Phase formation in multicomponent rare‐earth oxides is determined by a combination of composition, sintering atmosphere, and cooling rate. Polycrystalline ceramics comprising various combinations of Ce, Gd, La, Nd, Pr, Sm, and Y oxides in equiatomic proportions were synthesized using solid‐state sintering. The effects of composition, sintering atmosphere, and cooling rate on phase formation were investigated. Single cubic or monoclinic structures were obtained with a slow cooling of 3.3°C/min, confirming that rare‐earth oxides follow a different structure stabilization process than transition metal high‐entropy oxides. In an oxidizing atmosphere, both Ce and Pr induce a cubic structure, while only Ce plays that role in an inert or reducing atmosphere. Samples without Ce or Pr develop a single monoclinic structure. The structures formed at initial synthesis may be converted to a different one, when the ceramics are annealed in an additional atmosphere. Phase evolution of a five‐cation composition was also studied as a function of sintering temperature. The binary oxides used as raw materials completely dissolve into a single cubic structure at 1450°C in air.

中文翻译：

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多组分等原子稀土氧化物的固态合成

多组分稀土氧化物中的相形成取决于组成，烧结气氛和冷却速率。使用固态烧结法合成了以等原子比例包含Ce，Gd，La，Nd，Pr，Sm和Y氧化物的各种组合的多晶陶瓷。研究了组成，烧结气氛和冷却速率对相形成的影响。以3.3°C / min的慢速冷却获得了单立方或单斜晶结构，这证实了稀土氧化物与过渡金属高熵氧化物遵循的结构稳定过程不同。在氧化性气氛中，Ce和Pr均会诱发立方结构，而在惰性或还原性气氛中只有Ce起作用。没有Ce或Pr的样品会形成一个单斜晶结构。当陶瓷在额外的气氛中退火时，初始合成时形成的结构可以转变为不同的结构。还研究了五阳离子组成的相变与烧结温度的关系。用作原料的二元氧化物在1450°C的空气中完全溶解成一个立方结构。