, failure and the like caused by the high-frequency thermal fatigue are not negligible.

In summary, how to enhance the toughness of the metal matrix-ceramic composite coating on the basis of improving the heat insulation effect of the metal matrix-ceramic composite coating is a key technical problem to be solved urgently by the technical personnel in the field.

In view of this, the invention is particularly proposed.

Disclosure of Invention

The invention makes up the defects of the prior art and provides the metal-based ceramic composite coating with high toughness and low heat conductivity as well as the preparation method and the application thereof.

The invention adopts the following technical scheme:

a process for preparing the high-toughness low-heat-conductivity metal-base ceramic composite coating includes such steps as heat treating the metal-base ceramic composite coating sprayed on the surface of metal substrate to form an interface layer between the metal-base amorphous alloy and ceramic phase, so increasing the thermal resistance of said interface layer and increasing its toughness.

Specifically, by forming an interfacial layer between the metal-based amorphous alloy and the ceramic phase by heat treatment, the reaction interfacial layer is thicker and the connection between the two is better, unlike pure mechanical bonding, thereby increasing the toughness thereof.

In the above technical solution, the temperature of the heat treatment is 250-620 ℃.

Specifically, if the heat treatment temperature is too low, the movement of atoms is relatively low; when the heat treatment temperature is higher than the crystallization temperature of the amorphous system, the amorphous starts to crystallize and the thermal conductivity increases.

In the technical scheme, the time of the heat treatment is 10-300 min.

In the above technical solution, the heat treatment is performed in an inert atmosphere.

The heat treatment is carried out in the inert atmosphere, so that the generation of oxides of Fe element and the like under the heating condition can be effectively avoided, and the comprehensive performance of the alloy is reduced.

Preferably, in the above technical solution, the inert atmosphere is an argon atmosphere or a nitrogen atmosphere.

Further, in the above technical means, the thickness of the interface layer is 5 to 30nm, preferably 7 to 20 nm.

Specifically, when the thickness of the interface layer is too thin, the toughening and thermal conductivity reduction effects are not obvious because the interface layer is also amorphous silicon oxide; when the interface layer is too thick, the amorphous element is deviated, the performance of the amorphous phase is reduced, and the brittleness of the interface layer is obviously increased.

Furthermore, in the above technical solution, the heat treatment is specifically performed by pre-annealing at 300 ℃ of 250-300 ℃ for 5-10min, and then annealing at 620 ℃ of 350-620 ℃ for 10-300 min.

In a preferred embodiment, the metal matrix-ceramic composite coating is prepared by an atmospheric plasma spraying method, and specifically comprises the following steps:

respectively preparing metal-based amorphous alloy powder and ceramic powder by adopting a nitrogen atomization method and an agglomeration sintering method, uniformly mixing the metal-based amorphous alloy powder and the ceramic powder in proportion to prepare composite powder, then sequentially removing a surface oxidation film, cleaning dirt and carrying out sand blasting treatment on a metal matrix, and finally preparing a metal-based ceramic composite coating on the surface of the metal matrix by adopting an atmospheric plasma spraying process on the composite powder.

Specifically, in the above technical solution, the specific process parameters of the atmospheric plasma spraying process are as follows: the current is 500-700A, the argon flow is 30-50L/min, the hydrogen flow is 6-8L/min, the powder delivery rate is 42-60g/min, and the spraying distance is 110-140 mm.

In detail, in the above technical solution, the metal-based amorphous alloy is an iron-based amorphous alloy containing chromium, niobium, boron and silicon.

Specifically, the composition of the raw materials of the metal-based amorphous alloy is as follows: 21.34-26.57% of ferroboron, 10.8-13.6% of ferroniobium, 1-6% of ferrosilicon, 14-17% of pure chromium and 39-47% of pure iron.

In detail, in the above technical scheme, the ceramic phase contains Y₂O₃6-8 wt% YSZ.

In detail, in the above technical solution, the thickness of the metal matrix-ceramic composite coating is 360-450 μm.

The metal matrix-ceramic composite coating obtained by the method has lower thermal conductivity and better fracture toughness; the improvement of the heat insulation performance and the toughness of the composite coating is beneficial to a reasonable heat treatment process besides the advantages of components.

Because the sensitivity of the amorphous alloy structure and the regulation and control of the heat treatment temperature and time are crucial, how to promote the generation of the interface layer and simultaneously not change the amorphous phase structure and the ceramic phase structure are the key points of the invention, the heat treatment temperature and time are regulated and controlled according to the component characteristics of the alloy system, so that part of Si element is diffused to the interface and reacts with the ceramic phase to generate a silicon-rich oxide interface layer on the premise that the metal-based amorphous alloy phase does not crystallize.

Specifically, the generation of the silicon-rich oxide interface layer can increase the scattering effect on heat transfer phonons, and meanwhile, the oxide interface has self thermal resistance, so that the overall thermal conductivity of the composite coating can be effectively reduced, and the heat insulation capability is improved; in addition, due to the brittleness of the ceramic phase, the introduction of the ceramic phase inevitably brings about the reduction of the toughness of the metal-based coating, and an interface reaction layer with proper thickness can well relieve the deterioration effect, but an excessively thick interface layer can cause the obvious change of amorphous alloy components and further generate crystallization, so that the composite coating is embrittled integrally. Therefore, the growth and thickness of the interface layer are the key points for reducing thermal conductivity and improving toughness, and the heat treatment temperature and time aiming at the characteristics of the material are the methods for realizing the effect, and the reasonable regulation and control technology is of great importance and can not be obtained through only limited tests.

On the other hand, the invention provides the metal-based ceramic composite coating with high toughness and low heat conductivity, which is prepared by the preparation method.

The invention also provides application of the high-toughness low-heat-conductivity metal matrix-ceramic composite coating in the field of heat insulation and protection.

The invention has the following advantages:

according to the invention, an interface layer is formed between the metal-based amorphous alloy and the ceramic phase through heat treatment, which is different from pure mechanical combination, and the reaction interface layer can effectively reduce the heat conduction of the metal-based amorphous alloy and the ceramic phase, so that the connection between the metal-based amorphous alloy and the ceramic phase is better, and the toughness of the metal-based amorphous alloy and the ceramic phase is improved; the preparation method is simple, the toughness of the metal-based ceramic composite coating can be enhanced on the basis of improving the heat insulation effect of the metal-based ceramic composite coating only through simple heat treatment, and the prepared high-toughness low-heat-conductivity metal-based ceramic composite coating has good comprehensive performance and wide application prospect in the field of heat insulation protection.

Drawings

FIG. 1 is an XRD spectrum of a metal matrix-ceramic composite coating prepared in example 3 of the present invention;

FIG. 2 is a TEM photograph of the metal matrix-ceramic composite coating prepared in example 3 of the present invention.

Detailed Description

The following describes the embodiments of the present invention in further detail with reference to specific examples.

The following examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention.

The experimental procedures used in the following examples are conventional unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

In the embodiment of the invention, the metal matrix-ceramic composite coating is prepared by adopting an atmospheric plasma spraying method, and the method specifically comprises the following steps:

s1, the iron-based amorphous alloy powder comprises the following raw materials in mass: ferroboron (B: 18%): 24% and ferrocolumbium (Nb: 65%): 13% of ferrosilicon (Si: 75%): 3% pure chromium: 17% and 43% pure iron, and the ceramic powder raw material contains 7 wt% ZrO₂Specifically, preparing iron-based amorphous alloy powder according to the content of the raw materials, and preparing YSZ powder by adopting a nitrogen atomization method and an agglomeration sintering method;

s2, mechanically mixing iron-based amorphous alloy powder and YSZ ceramic powder in proportion to obtain composite powder, then pretreating the surface of a metal matrix to remove an oxide film and dirt on the surface, and then performing sand blasting treatment on the metal matrix, wherein the mixing proportion is specifically that the volume ratio of the iron-based amorphous alloy powder to the YSZ ceramic powder is as follows: 4: 1;

s3, preparing the iron-based ceramic composite coating on the surface of the metal matrix by adopting an Atmospheric Plasma Spraying (APS) process for the composite powder prepared in the step S2, wherein the parameters of the spraying process are as follows: the current is 500-700A (preferably 600A), the argon flow is 30-50L/min (preferably 45L/min), the hydrogen flow is 6-8L/min (preferably 4L/min), the powder delivery rate is 42-60g/min, and the spraying distance is 110-140mm (preferably 135 mm).

By adopting the process, a batch of metal matrix-ceramic composite coatings are prepared under the same process conditions.