烧结工艺对50%Mo-ZrO_2金属陶瓷结构与耐蚀性能的影响

Effect of sintering process on structure and corrosion resistance property for 50%Mo-ZrO_2 cermet

以钼粉及氧化锆粉为原料，采用不同的烧结工艺参数，在常压氩气气氛下烧结制备50%Mo-ZrO2金属陶瓷。采用四电极法测量该金属陶瓷的高温电导率，在1580℃下进行钢液和碱性熔渣侵蚀实验。结果表明：在烧结温度为1600～1650℃，保温时间为2～4 h的条件下，随保温时间延长或烧结温度升高，烧结体更加致密，孔隙率下降；因而金属陶瓷的电导率提高，耐钢液和熔渣侵蚀性增强；在1600℃、保温4 h条件下烧结的试样密度最大（6.49 g/cm^3），高温电导率最高（1600℃下的电导率为101 S/cm），耐钢液和熔渣侵蚀能力最强。钢液对金属陶瓷的侵蚀主要为Fe和Mo的相互溶蚀，熔渣对金属陶瓷的侵蚀主要作用于ZrO2陶瓷相，熔渣中的Al2O3取代金属陶瓷中的ZrO2。熔渣侵蚀过程中，CaO与金属陶瓷中的ZrO2发生反应生成高熔点CaZrO3相，阻止熔渣对金属陶瓷的进一步侵蚀。

50%Mo-ZrO2 cermet was prepared using Mo powder and ZrO2 powder as raw materials under the condition of aragon protection with different sintering process parameters. Electrical conductivity properties of 50%Mo-ZrO2 samples at high temperature were measured using four-electrode method. The sample was corroded by molten steel and basic slag at 1 580 ℃ respectively. The results indicate that while the sintering temperature is varied from 1 600℃to 1 650℃, and hold for 2 h to 4 h, increasing sintering time or enhancing the sintering temperature leads the density of cement increase and the high-temperature electrical conductivity decrease, and thus enhances the corrosion resistance of the samples against molten steel and slag. When the sample is sintered at 1 600 ℃ and hold for 4 h , there is the a maximum density of 6.49 g/cm3 approximately and the maximum high-temperature electrical conductivity value approximately 101 S/cm, respectively, and the sample has the best corrosion resistance to molten steel and molten slag as well. The main role of the molten steel corrosion is the dissolution between Fe and Mo, the main role of the basic slag is the reaction between ZrO2 phase and slag component, and the Al2O3 in slag takes a part in replacing the ZrO2 ceramic phase in the samples. Besides, CaO in slag reacts with ZrO2 in the samples to generate the phase of CaZrO3, which can prevent samples from further corroding by slag.