(1. 安徽工業(yè)大學(xué) 先進(jìn)金屬材料綠色制備與表面技術(shù)教育部重點(diǎn)實(shí)驗(yàn)室，馬鞍山 243002；
2. 安徽工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，馬鞍山 243002；
3. 安徽馬鋼表面技術(shù)股份有限公司，馬鞍山 243000；
4. 中國(guó)航天材料與工藝研究所，北京 100076；
5. 馬鋼(集團(tuán))控股有限公司，馬鞍山 243000)
摘 要: 采用超音速火焰噴涂(HVOF)技術(shù)制備氧燃比分別為3.91、4.31、4.62、5.39的NiCrAlY涂層，利用XRD、SEM、EDS、顯微硬度計(jì)、拉伸試驗(yàn)機(jī)分析表征涂層微觀組織結(jié)構(gòu)及力學(xué)性能的變化規(guī)律，進(jìn)而研究微觀組織結(jié)構(gòu)的變化對(duì)涂層在KCl熔鹽環(huán)境中熱腐蝕性能的影響。結(jié)果表明：隨著氧燃比的升高，涂層中γ/γ′峰向高角度偏移，涂層結(jié)構(gòu)變得致密，未熔化粒子邊界減少，涂層結(jié)合強(qiáng)度由49 MPa提高到62 MPa，涂層顯微硬度變化較小。涂層平均熱腐蝕質(zhì)量增加速率常數(shù)Kp由93.37 mg2/(cm4·h)降低到1.54 mg2/(cm4·h)，說(shuō)明涂層抗熱腐蝕性能隨著氧燃比的增大而升高。這主要是由于高氧燃比涂層中較少的孔隙及未熔化粒子邊界，使得Cl、O向內(nèi)擴(kuò)散通道減少，涂層氯化-氧化程度降低，從而賦予涂層更優(yōu)異的抗熱腐蝕性能。
關(guān)鍵字: 超音速火焰噴涂；NiCrAlY涂層；氧燃比；微觀結(jié)構(gòu)；熱腐蝕
（1. Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials, Ministry of Education, Anhui University of Technology, Ma’anshan 243002, China;
2. School of Materials Science and Engineering, Anhui University of Technology, Ma’anshan 243002, China;
3. Anhui Masteel Surface Technology Co., Ltd., Ma’anshan 243000, China;
4. China Aerospace Materials and Technology Research Institute, Beijing 100076, China;
5. Masteel (Group) Holding Company Ltd., Ma’anshan 243000, China）
Abstract:The NiCrAlY coatings with oxygen-fuel ratio of 3.91, 4.31, 4.62 and 5.39, respectively, were prepared by high-velocity oxygen fuel spraying (HVOF). The changes of microstructure and mechanical properties of the coating were characterized by XRD, SEM, EDS, microhardness meter and tensile testing machine. Then, the effect of microstructure on hot corrosion behaviors of coatings in KCl molten salt environment was investigated. The results show that, with the increase of the oxygen-fuel ratio, the γ/γ′ peak shifts to a high angle, the denser coating structure is obtained and the boundaries of unmelted particles decrease. The coating bonding strength increases from 49 MPa to 62 MPa, while the oxygen-fuel ratio has little effect on the microhardness of the coating. The average hot corrosion rate constant Kp decreases from 93.37 mg2/(cm4·h) to 1.54 mg2/(cm4·h), which implies that the hot corrosion resistance of the coating enhances with the increase of oxygen-fuel ratio. The lower porosity and fewer unmelted particle boundaries in the high oxygen-fuel ratio coating result in the decrease of the diffusion channels of Cl and O. So, the extent of chlorination-oxidation of the coating decreases, thereby, endowing the coating with better hot corrosion resistance.
Key words: high-velocity oxygen fuel spraying; NiCrAlY coating; oxygen-fuel ratio; microstructure; hot corrosion
