不锈钢表面SiO_2-ZrO_2-Al_2O_3-Cr_2O_3陶瓷涂层性能的研究

Properties of SiO_2-ZrO_2-Al_2O_3-Cr_2O_3 coatings on stainless steel substrate

将氧氯化锆、正硅酸乙脂、无水乙醇3种物质按物质的量比135放进烧杯搅拌均匀后,再放进微波炉加热10s取出,得到SiO2-ZrO2溶胶。然后,将100mL氨水、50mL硝酸铝溶液和50mL硝酸铬溶液混合均匀后,放进微波炉加热1min后取出,即制得Al2O3-Cr2O3溶胶。取SiO2-ZrO2溶胶和Al2O3-Cr2O3溶胶按n（SiO2）n（ZrO2）n（Al2O3）n（Cr2O3）=6211混合,搅拌2h,得到SiO2-ZrO2-Al2O3-Cr2O3复合溶胶。将打磨、除锈、除油处理后的不锈钢基体浸入SiO2-ZrO2-Al2O3-Cr2O3溶胶一定时间后,以浸渍提拉法得到均匀的溶胶涂层,真空干燥48h,经700℃热处理1h后便可得到SiO2-ZrO2-Al2O3-Cr2O3复合陶瓷涂层。采用XRD、IR和SEM对不同条件热处理的复合陶瓷涂层的物相组成、表面形貌进行分析,并对复合陶瓷涂层的性能进行了研究。结果表明（1）SiO2-ZrO2-Al2O3-Cr2O3复合溶胶热处理后为非晶态材料,且在凝胶中形成了三维的硅氧四面体网络骨架;（2）涂层试样不出现龟裂或脱落的循环次数（900℃,空冷）在15-30次范围内，涂层的抗热震性较好；（3）在700℃热处理1h条件下，涂层单位面积的质量损失最小，具有较好的抗腐蚀性；（4）有涂层试样较无涂层试样的氧化速率低，且以3次涂膜的氧化速率最低；涂层由粒径为2—3μm左右的微粒组成，涂层较致密，抗氧化性较好；（5）有涂层试样的耐磨性均优于无涂层试样，有涂层试样的以3次涂膜的耐磨性最好。

First, SiO2-ZrO2 sol was prepared by mixing the analytical reagent ZrOCl2·8H2O,TEOS and anhydrous ethanol with mole ratio 1：3：5 and heating for 10 seconds by microwave. Second, Al2O3-Cr2O3 sol was prepared by mixing 100 mL NH3·H2O,50 mL Al（NO3）3·9H2O and 50 mL Cr（NO3）3·9H2O and heating for 1 min by microwave.Then,the SiO2-ZrO2-Al2O3-Cr2O3 compound sol was finally prepared by mixing for 2 h the SiO2-ZrO2 sol and Al2O3-Cr2O3 sol with ratio n（SiO2） ： n（ZrO2） ： nAl2O3） ： n（Cr2O3）=6：2：1：1.The pretreated substrate （ground,de-rusted and de-oiled） was soaked in SiO2 -ZrO2 -Al2O3 -Cr2O3 sol for a while,and the compound ceramic coating was then obtained on the surface by dip-coating method,vacuum drying for 48 h and firing at 700 ℃ for 1h. The SiO2 -ZrO2 -Al2O3 -Cr2O3 film was coated on the surface of stainless steel by dip-coating method,freeze drying for 48 h and heating at 700 ℃ for 1 h. The phase composition, surface morphology of coatings heated under different conditions were analyzed by XRD, IR spectra and SEM,and the properties were studied. The results showed that= （1）The SiO2 - ZrO2 -Al2O3 -Cr2O3 compound sol after heat treatment had non-crystalline structure,which was formed as three -dimensional Si-O tetrahedron skeleton. （2）The thermal shock resistance of the coatings were well performed, reaching within 15 -30 cycles （900 ℃,air cooling） before cracking and spalling. （3）The coated specimens had the best corrosion resistance after firing at 700℃ for 1 h. （4）The oxidation ratio of coated specimens was lower than those uncoated. The 3 times coated specimen performed the best in the respect. The ceramic coating composed of 2 -3μm grains was dense and oxidation resistant. （5）The coated stainless steel substrates had better abrasion resistance than those uncoated. And the three times coated specimens performed the best.