{"title":"Synthesis of Lanthanum Pyrochlore–Lanthanum Phosphate Composite Powders for Thermal Barrier Coating Applications","authors":"K. Karthikeyan, S. Manisha Vidyavathy","doi":"10.1007/s11106-024-00429-1","DOIUrl":null,"url":null,"abstract":"<p>Thermal barrier coatings (TBCs) play a critical role in protecting metallic substrates from high-temperature degradation in aerospace and industrial applications. This study was undertaken to synthesize and evaluate a novel lanthanum phosphate zirconate (LaPZ) composite as a potential candidate for TBCs. The LaPZ composite was synthesized by a high-energy ball milling method followed by calcination, which allows precise control over the composition and microstructure. The synthesized LaPZ composite was characterized by various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermal analysis. Lanthanum phosphate was prepared by precipitation method: calcined at 700°C and further calcined at 1,200°C for 2 h. LP-C was used for the preparation of composite powders. It was ball milled at 350 rpm for 8 h, wet milled with distilled water in a high energy planetary mill with zirconia media, and calcined at 1,300°C for 4 h. X-ray diffraction analysis at 1,300°C revealed LaPZ composite powders with a cubic pyrochlore structure of La<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> and monoclinic LaPO<sub>4</sub>. To obtain the pyrochlore structure, LaP and zirconia were taken in two different molar ratios, namely 1 : 1 (LaPZ 1) and 1 : 2 (LaPZ 2). The coefficient of thermal expansion (CTE) of the LaPZ 1 coating was approximately 8.97 · 10<sup>–6</sup> K<sup>–1</sup>. The LAPZ 2 coating exhibited a CTE of 9.15 · 10<sup>–6</sup> K<sup>–1</sup> when exposed to temperatures ranging from 0 to 1,400°C. Samples maintained stable thermal expansion up to 1,400°C, indicating the suitability of LaPZ for TBC applications.</p>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"62 11-12","pages":"712 - 721"},"PeriodicalIF":0.9000,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Powder Metallurgy and Metal Ceramics","FirstCategoryId":"88","ListUrlMain":"https://link.springer.com/article/10.1007/s11106-024-00429-1","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATERIALS SCIENCE, CERAMICS","Score":null,"Total":0}
引用次数: 0
Abstract
Thermal barrier coatings (TBCs) play a critical role in protecting metallic substrates from high-temperature degradation in aerospace and industrial applications. This study was undertaken to synthesize and evaluate a novel lanthanum phosphate zirconate (LaPZ) composite as a potential candidate for TBCs. The LaPZ composite was synthesized by a high-energy ball milling method followed by calcination, which allows precise control over the composition and microstructure. The synthesized LaPZ composite was characterized by various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermal analysis. Lanthanum phosphate was prepared by precipitation method: calcined at 700°C and further calcined at 1,200°C for 2 h. LP-C was used for the preparation of composite powders. It was ball milled at 350 rpm for 8 h, wet milled with distilled water in a high energy planetary mill with zirconia media, and calcined at 1,300°C for 4 h. X-ray diffraction analysis at 1,300°C revealed LaPZ composite powders with a cubic pyrochlore structure of La2Zr2O7 and monoclinic LaPO4. To obtain the pyrochlore structure, LaP and zirconia were taken in two different molar ratios, namely 1 : 1 (LaPZ 1) and 1 : 2 (LaPZ 2). The coefficient of thermal expansion (CTE) of the LaPZ 1 coating was approximately 8.97 · 10–6 K–1. The LAPZ 2 coating exhibited a CTE of 9.15 · 10–6 K–1 when exposed to temperatures ranging from 0 to 1,400°C. Samples maintained stable thermal expansion up to 1,400°C, indicating the suitability of LaPZ for TBC applications.
期刊介绍:
Powder Metallurgy and Metal Ceramics covers topics of the theory, manufacturing technology, and properties of powder; technology of forming processes; the technology of sintering, heat treatment, and thermo-chemical treatment; properties of sintered materials; and testing methods.