CN100522607C - Al2O3/Al-Si-Cr composite coatings and preparation method thereof - Google Patents

Abstract

The present invention discloses an Al2O3/Al-Si-Cr complex coating and the method for manufacturing the Al2O3/Al-Si-Cr complex coating on an Nb-24Ti-16Si-6Al-6Cr-2Hf matrix with the low-pressure 30-40 multiplied by 103pa plasma spraying process. The Al2O3/Al-Si-Cr complex coating consists of a Al2O3 coating and a Al-Si-Cr mixing coating; the Al2O3 coating is between the Al-Si-Cr mixing coating and the Nb-24Ti-16Si-6Al-6Cr-2Hf matrix; the thickness of the Al2O3 coating is 50 to 200Mu m and the thickness of the Al-Si-Cr mixing coating is 50 to 200Mu m; the Al-Si-Cr mixing coating of the Al2O3/Al-Si-Cr complex coating comprises Cr(Si,Al)2, Al, Si which can form continuous dense layer of mixed oxides of Al2O3 and SiO2 after 100 hours oxidation with the temperature of 1000 to 1250 Celsius degrees; the Al2O3 coating can effectively prevent the diffusion of Al-Si-Cr mixed coating and matrix which promotes the continuous anti-oxidation life of the coating.

Description

Al 2O 3/ Al-Si-Cr composite coating and preparation method thereof

Technical field

The present invention relates to a kind of preparation method of coating, more particularly, refer to a kind of employing low pressure (30～40 * 10 ³Pa) plasma spraying method is prepared the Al of (1000～1250 ℃) antioxygenic property that has high temperature at the Nb-24Ti-16Si-6Al-6Cr-2Hf matrix ₂O ₃/ Al-Si-Cr composite coating.

Background technology

Niobium-base alloy has 1700 ℃ of high melt point (〉), lower density (6.6～7.2g/cm ³), good room temperature fracture toughness (〉 20Mpam ^1/2), good high-temperature intensity and casting character, thereby be expected to become the blade material of under 1200～1400 ℃ even higher temperature, working.But Nb _Ss/ Nb ₅Si ₃The two-phase alloys antioxygenic property is poor, has serious oxidation weight gain phenomenon during high-temperature oxydation.The oxide that forms is as TiNb ₂O ₇, AlNb ₁₁O ₂₉And CrNbO ₄Etc. loose porous, and growth rapidly, can't stop the continuation diffusion of oxygen to matrix, thereby not reach the high-temperature oxidation resistant effect.

Al, Cr, three kinds of elements of Si have superior high-temperature oxidation resistant effect, their oxide Al ₂O ₃, SiO ₂And Cr ₂O ₃Can stop the diffusion of oxygen, stop further carrying out of oxidation.Al, Cr, Si form chemical compound lot through chemical combination, and these compounds all have good high-temperature oxidation resistance, but part of compounds is subjected to the influence of its fusing point, have limited its high temperature and have used.Cr (Al, Si) ₂Good in oxidation resistance, 1250 ℃ of fusing point height (〉).Thereby has a very high high temperature using value.

Al ₂O ₃Has very high fusing point, fine and close Al ₂O ₃Layer not only can stop the diffusion of oxygen element, and can stop Nb, Ti, Al, Cr, Si etc. than the diffusion of the element of thick atom radius, is the selection that well hinders diffusion layer material.

Along with the development of coating technology, more high-performance, the coating system of labyrinth is developed gradually more.The development multi-layer composite coatings is one of important directions of present coating development.In the high-temperature oxidation resistant coating system, ORC can lose efficacy gradually along with the increase of oxidization time.Causing its failure reasons mainly is the consumption of active element.The consumption of active element comprises two processes: the oxygen that (1) active element spreads in environment is combined and is formed oxide; (2) active element spreads to the matrix direction in hot environment.In order to improve the service life of coating, it is very necessary increasing one deck resistance diffusion layer between anti oxidation layer and matrix.

Summary of the invention

One of purpose of the present invention provides a kind of Al ₂O ₃/ Al-Si-Cr composite coating, this composite coating is by Al ₂O ₃Coating and Al-Si-Cr mixed layer form, Al ₂O ₃Coating between Al-Si-Cr mixed layer and Nb-24Ti-16Si-6Al-6Cr-2Hf matrix, Al ₂O ₃Coating layer thickness is 50～200 μ m, and Al-Si-Cr mixed layer thickness is 50～200 μ m.The Al-Si-Cr mixed layer is by Cr (Si, Al) ₂, Al, Si three phase compositions, it is formed with Al with interior on Al-Si-Cr mixed layer surface at 1000～1250 ℃ of oxidation 100h of high temperature ₂O ₃And SiO ₂Mixed oxide layer, can successfully stop oxygen to the diffusion of matrix.The Al that the present invention makes ₂O ₃The coating section of (during 1000～1250 ℃ of oxidation 100h of oxidizing condition) shows that coating forms by three layers after the oxidation after the oxidation of/Al-Si-Cr composite coating process sem analysis: skin is the oxide skin(coating) of Al-Si-Cr mixed coating; The intermediate layer is the Al-Si-Cr mixed coating; Internal layer is Al ₂O ₃Al ₂O ₃Layer has played the resistance diffusion in oxidizing process, successfully stoped the counterdiffusion effect between matrix and the coating.

Another object of the present invention is to propose a kind of employing low pressure 30～40 * 10 ³The pa plasma spraying prepares Al ₂O ₃The method of/Al-Si-Cr composite coating is at first prepared Al at the Nb-24Ti-16Si-6Al-6Cr-2Hf matrix ₂O ₃Coating is then at Al ₂O ₃Prepare the Al-Si-Cr mixed coating on the coating; Have Cr (Al, Si) in the Al-Si-Cr mixed coating ₂, the material such as Si and Al, when 1000～1250 ℃ of oxidation 100h of high temperature, can form continuous, fine and close Al ₂O ₃And SiO ₂Mixed oxide layer, thus the further oxidized of coatings and substrate stoped, improved the high temperature oxidation resistance of Nb-24Ti-16Si-6Al-6Cr-2Hf matrix; Simultaneously, described Al when 1000～1250 ℃ of oxidation 100h of high temperature ₂O ₃Coating can successfully stop the counterdiffusion between Al-Si-Cr mixed coating and the matrix, thereby has improved the lasting anti-oxidant life-span of coating.

Al of the present invention ₂O ₃/ Al-Si-Cr composite coating is by adopting the preparation of low-voltage plasma spraying technology on the Nb-24Ti-16Si-6Al-6Cr-2Hf matrix, and preparation has Al between matrix and Al-Si-Cr mixed coating ₂O ₃Coating; Al ₂O ₃/ Al-Si-Cr composite coating can form the Al of continuous densification when 1000～1250 ℃ of oxidations of high temperature ₂O ₃And SiO ₂Mixed oxide layer, thus the further oxidized of coatings and substrate stoped, improved the high temperature oxidation resistance of Nb-24Ti-16Si-6Al-6Cr-2Hf matrix, preparing cated matrix surface unit are weightening finish is 4.2～9.8mg/cm ²

Description of drawings

Fig. 1 makes Al at matrix ₂O ₃The section structure schematic diagram of/Al-Si-Cr composite coating.

Fig. 2 is the Al after the oxidation ₂O ₃The section structure schematic diagram of/Al-Si-Cr composite coating.

The specific embodiment

The present invention is described in further detail below in conjunction with drawings and Examples.

The present invention is a kind of high temperature resistance (1000～1250 ℃) oxidation Al ₂O ₃/ Al-Si-Cr composite coating, described Al ₂O ₃/ Al-Si-Cr composite coating is by Al ₂O ₃Coating and Al-Si-Cr mixed layer form, Al ₂O ₃Coating is between Al-Si-Cr mixed layer and Nb-24Ti-16Si-6Al-6Cr-2Hf matrix.Described Al ₂O ₃Coating layer thickness is 50～200 μ m.Described Al-Si-Cr mixed layer thickness is 50～200 μ m, and this coating is by Cr (Si, Al) ₂, Al, Si three phase compositions, Al-Si-Cr mixed layer surface is formed with Al when 1000～1250 ℃ of oxidation 100h of high temperature ₂O ₃And SiO ₂Mixed oxide layer.

The present invention is a kind of employing low pressure 30～40 * 10 ³The pa plasma spraying prepares Al ₂O ₃The method of/Al-Si-Cr composite coating, this coating production has the following step:

The first step: the pre-treatment of matrix

With Nb-24Ti-16Si-6Al-6Cr-2Hf matrix adopting 150#, 360#, the polishing of 500# silicon carbide paper, and it is back stand-by to adopt sand-blasting machine to carry out the surface sand-blasting processing, matrix surface roughness RZ=60 after the sandblast～80 μ m;

Second step: preparation Al-Si-Cr coating material

(A) take by weighing the Al powder of 30～35wt%, the Cr powder of 30～33wt%, the Si powder of 32～40wt%, and the content sum of above-mentioned each composition is 100%, mixes after grind that to make granularity behind 30～150min be 250～350 purposes, first mixed-powders;

(B) will mix with binding agent through first mixed-powder that (A) step makes after to make granularity after grinding 250～400min be 250～350 purposes, second mixed-powders;

The consumption of first mixed-powder and binding agent is a binding agent of putting into 1000～1500ml in first mixed-powder of 1000g;

Described binding agent is stirred in 80～100 ℃ by gum arabic and deionized water and makes, and the consumption of gum arabic and deionized water is to add O.5 in every 100ml deionized water～the 5g gum arabic;

(C) will make granularity through second mixed-powder that (B) step makes after the atomization drying granulation is 200～250 purpose coating materials;

Atomization drying adopts centrifugal atomizing method, it (is coating material that the shearing force that second mixed-powder injects atomizer and is atomized device immediately through constant flow pump is dispersed into a lot of fine drop, its particle diameter is 40～80 μ m), wherein the atomizer rotating speed is 8000～20000r/min, the atomizer inlet temperature is 220～230 ℃, and the atomizer outlet temperature is 130～150 ℃;

The 3rd step: preparation Al ₂O ₃Coating material

Choose the Al that granularity is 200～250 purpose purity 99.9% ₂O ₃Spheroidal powder material;

The 4th step: low-voltage plasma spraying system coating

(A) matrix after the first step is processed is installed on the anchor clamps of low-voltage plasma spraying equipment, and will be through the Al of the 3rd step preparation ₂O ₃Coating material is put into feed appliance, regulates spraying parameter Al processed ₂O ₃Coating;

Plasma spraying parameter: jar internal pressure 30～40 * 10 ³Pa, the primary air amount is 60～100L/h, and inferior throughput is 25～30L/h, and arc current is 560～600A, and arc voltage is 50～60V, the powder sending quantity of powder feeder is 24～25g/min;

(B) second step preparation Al-Si-Cr coating material is put into feed appliance, regulate spraying parameter system Al-Si-Cr coating;

Plasma spraying parameter: jar internal pressure 30～40 * 10 ³Pa, the primary air amount is 60～100L/h, and inferior throughput is 25～30L/h, and electric current is 560～600A, and voltage is 50～60V, the powder sending quantity of powder feeder is 20～22g/min.

Al with the said method preparation ₂O ₃/ Al-Si-Cr composite coating shows that through XRD, sem analysis the Al-Si-Cr mixed coating is by Cr (Si, Al) ₂, Al, Si three phase compositions, this coating is formed with Al with interior on Al-Si-Cr mixed layer surface at 1000～1250 ℃ of oxidation 100h of high temperature ₂O ₃And SiO ₂Mixed oxide layer.

Embodiment 1:

The first step: the pre-treatment of matrix

With Nb-24Ti-16Si-6Al-6Cr-2Hf matrix cut growth 13mm, wide 8mm, the rectangle sample of high 3mm, and after adopting 150#, 360#, the polishing of 500# silicon carbide paper, it is stand-by that the employing sand-blasting machine carries out surface sand-blasting processing back, matrix surface roughness RZ=60 after the sandblast～80 μ m;

Second step: preparation coating material

(A) the Si powder that takes by weighing Cr powder, the 34.6wt% of Al powder, the 32.1wt% of 33.3wt% mixes after grind that to make granularity behind the 100min be 250～350 purposes, first mixed-powders;

(B) will mix with binding agent through first mixed-powder that (A) step makes after to make granularity after grinding 300min be 250～350 purposes, second mixed-powders;

The consumption of first mixed-powder and binding agent is a binding agent of putting into 1000ml in first mixed-powder of 1000g;

Described binding agent is stirred in 100 ℃ by gum arabic and deionized water and makes, and the consumption of gum arabic and deionized water is to add the 1g gum arabic in every 100ml deionized water;

(C) will make granularity through second mixed-powder that (B) step makes after the atomization drying granulation is 200～250 purpose coating materials;

Atomization drying adopts centrifugal atomizing method, second mixed-powder is dispersed into a lot of fine drop (particle diameter is 60～80 μ m) through the shearing force that constant flow pump injection atomizer also is atomized device immediately, wherein the atomizer rotating speed is 15000r/min, 225 ℃ of atomizer inlet temperatures, atomizer outlet temperature are 140 ℃.

The 3rd step: preparation Al ₂O ₃Coating material

Choose the Al that granularity is 200～250 purpose purity 99.9% ₂O ₃Spheroidal powder material;

The 4th step: low-voltage plasma spraying system coating

(A) matrix after the first step is processed is installed on the anchor clamps of low-voltage plasma spraying equipment, and will be through the Al of the 3rd step preparation ₂O ₃Coating material is put into feed appliance, regulates spraying parameter Al processed ₂O ₃Coating;

Plasma spraying parameter: jar internal pressure 30 * 10 ³Pa, the primary air amount is 60L/h, and inferior throughput is 25L/h, and electric current is 580A, and voltage is 55V, the powder sending quantity of powder feeder is 24g/min;

(B) second step preparation Al-Si-Cr coating material is put into feed appliance, regulate spraying parameter system Al-Si-Cr coating;

Plasma spraying parameter: jar internal pressure 30 * 10 ³Pa, the primary air amount is 60L/h, and inferior throughput is 25L/h, and electric current is 580A, and voltage is 55V, the powder sending quantity of powder feeder is 21g/min.

With the above-mentioned Al that makes ₂O ₃/ Al-Si-Cr composite coating shows through sem analysis, the Al of preparation ₂O ₃/ Al-Si-Cr composite coating mainly is made up of two-layer: outer is the Al-Si-Cr mixed layer, and this mixed layer is by Cr (Si, Al) ₂, Al, Si three phase compositions; Internal layer is the Al between coating and the matrix ₂O ₃Coating, its section structure signal as shown in Figure 1.

In air atmosphere, during through 1250 ℃ of isothermal oxidation 100h, the weightening finish of matrix surface unit are is 213mg/cm with the Nb-24Ti-16Si-6Al-6Cr-2Hf matrix ²

To make Al ₂O ₃The matrix of/Al-Si-Cr composite coating is in air atmosphere, and during through 1250 ℃ of isothermal oxidation 100h, the weightening finish of coating surface unit are is 9.8mg/cm ²Find (section structure is illustrated as shown in Figure 2) by the sem analysis to the oxidised samples section, coating mainly forms by three layers after the oxidation: skin is Al ₂O ₃And SiO ₂Mixed oxide layer; The intermediate layer is the Al-Si-Cr mixed layer; Internal layer is Al ₂O ₃Coating (100 μ m are arranged approximately).Coating surface after the oxidation shows that through XRD, sem analysis coating surface has formed continuous, fine and close Al ₂O ₃And SiO ₂Mixed oxide layer, thus the diffusion of oxygen to matrix successfully stoped.

By not comparing with preparing coating of material preparing cated matrix, its unit are weightening finish has reduced about 200mg/cm ², prove that the cated matrix of preparation has good high-temperature oxidation resistant effect.

Embodiment 2:

The first step: the pre-treatment of matrix

With Nb-24Ti-16Si-6Al-6Cr-2Hf matrix cut growth 13mm, wide 8mm, the rectangle sample of high 3mm, and after adopting 150#, 360#, the polishing of 500# silicon carbide paper, it is stand-by that the employing sand-blasting machine carries out surface sand-blasting processing back, matrix surface roughness RZ=60 after the sandblast～80 μ m;

Second step: preparation coating material

(A) the Si powder that takes by weighing Cr powder, the 40wt% of Al powder, the 30wt% of 30wt% mixes after grind that to make granularity behind the 150min be 250～350 purposes, first mixed-powders;

(B) will mix with binding agent through first mixed-powder that (A) step makes after to make granularity after grinding 400min be 250～350 purposes, second mixed-powders;

The consumption of first mixed-powder and binding agent is a binding agent of putting into 1500ml in first mixed-powder of 1000g;

Described binding agent is stirred in 80 ℃ by gum arabic and deionized water and makes, and the consumption of gum arabic and deionized water is to add the 5g gum arabic in every 100ml deionized water;

(C) will make granularity through second mixed-powder that (B) step makes after the atomization drying granulation is 200～250 purpose coating materials;

Atomization drying adopts centrifugal atomizing method, second mixed-powder is dispersed into a lot of fine drop (particle diameter is 40～70 μ m) through the shearing force that constant flow pump injection atomizer also is atomized device immediately, wherein the atomizer rotating speed is 20000r/min, the atomizer inlet temperature is 230 ℃, and the atomizer outlet temperature is 150 ℃.

The 3rd step: preparation Al ₂O ₃Coating material

Choose the Al that granularity is 200～250 purpose purity 99.9% ₂O ₃Spheroidal powder material;

The 4th step: low-voltage plasma spraying system coating

(A) matrix after the first step is processed is installed on the anchor clamps of low-voltage plasma spraying equipment, and will be through the Al of the 3rd step preparation ₂O ₃Coating material put into feed appliance, regulate spraying parameter Al processed ₂O ₃Coating;

Plasma spraying parameter: jar internal pressure 40 * 10 ³Pa, the primary air amount is 100L/h, and inferior throughput is 30L/h, and electric current is 600A, and voltage is 60V, the powder sending quantity of powder feeder is 25g/min;

(B) second step preparation Al-Si-Cr coating material is put into feed appliance, regulate spraying parameter system Al-Si-Cr mixed coating;

Plasma spraying parameter: jar internal pressure 40 * 10 ³Pa, the primary air amount is 100L/h, and inferior throughput is 30L/h, and electric current is 600A, and voltage is 60V, the powder sending quantity of powder feeder is 22g/min.

With the above-mentioned Al that makes ₂O ₃/ Al-Si-Cr composite coating shows that through sem analysis the coating of preparation mainly is made up of two-layer: outer is the Al-Si-Cr mixed layer, Cr (Si, Al) in this mixed layer ₂, Al, Si three phase compositions; Internal layer is the Al between coating and the matrix ₂O ₃Coating.

In air atmosphere, during through 1000 ℃ of isothermal oxidation 100h, the weightening finish of matrix surface unit are is 44.6mg/cm with the Nb-24Ti-16Si-6Al-6Cr-2Hf matrix ²

In air atmosphere, during through 1000 ℃ of isothermal oxidation 100h, the weightening finish of coating surface unit are is 4.2mg/cm with the matrix that makes the Al-Si-Cr coating ²Find that by the sem analysis to the oxidised samples section coating mainly forms by three layers after the oxidation: skin is Al ₂O ₃And SiO ₂Mixed oxide layer; The intermediate layer is the Al-Si-Cr mixed layer; Internal layer is Al ₂O ₃Layer (200 μ m are arranged approximately).Coating surface after the oxidation shows that through XRD, sem analysis coating surface has formed continuous, fine and close Al ₂O ₃And SiO ₂Mixed oxide layer, thus the diffusion of oxygen to matrix successfully stoped.

By not comparing with preparing coating of material preparing cated matrix, its unit are weightening finish has reduced about 40mg/cm ², prove that the cated matrix of preparation has good high-temperature oxidation resistant effect.

Claims (4)

1, a kind of Al ₂O ₃/ Al-Si-Cr composite coating, described Al ₂O ₃The preparation of/Al-Si-Cr composite coating is characterized in that: described Al on the Nb-24Ti-16Si-6Al-6Cr-2Hf matrix ₂O ₃/ Al-Si-Cr composite coating is by Al ₂O ₃Coating and Al-Si-Cr mixed layer form, Al ₂O ₃Coating between Al-Si-Cr mixed layer and Nb-24Ti-16Si-6Al-6Cr-2Hf matrix, Al ₂O ₃Coating layer thickness is 50～200 μ m, and Al-Si-Cr mixed layer thickness is 50～200 μ m.

2, Al according to claim 1 ₂O ₃/ Al-Si-Cr composite coating is characterized in that: the Al-Si-Cr mixed coating is formed with Al with interior on Al-Si-Cr mixed layer surface at 1000～1250 ℃ of oxidation 100h of high temperature ₂O ₃And SiO ₂Mixed oxide layer.

3, Al according to claim 1 ₂O ₃/ Al-Si-Cr composite coating is characterized in that: preparation has Al ₂O ₃The matrix of/Al-Si-Cr composite coating is when 1000～1250 ℃ of high-temperature oxydation 100h, and the unit are weightening finish is 4.2～9.8mg/cm ²

4, a kind of employing low pressure 30～40 * 10 ³The pa plasma spraying prepares Al ₂O ₃The method of/Al-Si-Cr composite coating is characterized in that following preparation steps is arranged:

The first step: the pre-treatment of matrix

With Nb-24Ti-16Si-6Al-6Cr-2Hf matrix adopting 150#, 360#, the polishing of 500# silicon carbide paper, and it is back stand-by to adopt sand-blasting machine to carry out the surface sand-blasting processing, matrix surface roughness RZ=60 after the sandblast～80 μ m;

Second step: preparation Al-Si-Cr coating material

(A) take by weighing the Al powder of 30～35wt%, the Cr powder of 30～33wt%, the Si powder of 32～40wt%, and the content sum of above-mentioned each composition is 100%, mixes after grind that to make granularity behind 30～150mm be 250～350 purposes, first mixed-powders;

(B) will mix with binding agent through first mixed-powder that (A) step makes after to make granularity after grinding 250～400min be 250～350 purposes, second mixed-powders;

The consumption of first mixed-powder and binding agent is a binding agent of putting into 1000～1500ml in first mixed-powder of 1000g;

Described binding agent is stirred in 80～100 ℃ by gum arabic and deionized water and makes, and the consumption of gum arabic and deionized water is to add 0.5～5g gum arabic in every 100ml deionized water;

(C) will make granularity through second mixed-powder that (B) step makes after the atomization drying granulation is 200～250 purpose coating materials;

Atomization drying adopts centrifugal atomizing method, second mixed-powder is dispersed into a lot of fine drop through the shearing force that constant flow pump injection atomizer also is atomized device immediately, wherein the atomizer rotating speed is 8000～20000r/min, the atomizer inlet temperature is 220～230 ℃, and the atomizer outlet temperature is 130～150 ℃;

The 3rd step: preparation Al ₂O ₃Coating material

Choosing granularity is 200～250 purpose Al ₂O ₃Powder;

The 4th step: low-voltage plasma spraying system coating

(A) matrix after the first step is processed is installed on the anchor clamps of low-voltage plasma spraying equipment, and will be through the Al of the 3rd step preparation ₂O ₃Coating material is put into feed appliance, regulates spraying parameter Al processed ₂O ₃Coating;

Plasma spraying parameter: jar internal pressure 30～40 * 10 ³Pa, the primary air amount is 60～100L/h, and inferior throughput is 25～30L/h, and electric current is 560～600A, and voltage is 50～60V, the powder sending quantity of powder feeder is 24～25g/min;

(B) second step preparation Al-Si-Cr mixed coating material is put into feed appliance, regulate spraying parameter system Al-Si-Cr mixed coating;

Plasma spraying parameter: jar internal pressure 30～40 * 10 ³Pa, the primary air amount is 60～100L/h, and inferior throughput is 25～30L/h, and electric current is 560～600A, and voltage is 50～60V, the powder sending quantity of powder feeder is 20～22g/min.

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