Sun Yijiao, Li Hongxiang, Yang Jun, Zhang Jishan
State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China.
National Engineering Laboratory for Exploration and Development of Low-Permeability Oil & Gas Fields, Xi'an 710021, China.
Materials (Basel). 2023 Feb 3;16(3):1313. doi: 10.3390/ma16031313.
To retard the degradation of the magnesium alloys for dissolvable ball seats, Fe-based amorphous coatings were deposited on dissolvable Mg-RE alloy substrates using high velocity oxygen-fuel spraying technology. The results show that the Fe-based amorphous coatings possess low porosity (0.82%) and high amorphous contents (91.4%) and their corrosion resistance decreases with the increase of temperature or pressure. However, with the help of Fe-based amorphous coatings, the degradation time of dissolvable Mg-RE alloy has been significantly prolonged. In particular, the service life of coated Mg-RE alloy exceeds 360 h at temperatures below 50 °C and reaches 87 h at 120 °C and 80 atm. Under high temperature and high pressure, the compactness of passive films decreases and the chemical activities of ions and metal elements increase, leading to the degradation of corrosion resistance of Fe-based amorphous coatings. In long-term corrosion, the crystallized splats are prone to corrosion because of the multiphase structures. The corroded crystallized splats are connected to the inevitable pores by the corroded intersplat regions, resulting in the formation of corrosion channels and the corrosion failure of coatings. This study provides a useful guidance for the corrosion protection of dissolvable plugging tools made of magnesium alloys.
为延缓可溶球座镁合金的降解，采用高速氧燃料喷涂技术在可溶Mg-RE合金基体上沉积铁基非晶涂层。结果表明，铁基非晶涂层孔隙率低（0.82%）、非晶含量高（91.4%），其耐蚀性随温度或压力的升高而降低。然而，在铁基非晶涂层的帮助下，可溶Mg-RE合金的降解时间显著延长。特别是，涂层Mg-RE合金在50℃以下温度下的使用寿命超过360小时，在120℃和80个大气压下达到87小时。在高温高压下，钝化膜的致密性降低，离子和金属元素的化学活性增加，导致铁基非晶涂层耐蚀性下降。在长期腐蚀过程中，由于多相结构，结晶薄片易于腐蚀。被腐蚀的结晶薄片通过被腐蚀的薄片间区域与不可避免的孔隙相连，导致腐蚀通道的形成和涂层的腐蚀失效。该研究为镁合金制成的可溶封堵工具的腐蚀防护提供了有益的指导。
