纳米NiCrBSi-TiB_2涂层在Na_2SO_4-60%V_2O_5熔盐中的热腐蚀行为  

Hot Corrosion Behavior of Nanocrystalline NiCrBSi-TiB_2 Coating in Na_2SO_4-60% V_2O_5 Molten Salt

作　　者：吴姚莎[1] 

机构地区：[1]中山火炬职业技术学院光电工程系,广东中山528436

出　　处：《热加工工艺》2015年第18期123-126,共4页Hot Working Technology

基　　金：广东省自然科学基金资助项目(S201304001636);中山市科技计划项目(20123A380)

摘　　要：采用超音速火焰喷涂技术在碳钢表面制备了纳米和微米NiCrBSi-TiB2涂层,并研究了两涂层在800℃下的Na2SO4-60%V2O5熔盐热腐蚀行为。结果表明:纳米涂层具有更好的抗熔盐热腐蚀性能,其在Na2SO4-V2O5熔盐作用下的热腐蚀机理为酸性熔融机制。晶粒纳米化能够提高扩散系数和降低内应力,使得涂层在腐蚀初期能快速地形成一层膜基结合强度高的SiO2膜。SiO2在酸性熔盐中的溶解度低,能够有效地将熔盐和涂层分离,降低了熔盐对涂层的侵蚀作用,对涂层起到保护作用。The nanocrystalline and conventional NiCrBSi-TiB2 coatings were sprayed by high velocity oxy-fuel （HVOF）. Hot corrosion behavior in Na2SO4-60%V2O5 molten salt at 800 ℃ was investigated for both NiCrBSi-TiB2 coatings by TG, SEM/EDS and XRD. The results indicate that the nanocrystalline coating exhibits better hot corrosion resistance than that of the conventional coating, and its hot corrosion is controlled by a acidic fluxing mechanism. The reasons for the better hot corrosion resistance of the nanocrystalline coating can be attribute to the fact that the faster diffusion coefficient of Si and lower inter stress attributed to the nano-crystalline can be formation a intact protective SiO2 film, because of the low solubility of SiO2 in Na2SO4-V2O5 molten salt. which can effectively senarates and oroteetes the eoating from molten salt.

关 键 词：纳米 Ni Cr BSi-Ti B2涂层 Na2SO4-V2O5 热腐蚀 超音速火焰喷涂 

分 类 号：TG174.442[金属学及工艺—金属表面处理]