MCPT-4型金属陶瓷在熔盐中腐蚀行为研究

实验研究MCPT-4型金属陶瓷材料在BaCl 2熔盐中的腐蚀行为，并对现场使用后的金属陶瓷保护管取样分析。结果表明，MCPT-4型金属陶瓷在高温盐浴炉中应用是成功的，它是耐BaCl 2熔盐腐蚀的较好材料。在BaCl 2熔盐中蚀损的主要原因是钼的电化学腐蚀，基腐蚀速度随钼含量的增加而加快。在金属陶瓷中添加Cr 2O 3可提高抗腐蚀性能。本文研究结果可为金属陶瓷保护管的研制及现场合理使用提供依据。

CORROSION BEHAVIOR OF MCPT-4 CERAMETS IN MOLTEN SALTS

A systematic investigation was made on the corrosion behavior of MCPT-4 ceramets in high-temperature molten salts. A criterion is thus developed for the preparation and application of such ceramets’ protection tubes to thermocouples. Ceramets of ternary system MCPT-4 or of quarternary system in which other component is added are proved extraordinarily beneficial to the resistance to BaCl2 molten salt with a continuous service life not less than 1400h. Their corrosion losses are mainly due to the electrochemical corrosion to metallic molybdenum at a corrosion rate increasing with Mo content. Therefore, the molybdenum content in ceramet should be decreased as possible to provide it with enough resistance to corrosion, subject to satisfaction of the resistance to thermal shock given to ceramet protection tube. After sintered in H2 atmosphere at 1800℃, a part of Cr2O3 in MCPT-4 ceramets will be reduced to metallic chromium and then forming solid solution together with molybdenum. The additive Cr2O3 in Mo-Al2O3 system will serve the function of bridge or tie to strengthen the combination of metallic phase with ceramic phase, thus improving the properties of ceramets.