钼添加对CrN涂层抗氧化性能的影响

Influence of Molybdenum Addition on Oxidation Resistance of CrN Coatings

摘要:

研究钼添加对CrN涂层微观结构和抗氧化性能的影响，采用反应磁控溅射法在硅片和高速钢片上制备不同Mo含量的Cr-Mo-N涂层，并在500~800 ℃的高温空气中退火1 h，用X射线衍射（XRD）、拉曼光谱和扫描电子显微镜（SEM）对涂层退火前后的微观形貌进行表征。沉积的CrN和Cr-Mo-N涂层均表现出基于CrN晶格的B1面心立方相（fcc）。Mo离子取代Cr-N晶格中的Cr离子，形成Cr-Mo-N固溶体。在600 ℃时，XRD和拉曼光谱表明，Mo含量较高的Cr-Mo-N涂层中形成MoO₃相，表面较粗糙，含氧量较高。在700 ℃时，CrN涂层由于内应力的作用，其横截面形貌为疏松的柱状晶，并有一定的多孔区，而Cr-Mo-N涂层则为致密的柱状晶结构。低Mo含量（<17at%）的Cr-Mo-N涂层比CrN涂层具有更好的抗氧化性。

Abstract:

To investigate the effect of molybdenum (Mo) addition on microstructure and oxidation resistance of CrN coating, Cr-Mo-N coatings with different Mo contents were fabricated on silicon wafers and high speed steel by reactive magnetron sputtering and annealed at elevated temperatures from 500 °C to 800 °C in air for 1 h. The coatings before and after annealing were characterized by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscope (SEM). The results show that the as-deposited CrN and Cr-Mo-N coatings all exhibit B1 face-centered cubic (fcc) phase based on the CrN lattice. Mo ions substitute for Cr ions in Cr-N lattice, forming the solid solution Cr-Mo-N coatings. At 600 °C, XRD and Raman spectra show that the MoO₃ phase forms in Cr-Mo-N coatings with higher Mo contents, indicating a coarser surface with higher oxygen content. At 700 °C, the cross sectional morphology of the CrN coating exhibits loose columnar grains with some porous regions due to the internal stress while the Cr-Mo-N coating shows the dense columnar structure. This study reveals that the Cr-Mo-N coatings with lower Mo contents (<17at%) have better oxidation resistance than the CrN coating does.