Oxidation resistance of Al/Si composite low-carbon stabilized MgO-CaO materials

doi:10.3969/j.issn.1001-1935.2021.05.012

Abstract

Abstract:

In order to improve the comprehensive utilization of refractory resources,the self-made stabilized magnesia dolomite composite material,fused magnesia,Al powder,Si powder,and flake graphite were used as raw materials to study the oxidation resistance of Al/Si composite low-carbon stabilized MgO-CaO materials,and to explore the relationship among the oxidation resistance,the phase composition and the microstructure.The results show that:(1)the oxidation mechanism of materials with Al/Si powder is obviously protective oxidation;(2)after oxidizing at 1 000 and 1 500 ℃ for 3 h respectively,the specimens without Al/Si powder are completely oxidized;the oxide layer thickness of the specimens with Al/Si powder reduces,and the oxidation resistance improves;the addition of Al powder can effectively improve the oxidation resistance of the material,the optimal Al powder addition is 4 mass%;the oxide layer thickness of the specimens with only Si powder does not change significantly.Comprehensive analysis shows that the optimal ratio is 4 mass% for Al powder or Si powder;(3)Al₂O₃ and SiO₂ are generated after oxidation of Al/Si powder,which react with periclase and calcium silicate in the material to form magnesium aluminate spinel,merwinite (magnesite pyroxene),monticellite,etc.,densifying the materials and enhancing the oxidation resistance.

Key words: aluminum powder, silicon powder, stabilized magnesia dolomite, oxidation resistance

摘要：

为提高耐火材料资源的综合利用率,以自制的稳定镁白云石合成料、电熔镁砂、Al粉、Si粉和鳞片石墨为原料,制备了Al粉、Si粉复合低碳稳定镁钙试样,研究了Al粉和Si粉复合低碳稳定镁钙材料的抗氧化性能,并探究了材料的抗氧化性能与物相组成和显微结构之间的关系。结果表明:1)加入金属Al粉和Si粉的抗氧化机制表现为明显的保护性氧化。2)1 000和1 500 ℃各氧化3 h后,未加入Al粉、Si粉的试样完全氧化。含Al粉、Si粉的试样氧化层厚度减小,抗氧化性提高。加入Al粉可有效地提高材料的抗氧化性,Al粉的最适宜加入量为4%(w),仅加入Si粉的试样氧化层厚度变化不明显。综合分析,最优配比为Al粉与Si粉均加入4%(w)。3)Al粉、Si粉氧化后分别生成的Al₂O₃和SiO₂,与材料中的方镁石和硅酸钙反应生成镁铝尖晶石、镁硅钙石(镁蔷薇辉石)和钙镁橄榄石等物相,使材料的内部结构更加致密,提高了材料的抗氧化性能。

关键词: Al粉, Si粉, 稳定镁白云石, 抗氧化性

CLC Number:

TQ175

Gao Zhengxia, Tao Mengya, Liu Wei, Meng Wei, Ma Chengliang, Zhong Xiangchong. Oxidation resistance of Al/Si composite low-carbon stabilized MgO-CaO materials[J]. Refractories, 2021, 55(5): 430-434.

高正霞, 陶梦雅, 刘伟, 孟维, 马成良, 钟香崇. Al粉、Si粉复合低碳稳定镁钙材料的抗氧化性[J]. 耐火材料, 2021, 55(5): 430-434.

Figures/Tables 9

Table 1 Chemical composition and physical properties of starting materials

原料	w/%
原料	MgO	CaO	SiO₂	Al₂O₃	Fe₂O₃
稳定镁白云石合成料	54.57	30.63	12.51	1.37	0.92
电熔镁砂	97.71	0.92	0.46	0.32	0.57

Table 2 Formulations of specimens

原料		w/%
原料		A0S0	A4S0	A4S2	A4S4	A4S6	A0S4	A2S4	A6S4
稳定镁白云石合成料	5~3 mm	18	18	18	18	18	18	18	18
	3~1 mm	32	32	32	32	32	32	32	32
	≤1 mm	12	12	12	12	12	12	12	12
电熔镁砂(<0.088 mm)		36	32	30	28	26	32	30	26
Al 粉		0	4	4	4	4	0	2	6
Si 粉		0	0	2	4	6	4	4	4
鳞片石墨		2	2	2	2	2	2	2	2
酚醛树脂(外加)		4	4	4	4	4	4	4	4

Fig.1 Thickness of oxidized layers after treating at 1 000 ℃ and 1 500 ℃

Fig.2 Change curve of mass change rate of specimen with heat treatment temperature

Fig.3 Mass change rate of specimens treated at 1 500 ℃

Fig.4 Phase composition of oxidized layer of specimen A4S0

Fig.5 Microphotographs of specimen A4S0 surface after oxidation

Fig.6 SEM photographs of oxidized layer and intermediate layer of specimen A4S0

Fig.7 SEM photographs of oxidized layer of specimens with different additions of Al powder

References 16

[1]	艾丽, 涂军波. 锆刚玉对不烧铝碳滑板强度和抗氧化性能的影响[J]. 河北联合大学学报(自然科学版), 2016, 38(2):105-110.
[2]	代黎明, 肖国庆, 丁冬海. 含碳耐火材料防氧化技术综述[J]. 材料导报, 2021, 35(3):3057-3066.
[3]	DEO B. Wear and dissolution of MgO-C refractory lining in belly and top cone regions of BOF vessel[J]. Transactions of the Indian Institute of Metals, 2017, 70(8):1965-1971. DOI URL
[4]	陈勇强, 李红霞, 刘国齐. 层状陶瓷及层状耐火材料研究进展[J]. 材料导报, 2019, 33(17):2847-2853.
[5]	李勇, 闫明伟, 秦海霞, 等. 非氧化物复合耐火材料的应用研究进展[J]. 硅酸盐学报, 2017, 45(9):1231-1239.
[6]	李新健, 柯昌明, 李楠. 含碳耐火材料的防氧化方法[J]. 耐火材料, 2006, 50(2):133-135+142.
[7]	赵臣瑞, 孙洋, 牛智旺, 等. 升温制度对Al-MgO-Al₂O₃耐火材料物相组成及显微结构的影响[J]. 耐火材料, 2021, 55(2):107-110.
[8]	任桢, 马成良, 钟香崇. 加入Al粉Si粉对低碳MgO-Al₂O₃-C材料性能的影响[J]. 耐火材料, 2010, 44(1):38-40.
[9]	韩彦锋, 赵臣瑞, 牛智旺, 等. 铝硅合金对不烧铝碳滑板性能的影响[C]// 2021年全国耐火原料学术交流会论文集,重庆, 2021: 4.
[10]	孙铭成, 马成良, 钟香崇. Al粉加入量对树脂结合MgO-CaO材料性能的影响[J]. 耐火材料, 2010, 58(6):423-425.
[11]	李文凤, 李素平, 钟香崇. 金属在耐火材料中的应用研究进展[J]. 耐火材料, 2015, 49(1):77-80.
[12]	李红霞. 耐火材料发展概述[J]. 无机材料学报, 2018, 33(2):198-205.
[13]	童则明, 李伟, 李彦明. 硅粉对金属Al结合镁铝碳滑板材料性能的影响[J]. 硅酸盐通报, 2020, 39(7):2297-2301.
[14]	孟维, 马成良, 钟香崇. 烧成温度对稳定性镁白云石材料性能的影响[J]. 耐火材料, 2016, 50(3):174-176.
[15]	孟维, 马成良, 葛铁柱, 等. 稳定性锆镁白云石合成材料的制备、结构和性能研究[J]. 郑州大学学报(工学版), 2016, 37(4):40-43.
[16]	LIU Z Y, YU J K, YUE S J, et al. Effect of carbon content on the oxidation resistance and kinetics of MgO-C refractory with the addition of Al powder[J]. Ceramics International, 2020, 46(3):3091-3098. DOI URL