A method of life prediction for environmental barrier coating EBC

A technology of life prediction and coating, applied in measuring devices, instruments, scientific instruments, etc., can solve the problems of long time consumption, high cost of testing equipment and environmental assessment tests, and achieve the effects of low cost, simple and reliable method, and short time.

Inactive Publication Date: 2016-02-24
NORTHWESTERN POLYTECHNICAL UNIV
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

Using the simulation test of all environmental factors (that is, assessing the EBC coating in a real gas environment) can obtain the life of the EBC coating, but it takes a long time to use the simulation test of all environmental factors, and the test equipment and environmental assessment test are limited. The cost is also high, and similar trials are usually only carried out in the industrial sector

Method used

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  • A method of life prediction for environmental barrier coating EBC
  • A method of life prediction for environmental barrier coating EBC
  • A method of life prediction for environmental barrier coating EBC

Examples

Experimental program
Comparison scheme
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specific Embodiment 1

[0036] Specific embodiment 1: the lifetime prediction of BSAS-EBC coating

[0037] Concrete preparation steps are as follows:

[0038] 1. Preparation of silicon carbide bonding layer:

[0039] Selection of continuous carbon fiber reinforced silicon carbide ceramic matrix composites (C f / SiC), the C f / SiC is made into a strip sample with a size of 40×5×3.5mm, which is cleaned by ultrasonic waves. A dense silicon carbide bonding layer was prepared on the surface of the sample by chemical vapor deposition (CVD). Using a scanning electron microscope (SEM), measure the thickness of the bondline, as figure 1 shown. In this embodiment, the adhesive layer has a thickness of 30 μm.

[0040] 2. Preparation of BSAS-EBC coating:

[0041] 1) Add 20wt% of the total weight of polyazide silane to 80% of the total weight of alcohol to prepare a polyazide silane solution, add 45 wt% of the BSAS powder to the polyazide silane solution, and then add the total 5 wt% H 3 BO 3 As a sinte...

Embodiment 2

[0055] Embodiment 2: adopt slurry method to prepare Sc 2 Si 2 o 7 The EBC coating, its preparation process and performance assessment method are the same as in Example 1. In this example, C f / SiC uses silicon carbide (thickness 30μm) as the bonding layer, and its SiO 2 The critical thickness of the layer is 5.5 μm; at the same time, the Sc 2 Si 2 o 7 The coating thickness is 50 μm, the oxidation and corrosion kinetic constant k corresponding to the coating p The value is: k p =0.0541, using the formula (3) to predict the life of this coating in the water and oxygen corrosion environment is 559h. A long-term water-oxygen corrosion assessment was carried out on the sample. After 550 hours of water-oxygen corrosion, the coating failed, which shows that in the water-oxygen corrosion environment, the Sc 2 Si 2 o 7 The whole life of the coating is about 550h. This is very close to the predicted life, indicating that the prediction method is feasible.

Embodiment 3

[0056] Embodiment 3: adopt slurry method to prepare BSAS-Sc 2 Si 2 o 7 The EBC coating, its preparation process and performance assessment method are the same as in Example 1. In this example, C f / SiC uses silicon carbide (thickness 30μm) as the bonding layer, and its SiO 2 The critical thickness of the layer is 5.5 μm; meanwhile, BSAS-Sc 2 Si 2 o 7 The coating thickness is 50 μm, the oxidation and corrosion kinetic constant k corresponding to the coating p The value is: k p =0.0653, using the formula (3) to predict the life of this coating in the water-oxygen corrosion environment is about 463h. A long-term water-oxygen corrosion assessment was carried out on the sample. After 450 hours of water-oxygen corrosion, the coating failed, which shows that the BSAS-Sc in the water-oxygen corrosion environment 2 Si 2 o 7 The whole life of the coating is about 450h. This is very close to the predicted life, indicating that the prediction method is feasible.

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Abstract

The invention relates to a method for predicting the service life of environmental barrier coatings (EBC), and belongs to the field of monitoring of coatings. The method comprises the steps: obtaining an oxidization corrosion kinetic constant through the change of the thickness of a SiO2 layer within limited oxidation corrosion testing time, and predicating the service life of the EBC by using the critical thickness of the SiO2 layer as the basis of failure of the EBC and combining with an oxidation corrosion kinetic equation. The method provided by the invention is relatively low in cost, can be suitable for a continuous carbon fiber toughened silicon carbide ceramic matrix composite (Cf / SiC), also can be suitable for a continuous silicon carbide fiber toughened silicon carbide ceramic matrix composite (SiCf / SiC), and simultaneously can be suitable for multiple EBC systems; due to universality of a using environment, the method can be suitable for a control factor simulation test, and can also be suitable for a all-computer factor simulation test; the method has the guiding significance to the selection of an EBC material and the optimized design of the EBC; the method is simple and reliable.

Description

technical field [0001] The invention belongs to the field of coating monitoring, and in particular relates to a method for predicting the service life of environmental barrier coatings (Environmental barrier coatings, EBC). Background technique [0002] Continuous fiber toughened silicon carbide ceramic matrix composites (CMC-SiC, including SiC f / SiC and C f / SiC) has the characteristics of high specific strength, high specific modulus, oxidation resistance and low density, and has become an ideal candidate material for aero-engine hot-end parts. In air or dry oxygen environment, a layer of dense SiO will form on the surface of CMC-SiC 2 protective film due to SiO 2 It has low oxygen partial pressure and oxygen diffusion coefficient at high temperature, therefore, CMC-SiC has very good oxidation resistance in air or dry oxygen environment. However, in the engine combustion chamber environment, the SiO formed on the surface of CMC-SiC 2 The protective film will be erod...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N17/00
Inventor 王一光陆永洪成来飞张立同
Owner NORTHWESTERN POLYTECHNICAL UNIV
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