炭砖在混合硝酸熔融盐中的腐蚀行为

Corrosion behavior of carbon bricks in mixed molten nitrate salts

对6种常用炭砖在两种混合硝酸熔融盐中的腐蚀行为进行了研究,借助金相显微镜观察腐蚀前后试样表面形貌,用X射线衍射仪(XRD)分析腐蚀产物成分,并从炭砖的基本性能出发,对其在混合硝酸熔盐中的腐蚀规律进行了探讨。结果表明,炭砖在空气中的传热性能对其在熔融盐传热系统中的应用十分有利,但使用温度不能超过其起始氧化温度,炭砖的石墨化度、气孔率等都会影响到抗腐蚀性,炭砖在400℃及更低温度下的混合硝酸熔融盐中的腐蚀不属于化学腐蚀,主要是物理性破坏。

The corrosion behaviors of six kinds of carbon bricks in mixture of NaNO3, NAN02 and KNO3 were evaluated to find the suitable material as applicable to an advanced solar thermal energy system. Carbon bricks were examined by the thermal gravimetric analyzer, surface morphologies of samples were investigated by optical microscope, corrosion products were analyzed by X-ray diffraction （XRD）, and meanwhile the carbon materials corrosion rule and mechanism from its properties were discussed. Results indicated that carbon bricks used as a heat transfer material was very favorable, but the used temperature should not exceed their initial oxidation temperature. The graphitization degree and porosity of carbon products have great influence on resistance to corrosion of carbon materials. The corrosion below 400℃ was not caused by the chemical reaction, but the physical damage.