Abstract: In response to the carbon-free requirements of ladle refractories,a coating slurry was prepared using calcined α-Al₂O₃ powder and yttrium-stabilized zirconia as coating fillers and silane coupling agent (KH-560) as a dispersant,with the addition of a magnesia-aluminia binder.The slurry was brushed onto the surface of a corundum-magnesium aluminate spinel substrate with sizes of 40 mm×40 mm×10 mm,and the coated sample was obtained after the heat treatment at 1 600 ℃ for 1 h.The effects of the KH-560 additions (0,0.5%,1%,1.5%,2%,2.5%,and 3% of the coating filler mass) on the slurry properties and the corrosion resistance of the coating were investigated.The results show that:(1)at room temperature,KH-560 dehydrates and condenses with the hydroxylated Al₂O₃ surface to form a uniform adsorption layer,whose steric hindrance effect reduces the surface tension and viscosity of the slurry,significantly improving its stability;(2)after the heat treatment at 1 600 ℃,mullite is generated by the chemical bonding of KH-560 and Al₂O₃,strengthening the bonding strength between the coating and the substrate;(3)the slag corrosion resistance test shows that,compared with the coated sample without KH-560,the aggregate edges at the corrosion interface of the sample with 1% KH-560 remain intact,the matrix shows no liquid-phase infiltration,and the corrosion index is reduced by 69.8%;(4)the optimal KH-560 addition is 1%.

Key words: silane coupling agent, ladles, carbon-free, corrosion resistance, coatings

摘要： 针对钢包耐火材料无碳化需求,以煅烧α-Al₂O₃粉、钇稳定氧化锆为涂层填料,加入镁铝质结合剂,以硅烷偶联剂(KH-560)为分散剂,制备涂层料浆,刷涂在40 mm×40 mm×10 mm的刚玉-镁铝尖晶石基体表面,经1 600 ℃保温1 h热处理制得涂层试样。研究了KH-560添加量(涂层填料质量的0、0.5%、1%、1.5%、2%、2.5%和3%)对涂层料浆性能及涂层试样抗侵蚀性的影响。结果表明:1)常温条件下,KH-560与羟基化Al₂O₃表面脱水缩合形成均匀的吸附层,其空间位阻效应降低料浆表面张力和黏度,显著提升料浆的稳定性;2)1 600 ℃热处理后,KH-560与Al₂O₃通过化学键合生成莫来石晶相,增强涂层与基体间的结合强度;3)抗渣侵蚀试验显示,相较于未添加KH-560的涂层试样,添加1%(w)的KH-560的试样侵蚀界面骨料边缘保持完整形貌,基质无液相渗透,侵蚀指数较未添加KH-560的试样降低69.8%;4)KH-560的适宜添加量为1%(w)。

关键词: 硅烷偶联剂, 钢包, 无碳化, 抗侵蚀性, 涂层