硅酸盐学报

氧化镁坩埚与镍基高温合金界面反应机理

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陈光耀 ¹^,² , 廖厚劲 ¹ , 邓少文 ¹ , 冯齐胜 ¹ , 高鹏越 ¹ , 王恩会 ³ , 赵云松 ⁴ , 侯新梅 ³ , 李重河 ¹^,²

硅酸盐学报 | 研究论文 2024,52(12): 3832-3840

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硅酸盐学报 |研究论文 2024 , 52 (12) : 3832 -3840

氧化镁坩埚与镍基高温合金界面反应机理

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陈光耀¹^,², 廖厚劲¹, 邓少文¹, 冯齐胜¹, 高鹏越¹, 王恩会³, 赵云松⁴, 侯新梅³, 李重河¹^,²

作者信息

^1．上海大学材料科学与工程学院，省部共建高品质特殊钢冶金与制备国家重点实验室，上海市钢铁冶金新技术开发应用重点实验室，上海 200072

^2．上海市特种铸造工程技术研究中心，上海 201605

^3．北京科技大学碳中和研究院，北京 100083

^4．北京航空材料研究院先进高温结构材料重点实验室，北京 100095

通讯作者:

侯新梅（1979—），女，博士，教授。

李重河（1962—），男，博士，教授。

作者简介:

陈光耀（1987—），男，博士，副教授。

Interaction Mechanism Between MgO Crucible and Ni-Based Superalloy

Guangyao CHEN¹^,², Houjin LIAO¹, Shaowen DENG¹, Qisheng FENG¹, Pengyue GAO¹, Enhui WANG³, Yunsong ZHAO⁴, Xinmei HOU³, Chonghe LI¹^,²

Affiliations

^1.State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy, School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China

^2.Shanghai Special Casting Engineering Technology Research Center, Shanghai 201605, China

^3.Institute for Carbon Neutrality, University of Science and Technology Beijing, Beijing 100083, China

^4.Science and Technology on Advanced High Temperature Structural Materials laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China

Corresponding Author:

HOU Xinmei (1979-), female, Ph.D., Professor. E-mail: houxinmeiustb@ustb.edu.cn;

LI Chonghe (1962-), male, Ph.D., Professor. chli@staff.shu.edu.cn

CHEN Guangyao (1987-), male, Ph.D., Associate Proressor. E-mail: cgybless1@shu.edu.cn

出版时间: 2024-12-20 doi: 10.14062/j.issn.0454-5648.20240387

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摘要

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坩埚式感应熔炼镍基高温合金的纯净度与合金-坩埚界面反应程度密不可分，明确两者界面反应机理对实现高纯净度合金制备具有重要意义。采用MgO坩埚分别感应熔炼纯Ni和镍基高温合金，通过X射线衍射仪、扫描电子显微镜及氧/氮分析仪研究了坩埚与金属熔体接触前后相组成、显微形貌及金属中氧含量的变化规律，进而研究了2种金属与MgO坩埚间界面反应，明晰了界面反应机理。研究表明：使用MgO坩埚熔炼纯Ni时，纯Ni熔体对坩埚内壁润湿，但并未见明显界面反应发生。而高温合金熔体与MgO坩埚存在界面反应，该反应以MgO在合金熔体中熔解-分解为主，分解O与熔体中Al反应形成Al₂O₃，其中：一部分Al₂O₃会上浮至合金表面；另一部分Al₂O₃会与MgO坩埚基体反应生成MgAl₂O₄，同时，该生成物一部分附着在坩埚内壁；另一部分也受电磁搅拌进入合金表面，最终在合金表面形成由Al₂O₃，MgAl₂O₄和一部分合金混合而成的厚度约80 μm的浮渣层。

关键词

坩埚 / 感应熔炼 / 镍基高温合金 / 界面反应 / 浮渣

Abstract

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Introduction

The purity of the Ni-based superalloy is directly related to the alloy-crucible interaction during induction melting. It is thus of great significance to clarify the interaction mechanism for the achievement of preparing the high-purity superalloys. In this study, pure Ni and Ni-based superalloys were melted in MgO crucibles, respectively. The phase composition, microstructure of the crucible and the oxygen concentration of the metals were analyzed by scanning electron microscopy, X-ray diffractometry and O/N analyzer. The interaction between the metals and the crucibles were investigated, and the interaction mechanism was elucidated. The results indicate that after melting pure Ni in MgO crucible, pure Ni melt exhibits a good wettability to the crucible, but little interaction occurs. However, a significant interaction between the superalloy melt and MgO crucible occurs. This reaction primarily involves the dissolution and decomposition of MgO in the alloy melt. The decomposed element O reacts with element Al to form Al₂O₃ products, which can float to the surface of the superalloy. Also, some Al₂O₃ can further react with MgO crucible matrix to generate MgAl₂O₄ product, which can attach to the inner surface of the crucible, and float into the slag, respectively. A slag layer with the thickness of approximately 80 μm composed of Al₂O₃, MgAl₂O₄, and a portion of the alloy can be formed on the surface of the alloy.

Methods

In this study, an industrial grade MgO (purity>99.5%) was used as a raw material. The MgO powder was mixed and ground in ethanol in a concrete mixer with yttria stabilized zirconia (YSZ) balls at a speed of 300 r/min. The mass ratio of powders, YSZ balls and ethanol were 3.0 ∶ 5.0 ∶ 0.8. The ground powder was then dried in an oven for 12 h. The MgO crucible green body was fabricated via cold isostatic pressing at 150 MPa for 3 min. Subsequently, the green body was sintered in a high-temperature silicon molybdenum rod sintering furnace at 1 750 ℃ for 6 h. The outer diameter, inner diameter, and height of the sintered crucible are 60, 50 and 70 mm, respectively.

An electrolytic pure Ni and DD419 alloy was used as an experimental metal. Pure Ni of 100 g was ground and acid pickled. The DD419 alloy was cut into 2 cm×2 cm×4 cm block caret, and its weight was 120 g. After grinding and acid pickling, the alloy was used as an experimental metal. The sintered MgO crucible was placed in a coil of a vacuum induction melting furnace, and filled with fused MgO sand around the crucible. It could prevent the short circuit of the induction coil due to the leakage of the molten metal. The experimental metal was inserted into the crucible, and the furnace was evacuated with a mechanical pump and a molecular pump to approximately 1×10^-2 Pa. The furnace was backfilled with high-purity argon to 0.06 MPa, and repeated for three times in order to eliminate the influence of the residual oxygen. The melting experiment was conducted in high vacuum. The metal temperature was raised slowly until the appearance of the liquid at the bottom of the metal. The temperature of the molten metal rapidly increased to 1 550 ℃, and hold at this temperature for 20 min. Finally, the molten melts were cooled in the crucibles to obtain the corresponding samples. After melting, the samples were cut via wire-electrode cutting and polished for the coming use.

Results and discussion

The surface of pure Ni after melting in the MgO crucible is smooth without the appearance of the impurities. However, the surface of the superalloy has a black slag layer with a thickness of 80 μm, indicating that the slag is formed during the interaction between the alloy and the crucible. The surface of the slag can form a wrinkled shape due to the difference in the cooling rate between the slag and the alloy melt. No corrosion phenomenon occurs on the surface of the crucible after melting pure Ni. However, some Ni melt is residual on the surface of the crucible due to the wettability. In contrast, after melting the alloy in the crucible, the grain morphology and grain boundaries on the surface of the crucible disappear, indicating that the surface of the crucible is corroded by the alloy melt, thus leading to the generation of MgAl₂O₄ products. The slag primarily consists of Al₂O₃ and MgAl₂O₄ as well as some residual alloy melt, respectively. The generation of Al₂O₃ and MgAl₂O₄ products is attributed to the reaction at the melt-crucible interface. These products can float into the surface of the alloy melts under the electromagnetic stirring because Al₂O₃ and MgAl₂O₄ products have a lower density than that of the alloy melts. The thermodynamic stability for Al₂O₃, MgO, Cr₂O₃ and NiO indicates that element Al in the alloy has an intense affinity for element O, leading to the dissolution of MgO refractory and the oxygen contamination of the alloy melt. The uneven distribution of MgAl₂O₄ in both the inner surface of the crucible and the slag exhibits that the interaction and electromagnetic stirring significantly affect the formation of the slag.

Conclusions

Pure Ni did not react with MgO crucible. However, DD419 alloy could exhibit a significant interaction with the crucible, resulting in the alloy contamination and the formation of a slag layer. The thickness of the slag layer was 80 μm, and it consisted of Al₂O₃, MgAl₂O₄ and some alloy. In addition, Al₂O₃ and MgAl₂O₄ were the interaction products between the alloy melt and the crucible. The dissolution of MgO refractory could result in the release of elements Mg and O, respectively. Element Al reacted with element O to generate Al₂O₃ products. A portion of the products could float, and another part could react with MgO matrix on the inner wall of the crucible to form MgAl₂O₄. Meanwhile, some of the generated MgAl₂O₄ was adhered to the inner wall of the crucible, and another portion was floated into the slag layer.

Key words

crucible / induction melting / nickel -based superalloy / interaction / slag

引用本文

陈光耀, 廖厚劲, 邓少文, 冯齐胜, 高鹏越, 王恩会, 赵云松, 侯新梅, 李重河. 氧化镁坩埚与镍基高温合金界面反应机理. 硅酸盐学报, 2024 , 52 (12) : 3832 -3840 . DOI: 10.14062/j.issn.0454-5648.20240387

Guangyao CHEN, Houjin LIAO, Shaowen DENG, Qisheng FENG, Pengyue GAO, Enhui WANG, Yunsong ZHAO, Xinmei HOU, Chonghe LI. Interaction Mechanism Between MgO Crucible and Ni-Based Superalloy[J]. Journal of the Chinese Ceramic Society, 2024 , 52 (12) : 3832 -3840 . DOI: 10.14062/j.issn.0454-5648.20240387

基金

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国家重点研发计划(2022YFB3404501)
国家自然科学基金(52374360; U2341267; 52104305)

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2024年第52卷第12期

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文章信息

doi: 10.14062/j.issn.0454-5648.20240387

接收时间：2024-06-03
首发时间：2026-10-22
出版时间：2024-12-20

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收稿日期：2024-06-03
修回日期：2024-07-08

基金

国家重点研发计划(2022YFB3404501)

国家自然科学基金(52374360; U2341267; 52104305)

作者信息

^1．上海大学材料科学与工程学院，省部共建高品质特殊钢冶金与制备国家重点实验室，上海市钢铁冶金新技术开发应用重点实验室，上海 200072

^2．上海市特种铸造工程技术研究中心，上海 201605

^3．北京科技大学碳中和研究院，北京 100083

^4．北京航空材料研究院先进高温结构材料重点实验室，北京 100095

通讯作者:

侯新梅（1979—），女，博士，教授。

李重河（1962—），男，博士，教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20240387

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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