喷涂功率对YSZ涂层的力学性能和抗铝硅熔体腐蚀性能的影响

热浸镀Al–Si合金涂层是一种有效的现代钢铁防腐涂层，但熔融Al–Si合金腐蚀已成为热浸镀Al–Si合金生产线沉没辊及其备件亟待解决的关键问题之一。本工作采用大气等离子喷涂技术制备Y2O3部分稳定ZrO2(YSZ)/NiCrAlY防护涂层，研究了喷涂功率对YSZ涂层组织和力学性能的影响和涂层在700℃下Al–Si熔体中的腐蚀行为。结果表明，YSZ涂层是由板条和层间柱状晶粒组成的典型层状结构，随着喷涂功率从37 kW增至46 kW，层间柱状结晶呈长大趋势；YSZ涂层主要由t-ZrO2相和少量m-ZrO2相组成，喷涂功率对涂层相组成无明显影响；喷涂功率为40 kW的YSZ涂层具有较高的显微硬度642.4 HV0.3和结合强度62 MPa。此外，当带有涂层的样品在700℃的Al–Si熔液中腐蚀240 h后，YSZ涂层与高温Al–Si熔液之间的界面没有反应层生成，同时Al–Si合金熔液中的Al和Si元素也未渗透进YSZ涂层内部，表明YSZ/NiCrAlY防护涂层有效地将Al–Si合金熔体阻挡在涂层表面。

Influence of spraying power on mechanical and resistance to aluminum-silicon melt corrosion properties of YSZ coating

Hot-dip Al–Si alloy coating is an effective corrosion resistant coating for modern steel. However, the molten Al–Si alloy corrosion has become one of the problems to be urgently solved for sink rollers and their spare parts in the hot-dip Al–Si alloy production line. In this work, yttria partially stabilized zirconia (YSZ)/NiCrAlY protective coating was fabricated by air plasma spraying. The influence of spraying power on the microstructure and mechanical properties of the YSZ coating, and its corrosion behavior in Al–Si melt at 700℃ was also investigated. The results showed that YSZ coating presented a typical layered structure with lath-shaped and interlayer columnar grains. The interlayer columnar grains tended to grow up with the increase of spraying power from 37 kW to 46 kW. YSZ coating was mainly composed of t-ZrO2 phase and small amount of m-ZrO2 phase, and spraying power had no obvious influence on the phase compositions. The YSZ coating with 40 kW spraying power had relatively high microhardness and adherence strength values (642.4 HV0.3 and 62 MPa). Additionally, no reaction layer was formed at the interface between YSZ coating and Al–Si melt at 700℃ for 240 h, and the Si and Al elements in the molten Al–Si alloy also did not infiltrate into the YSZ coating, suggesting that YSZ/NiCrAlY protective coating could effectively prevent Al–Si alloy melt on the surface of coating.