三维网络结构SiC-Fe复合材料制备及腐蚀性能研究

Preparation and Corrosion Properties of Iron Matrix Composites Reinforced by SiC with 3D Network Structure

传统钢铁材料难以满足深井开采严苛的腐蚀环境,亟需开发具有良好耐蚀性的新材料。SiC陶瓷具有优异的耐蚀性,因此探讨了以SiC为原材料的复合材料的制备及耐蚀性。以SiC、Al_(2)O_(3)、Si O_(2)为原材料采用有机泡沫浸渍法制备出三维网络结构SiC陶瓷,并采用浇铸工艺制备三维网络结构SiC-Fe复合材料,采用扫描电子显微镜、X射线衍射仪等对Si C-Fe复合材料组织结构及物相进行分析,通过电化学试验、浸泡试验对SiC-Fe复合材料的耐蚀性进行表征,并分析其耐腐蚀机制。结果表明:SiC-Fe复合材料中SiC陶瓷增强体与高铬铸铁基体之间未发生元素扩散,界面结合方式为机械结合,基体中主要物相有奥氏体和碳化物,陶瓷增强体中主要为六方结构Si C和Al_(2)O_(3);Si C陶瓷增强体的加入使高铬铸铁的腐蚀电流由4.189×10^(-3)A/cm^(2)降至3.353×10^(-3) A/cm^(2),电荷转移电阻从7309Ω·cm^(2)增大至11881Ω·cm^(2),电容值从1.994×10^(-4)F/cm^(2)降至1.974×10-5 F/cm^(2),使整体的耐蚀性得到了提高。浸泡试验表明,SiC-Fe复合材料的腐蚀主要发生在高铬铸铁基体部分,界面及SiC陶瓷增强体处不易发生腐蚀;与纯高铬铸铁材料相比,SiC-Fe复合材料点蚀产生的时间较晚且腐蚀程度相对较轻。研究成果为复合材料在煤矿深井开采装备的应用提供重要理论依据。

Traditional iron and steel materials are difficult to meet the harsh corrosion environment of deep well mining,so it is urgent to develop new materials with good corrosion resistance.SiC ceramic has excellent corrosion resistance.There-fore,the preparation and corrosion resistance of SiC based composites were discussed.Three-dimensional network structure SiC ceramics were prepared by organic foam impregnation method using SiC,Al_(2)O_(3),SiO_(2)as raw materials,and three-di-mensional network structure SiC-Fe composites were prepared by casting process.The microstructure and phase of SiC-Fe composites were analyzed by scanning electron microscope and X-ray diffractometer.The corrosion resistance of SiC-Fe composites was characterized by electrochemical test and immersion test,and its anti-corrosion mechanism was analyzed.The results show that there is no element diffusion between SiC ceramic reinforcement and high-chromium cast iron matrix in SiC-Fe composites,and the interface bonding mode is mechanical bonding.The main phases in the matrix are austenite and carbides,the ceramic reinforcement is mainly composed of hexagonal SiC and Al_(2)O_(3).The addition of SiC ceramic rein-forcement reduces the corrosion current of high-chromium cast iron from 4.189×10^(-3)A/cm^(2)to 3.353×10^(-3) A/cm^(2),in-creases charge transfer resistance from 7309Ω·cm^(2)to 11881Ω·cm^(2),and reduces the capacitance values from 1.994×10^(-4)F/cm^(2)to 1.974×10^(-5) F/cm^(2),which improves the overall corrosion resistance.The immersion test shows that the corro-sion of SiC-Fe composites mainly occurs in the high-chromium cast iron matrix,and the interface and SiC ceramic rein-forcement are not prone to corrosion.Compared with high-chromium cast iron materials,the pitting corrosion of SiC-Fe composites occurs later and the corrosion degree is relatively light.The research results provide an important theoretical ba-sis for the application of composite materials in deep coal mining equipment.