Tairoring Amorphous Surface Alloys Resistant against High Temperature Corrosion

这项工作的目标之一是定制非晶表面合金的常规金属溅射沉积，以保护底层的常规金属在高温下的硫化和氧化。从非晶态合金前驱体中定制用于氯氟烃水解的活性催化剂是本工作的另一个目的。我们成功地制备了具有高抗硫化和抗氧化性能的Al-Mo、Al-Nb和Al-Ta非晶合金。此外，还获得了少量硅的上述合金，以进一步提高氧化电阻率。这是腐蚀科学史上第一次获得与抗氧化常规合金的氧化速率相当的低硫化速率的合金。这些合金表面形成的硫化物膜由外层的硫化铝层和内层的难熔金属硫化物层组成，后者具有很高的保护性， 关于我们 抗硫化。非晶态合金在发生硫化和氧化的高温下转化为金属间化合物，但细晶粒金属间化合物的形成是合金与基材金属更好粘附的原因。在高温下，合金中所含的硅与合金中的难熔元素形成硅化物，并且因为硅化物对氧化稳定，所以硅的存在抑制了难熔元素的氧化。在304不锈钢上成功地制备了非晶态表面合金，在高温下对硫化和氧化都有很好的保护作用。在氟氯化碳CCl_2F_2水解成CO_2、HCl和HF的催化分解过程中，催化剂必须暴露于非常强的分解产物中。由含有少量铬、钼或钨的非晶态Ni-Zr合金前驱体进行催化反应，获得了活性和耐久性好的催化剂。少

One of the objectives of this work is to tailor amorphous surface alloys on conventional metals by sputter deposition in order to protect the underlying conventional metals against sulfidation and oxidation at high temperatures. Tailoring active catalysis from amorphous alloy precursors for hydrolytic decomposition of cholorofluorocarbon is another aim of this work. We succeeded to prepare amorphous Al-Mo, Al-Nb and Al-Ta alloys with high resistance against both sulfidation and oxidation. In addition, the above-mentioned alloys with small additions of silicon have been obtained for further enhancement of oxidation resisitance. It is the first time on the history of corrosion science that the alloys with low sulfidation rates which are comparable to the oxidation rates of oxidation-resistant conventional alloys are obtained. Sulfide scales formed on these alloys consist of an outer aluminum sulfide layr and an inner refractory metal sulfide layr, the latter of which has high protectiven … More ess against sulfidation. The amorphous alloys are converted to intermetallics at high temperatures where sulfidation and oxidation take place, but the formation of fine grained intermatallics is responsible for better adhesion of the alloys to the substrate metals. Silicone contained in the alloys form silicides with refractory elements in the alloys at high temperatures, and because the silicides are stable against oxidation, the presence of silicon suppresses oxidation of refractory elements. Amorphous surface alloys have been successfully prepared on 304 stainless steel and show high protectiveness against both sulfidation and oxidation at high temperatures.In the catalytic decomposition of a cholorofluorocarbon CCl_2F_2 by hydrolysis into CO_2, HCl and HF the catalyst should be exposed to very aggressive decomposition products. The active and durable catalysts have been obtained as a result of the catalystic reaction from amorphous Ni-Zr alloy precursors containing small amounts of chromium, molybdenum or tungsten. Less