High temperature-resistant palladium-modified aluminide coatings for nickel-base superalloys
High temperature-resistant palladium-modified aluminide coatings for nickel-base superalloys
复制标题
镍基高温合金用耐高温钯改性铝化物涂层
DOI：
10.1016/0921-5093(89)90789-2
复制
发表时间：
1989
期刊：
影响因子：
6.4
通讯作者：
A. Costantini
中科院分区：
文献类型：
--
作者：
S. Alperine;P. Steinmetz;P. Josso;A. Costantini
铂改性铝化物涂层表现出更好的耐高温腐蚀性能。铂金属的高价格促使人们对钯修饰铝化物涂层的潜力进行了研究。在本文中，我们发现文献报道的PdAl涂层耐热腐蚀性能差的主要原因是工艺不当，导致涂层中大量的氢进入涂层并随后形成气孔和水泡。这可以通过用Pd-20wt.%Ni合金预沉积来代替纯Pd预沉积来避免，在Pd-20wt.%Ni合金中，氢的溶解度要低得多。利用这一新技术，在IN100上获得了内向型和外向型Pd--Ni改性铝化物涂层。它们的结构由单一的β(Pd，Ni)-Al相组成，在整个涂层厚度上具有很强的钯浓度梯度。涂层外层的成分为(Ni0.4，Pd0.6)-Al。这些涂层在85 0℃空气中和空气+0.0 1%SO2，周期性Na2SO4污染(每501h循环0.5mgcm−2)下进行腐蚀试验。所有含钯涂层在这种环境下都表现出优异的耐受性(使用寿命超过1000次)。在1100℃下进行的循环氧化试验还表明，钯对保护氧化铝膜的完整性和粘附性具有良好的效果。到目前为止所获得的结果表明，在相同的测试条件下，钯铝化物涂层的性能至少与典型的铂改性铝化物涂层相当。
Platinum-modified aluminide coatings have shown increased resistance to high-temperature corrosion. The high price of platinum metal has motivated investigations of the potential for palladium-modified aluminide coatings. In this paper, we have shown that the poor hot corrosion resistance of PdAl coatings reported in the literature was mainly due to inadequate processing, leading to significant incorporation of hydrogen into the coating and the subsequent formation of pores and blisters. This can be avoided by replacing a pure palladium predeposit by a Pd-20wt.% Ni alloy predeposit in which hydrogen is far less soluble. By this new technique, PdNi-modified aluminide coatings of the inward and outward type were obtained on IN 100. Their structure consists of a single β(Pd, Ni)-Al phase, with a strong palladium concentration gradient across the coating thickness. The composition in the outer part of the coating corresponds to (Ni0.4, Pd0.6)-Al. Corrosion tests were performed on these coatings at 850°C in air and in air + 0.01% SO2, with periodic Na2SO4contamination (0.5 mg cm−2every 50 1 h cycles). All palladium-containing coatings showed an excellent resistance to this environment (lifetime greater than 1000 cycles). Cyclic oxidation tests performed at 1100 °C also showed a beneficial effect of palladium on the protective Al2O3scale integrity and adhesion. The results obtained so far indicate that palladium aluminide coatings behave at least as well as typical platinum-modified aluminide coatings under the same testing conditions.