Polythermal sections of the Al2O3-ZrO2-Y2O3 phase diagram

Polythermal sections of the Al₂O₃-ZrO₂-Y₂O₃ phase diagram confirm that the system is quasibinary and enable one to give a complete phase diagram for the system. The ternary eutectic Al₂O₃ + ZrO₂ (solid solution) + Y₃Al₅O₁₂ has the lowest melting point in the system, whose temperature is 1715°C. No single-phase regions for the ternary solid solutions have been identified, which indicates that Al₂O₃ is not soluble in solid solutions based on F-ZrO₂ and C-Y₂O₃. This gives theoretical evidence for the scope for making new ceramics in this ternary system, which may have a high level of mechanical characteristics.     

Solidus surface and phase equilibria during the solidification of alloys in the Al2O3-ZrO2-Y2O3 system

The projection of the solidus surface in the Al₂O₃-ZrO₂-Y₂O₃ phase equilibrium diagram was plotted. The scheme of alloy solidification indicates that the primarily congruent modes of phase transformation in the limiting binary systems are retained in the ternary system.Institute of Materials Science Problems, Ukrainian Academy of Sciences. Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 1/2(377), pp. 71–76, January–February, 1975.     

Amorphized powders of eutectic composition in the Al2O3-ZrO2(Y2O3) system

Translated from Poroshkovaya Metallurgiya, No. 1(325), pp. 4–8, January, 1990.     

Phase diagram of the Al2O3-ZrO2-Er2O3 system. iv. vertical sections

For better presentation of the Al₂O₃-ZrO₂-Er₂O₃ phase diagram over a wide temperature and concentration ranges, three vertical sections are plotted to show interactions in the ternary system. The Er₂O₃-(50 mole% Al₂O₃ · 50 mole% ZrO₂) bisector shows the Er₂O₃-enriched region of the Al₂O₃-ZrO₂-Er₂O₃ phase diagram and explains the mechanism of Er₂O₃ phase transformations X ? H ? A ? B. The 15 mole% ZrO₂ (15Z) isopleth shows the Al₂O₃-ZrO₂-Er₂O₃ structure within the region adjacent to the Al₂O₃-Er₂O₃ binary bounding system. The ZrO₂-ErAlO₃ bisector depicts the ternary system in the ZrO₂-enriched region. The vertical sections intersect each of the three triangulating sections of the ternary system and demonstrate the width variation in their two-phase regions.     

Phase diagram of the Al2O3-ZrO2-Sm2O3 system. II. Liquidus surface

A projection has been constructed for the liquidus surface on the plane of the concentration triangle for the Al₂O₃-ZrO₂-Sm₂O₃ phase diagram. There are no ternary compounds, or appreciable regions of solid solutions based on the components and the binary compounds. The liquidus surface is formed by nine fields of primary phase crystallization. There are five four-phase nonvariant peritectic equilibria, as well as two four-phase nonvariant eutectic equilibria, and one three-phase nonvariant eutectic equilibrium. As the ZrO₂ and SmAlO₃ phases interact with other phases by a eutectic mechanism, it is possible to combine the unique properties of the T and F solid solutions based on ZrO₂ with the properties of the other phases in the form of composites. __________ Translated from Poroshkovaya Metallurgiya, Nos. 3–4(448), pp. 28–35, March–April, 2006.     

Phase diagram of the Al2O3-ZrO2-Er2O3 system. II. Phase diagram liqiudus surface

The liquidus surface for the Al₂O₃-ZrO₂-Er₂O₃ phase diagram is projected for the first time onto a concentration triangle. No ternary compounds are found in the system. The liquidus surface is completed by eight primary crystallization fields. Four four-phase nonvariant eutectic equilibria, one four-phase nonvariant transformation equilibrium, and three three-phase nonvariant eutectic equilibria are found in the system. Since ZrO₂ interacts with other phases eutectically, the unique properties of ZrO₂-based T-and F-solid solutions can be combined with the properties of other phases of the ternary system in composite materials. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 1–2(453), pp. 64–71, 2007.     

液相等离子喷涂La2O3-Y2O3-ZrO2涂层的组织结构与性能

采用一定化学配比的ZrOCl2·8H2O、YCl3和LaCl3三种盐溶液合成前驱体溶胶作为等离子喷涂液体喂料,制备二元稀土氧化物氧化镧与氧化钇共稳定的氧化锆陶瓷涂层,并测试分析了该涂层的组织结构、高温相稳定性及隔热性能。结果表明,氧化镧与氧化钇共稳定的氧化锆陶瓷涂层具有良好的隔热性能及高温相稳定性。     

Oxidation Resistance of Fe-13Cr Alloy with Micro-Laminated （ZrO2-Y2O3 ） / （Al2O3-Y2O3 ） Films

Oxidationofmetalsoralloysathightemperatures canbetreatedasaspecialcaseofmetalliccorrosion,inwhichsolidphasesinteracteitherwithaliquid agentoragaseousagent.Toimprovetheresistance againsthigh temperatureoxidationandelectrochemical corrosionofmetals,thesurfa…     

Al2O3-Y2O3 Nano- and Micro-Composite Coatings on Fe-9Cr-Mo Alloy

Al2O3-Y2O3 nano- and micro-composite coatings were deposited on Fe-9Cr-Mo substrates by using sol-gel composite coating technology. The processing includes dipping samples in a sol-gel solution dispersed with fine ceramic powders, which are prepared by high-energy ball milling. High-resolution microscopy （FE-SEM） analyses show that the coating is composed of composite particle clusters with an average diameter of 1μm, and the coating is relatively dense without cracking during drying and sintering stages. XRD analyses show that the oxide coating is mainly composed of α-Al2O3 and γ-Al2O3. The oxidation tests performed at 600℃ in air show that the coatings are provided with much improved resistance against high temperature oxidation and scale spallation. It is indicated that nano-structured composite particles and reactive elements are integrated into the coatings, which plays an important role in preventing agglomeration of nano-particles and initiation of cracks.     

Phase diagram for the system CaO-Al2O3-ZrO2

Phase equilibria in the system CaO-Al₂O₃-ZrO₂ were studied to optimize nozzle composition for tundishes that are used in continuous casters of steel, by identifying the composition that minimizes clogging. Mixtures of CaO, Al₂O₃, and ZrO₂ with various compositions were equilibrated at 1873 and 1773 K and then quenched into water. X-ray diffraction analysis was used for phase identification, and electron probe microanalysis was employed to measure chemical compositions. On the basis of these and previous results, the eutectic and peritectic lines have been estimated. Based on the phase diagram, the optimal nozzle composition is CaO-saturated CaZrO₃.     

Al2O3-ZrO2-Yb2O3 phase diagram. II. Liquidus surface

The liquidus surface for the Al₂O₃-ZrO₂-Yb₂O₃ phase diagram is constructed for the first time. No ternary compounds are found in the system. The liquidus surface is completed by seven primary crystallization fields. Two four-phase invariant eutectic equilibria, two four-phase invariant transition equilibria, and one three-phase invariant eutectic equilibrium are found in the ternary system. Since ZrO₂ interacts with other phases eutectically, composite materials can combine the unique properties of ZrO₂-based T-and F-phases with the properties of other phases of the Al₂O₃-ZrO₂-Yb₂O₃ system.     

Phase diagram of the ZrO2-Y2O3-Sm2O3 system in the melting-point region

A polynomial method has been used to construct a model for the liquidus surface in the ZrO₂-Y₂O₃-Sm₂O₃ phase diagram; that surface is made up of four fields of primary crystallization for the following phases: solid solutions based on cubic (C) and hexagonal (H) Y₂O₃, cubic ZrO₂ with a structure of fluorite type F, and high-temperature cubic La₂O₃ (X). The ternary system has two nonvariant four-phase equilibria of incongruent type. __________ Translated from Poroshkovaya Metallurgiya, Nos. 7–8(450), pp. 60–67, July–August, 2006.     

Phase diagram of the Al2O3-ZrO2-Sm2O3 system. III. Solidus surface and phase equilibria in alloy crystallization

A projection has been constructed for the solidus surface in the Al₂O₃-ZrO₂-Sm₂O₃ phase diagram on the plane of the concentration triangle, which consists of seven isothermal three-phase fields corresponding to two nonvariant equilibria of eutectic type and five nonvariant equilibria of peritectic type, and also eight lineated surfaces for the end of crystallization of the binary eutectics. The highest temperature on the solidus surface is 2710°C, the melting point of pure ZrO₂, while the lowest is 1680°C, the temperature of the triple eutectic Al + F + SA. No ternary phases or appreciable regions of solid solutions based on the components and the binary compounds are observed. Data on the bounding binary systems, the liquidus and solidus surfaces have been used to construct the phase-equilibrium (melting) diagram together with a reaction scheme for the equilibrium crystallization of alloys in the Al₂O₃-ZrO₂-Sm₂O₃ system. __________ Translated from Poroshkovaya Metallurgiya, Nos. 5–6(449), pp. 56–64, May–June, 2006.     

Phase diagram of the Al2O3-ZrO2-Er2O3 system. III. Solidus surface and phase equilibria in alloy crystallization

The solidus surface for the Al₂O₃-ZrO₂-Er₂O₃ phase is projected for the first time onto the concentration triangle. It consists of five isothermal three-phase fields that correspond to four invariant eutectic equilibria, one invariant transformation equilibrium, and six ruled binary eutectic solidus surfaces. The highest solidus temperature in the system is 2710 °C, which is the melting point of pure ZrO₂, and the lowest is 1720°C, which is the melting point of the ternary eutectic AL + F + Er₃A₅. Neither ternary phases nor visible solid solution areas based on components and binary compounds are found in the system. Based on the data on bounding binary systems, liquidus, and solidus surfaces, the phase equilibrium diagram and reaction scheme for equilibrium crystallization of Al₂O₃-ZrO₂-Er₂O₃ alloys are constructed. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 5–6 (455), pp. 74–83, 2007.     

Phase equilibria in the system HfO2-Y2O3-La2O3 AT 1900°C

We have used x-ray phase analysis, electron-probe microanalysis, petrography, and electron microscopy on annealed specimens to study phase equilibria in the ternary system HfO₂-Y₂O₃-La₂O₃ at 1900 °C over the entire concentration range. We have plotted the isothermal cross section of the phase diagram for this system at the indicated temperature. We found 23 phase regions. A typical feature of the system is formation of solid solutions based on different crystal modifications of the starting components (A-and H-La₂O₃, C-Y₂O₃, T-and F-HfO₂) and also the compounds La₂Hf₂O₇, LaYO₃. We did not observe new phases in the system. The nature of the phase equilibria in the system is consistent with the high relative thermodynamic stability of lanthanum hafnate (ΔH °La₂Hf₂O₇ ≈ 100 kJ/mole) compared with LaYO₃. We established that adding a third component extends the thermal stability region for the ordered phase of LaYO₃ toward higher temperatures. __________ Translated from Poroshkovaya Metallurgiya, Nos. 1–2(447), pp. 73–87, January–February, 2006.