文章信息/Info

Title:

Evaluation Methodology of Oxidation Resistance of Porous Abradable Coating

文章編號:

1674-3962(2024)09-0832-07

作者:

孫澤睿; 董琳; 劉梅軍; 楊冠軍

西安交通大學(xué)材料科學(xué)與工程學(xué)院 金屬材料強(qiáng)度國家重點實驗室，陜西 西安 710049

Author(s):

SUN Zerui;  DONG Lin;  LIU Meijun;  YANG Guanjun

State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering,Xi‘a(chǎn)n Jiaotong University, Xi’an 710049, China

關(guān)鍵詞:

封嚴(yán)涂層; 孔隙; 接觸面積; 氧化動力學(xué); 抗氧化性

Keywords:

sealing coating;  pore;  contact area;  oxidation kinetics;  oxidation resistance

分類號:

TG174.4

DOI:

10.7502/j.issn.1674-3962.202209038

文獻(xiàn)標(biāo)志碼:

A

摘要:

防鈦火可磨耗封嚴(yán)涂層的抗氧化性能是決定其服役壽命的重要因素。然而，當(dāng)涂層呈現(xiàn)孔隙率高達(dá)50%量級的多孔結(jié)構(gòu)，經(jīng)典的氧化增重評價方法不適用。為構(gòu)建多孔結(jié)構(gòu)涂層抗氧化性能的合理評價方法，以防鈦火可磨耗封嚴(yán)涂層為典型的多孔結(jié)構(gòu)合金涂層研究對象，通過系統(tǒng)研究涂層氧化動力學(xué)規(guī)律、氧化膜分布特征，揭示了多孔結(jié)構(gòu)涂層內(nèi)表面氧化機(jī)制，建立合理考慮涂層實際氧化表面積的多孔結(jié)構(gòu)涂層抗氧化性能評價方法。結(jié)果表明，孔隙作為環(huán)境氧的快速擴(kuò)散通道，使涂層與環(huán)境氧的接觸面積增大2個數(shù)量級，導(dǎo)致根據(jù)經(jīng)典氧化增重法所得氧化膜厚度比實際表面氧化膜厚度高2個數(shù)量級。據(jù)此，通過建模計算包含外表面和內(nèi)表面的多孔涂層實際氧化面積，構(gòu)建基于實際氧化表面積的涂層抗氧化評價方法。采用該方法評價NiCrAl�才驖櫷量赡ズ姆鈬�(yán)涂層，得出600 ℃空氣氧化條件下該涂層平均氧化速率為1��8×10-2 g·m-2·h-1，達(dá)到標(biāo)準(zhǔn)HB5258—2000規(guī)定的完全抗氧化級。上述評價方法為準(zhǔn)確評價多孔涂層抗氧化性能從而保障涂層可靠服役提供方法支撐。

Abstract:

Oxidation resistance of the abradable sealing coating is an important factor in determining its service life. However, the sealing coating possesses a porous structure with porosity up to 50%, which makes classical weight gain rate evaluation methods inapplicable. To evaluate the oxidation resistance of porous coating accurately, this work investigated the typical porous abradable sealing coating. First, oxidation kinetics of the coating and distribution of oxide film were systematically studied. Then, an inner surface oxidation mechanism of the porous coating was revealed. Finally, a reasonable method for evaluating the oxidation resistance of porous coating considering the actual oxidized surface area was established. Results showed that pores in the coating served as rapid diffusion channels for oxygen in the environment, significantly increasing in the contact area between the coating and the environment by several orders of magnitude, and an increase in the calculated oxide film thickness by several orders of magnitude than the actual oxide film thickness. Based on this, this work calculated the actual oxidation area by establishing a porous coating model and thus established an evaluation method of the oxidation resistance. According to the proposed evaluation method, the average oxidation rate at 600 ℃ under air condition of NiCrAl�瞓entonite abradable sealing coating prepared in this work was 1.8×10-2 g·m-2·h-1, which had reached the level of complete oxidation resistance based on standard HB5258—2000. The established evaluation method is meaningful for accurately evaluating the oxidation resistance performance of porous coatings to ensure their reliable service.