纳米钛酸钡前体热分解反应动力学及颗粒演化机理

doi:10.16085/j.issn.1000-6613.2024-0069

摘要/Abstract

摘要：

钛酸钡具有介电常数高、介电损耗低等优良性能，是制备多层陶瓷电容器等元件的基础原料。以草酸盐共沉淀法制备的纳米钛酸钡前体为原料，采用热重-质谱联用分析仪研究了其热分解特性和气体析出特性，揭示了纳米钛酸钡前体热分解反应的机理，利用kissinger-akahira-sunose（KAS）法和flynn-wall-ozawa（FWO）法进行了反应动力学计算，并采用扫描电子显微镜（SEM）观察了热分解产物的微观形貌，分析了颗粒的演化机理。结果显示：纳米钛酸钡前体热分解过程可分为4个失重阶段，第一阶段为水分析出，第二阶段的析出气体为CO和CO₂，第三和第四阶段的析出气体为CO₂，据此推导出了各阶段涉及的反应式；随着升温速率的提高，各失重阶段对应的最大失重速率温度均向高温区移动，第四阶段向高温区移动的幅度最大，达到113℃，但该阶段在30℃/min条件下的失重速率最快、反应得到强化；FWO模型更适用于描述纳米钛酸钡前体的热分解过程，四个阶段的平均反应活化能分别为67.89kJ/mol、208.92kJ/mol、494.04kJ/mol和195.11kJ/mol，第三阶段的反应活化能最高、反应较难发生；在纳米钛酸钡前体热分解过程中，宏观大颗粒会演化成微观小颗粒的聚集体，较高的恒温温度会导致颗粒粒径变大，因此恒温温度不宜超过900℃。研究结果为纳米钛酸钡前体热分解工艺参数的选择提供了理论依据。

关键词: 钛酸钡前体, 热分解, 动力学, 热重-质谱, 颗粒演化

Abstract:

Barium titanate has excellent properties such as high dielectric constant and low dielectric loss, and is the main raw material for preparing multilayer ceramic capacitors and other components. The thermal decomposition and gas precipitation characteristics of nano barium titanate precursor prepared by oxalate co-precipitation method were studied using a thermogravimetric-mass spectrometry analyzer, and the mechanism of thermal decomposition reaction of nano barium titanate precursor was revealed. The kinetic calculations were carried out using kissinger-akahira-sunose (KAS) method and flynn-wall-ozawa (FWO) method. The microstructure of the thermal decomposition products was observed using scanning electron microscopy (SEM), and the evolution mechanism of particles was analyzed. The results showed that the thermal decomposition process of nano barium titanate precursor could be divided into four weight-loss stages. The first stage was the release of water, the second stage produced CO and CO₂, and the third and fourth stages produced CO₂. Based on these results, the reactions involved in each stage were derived. As the heating rate increased, the maximum weight loss rate temperature corresponding to each weight loss stage moved towards the high-temperature zone. The fourth stage had the largest displacement towards the high-temperature zone, reaching 113℃. However, this stage had the fastest weight-loss rate and the reactions had been strengthened under the condition of 30℃/min. The FWO model was more suitable for describing the thermal decomposition process of nano barium titanate precursors. The average activation energies of the four stages were 67.89 kJ/mol, 208.92 kJ/mol, 494.04 kJ/mol and 195.11 kJ/mol, respectively. The activation energy of the third stage was the highest and the reaction was difficult to occur. During the thermal decomposition process of nano barium titanate, macroscopic large particles would evolve into aggregates of microscopic small particles. A higher constant temperature would lead to an increase in particle size. Therefore, the recommended constant temperature should not exceed 900℃. This research provided a theoretical basis for the selection of thermal decomposition process parameters for nano barium titanate precursors.

Key words: barium titanate precursor, thermal decomposition, dynamics, thermogravimetric-mass spectrometry, particle evolution

中图分类号:

TQ174

张昊, 陆小明. 纳米钛酸钡前体热分解反应动力学及颗粒演化机理[J]. 化工进展, 2024, 43(7): 3987-3995.

ZHANG Hao, LU Xiaoming. Thermal decomposition kinetics and particle evolution characteristics of nano barium titanate precursor[J]. Chemical Industry and Engineering Progress, 2024, 43(7): 3987-3995.

图/表 11

图1 程序升温至1000℃的TG-DTG曲线

图2 气体析出特性曲线

表1 钛酸钡前体热分解反应参数及机理

阶段	温度/℃	失重率/%	热分解过程涉及的反应	编号
第一阶段	20~190	11	$B a T i O C 2 O 4 2 · 4 H 2 O → B a T i O C 2 O 4 2 + 4 H 2 O$ ↑	式(5)
第二阶段	190~410	20	$2 B a T i O C 2 O 4 2 → B a 2 T i 2 O 5 C 2 O 5 + 4 C O ↑ + 2 C O 2$ ↑	式(6)
第三阶段	410~640	5	$B a 2 T i 2 O 5 C 2 O 5 → C O 2$ ↑ $+ B a C O 3 + 2 T i O 2 + B a O$	式(7)
第四阶段	640~720	7	$B a O + T i O 2 → B a T i O 3$ $B a C O 3 + T i O 2 → B a T i O 3 + C O 2 ↑$	式(8) 式(9)
第五阶段	720~1000	0	—	—

表1 钛酸钡前体热分解反应参数及机理

阶段	温度/℃	失重率/%	热分解过程涉及的反应	编号
第一阶段	20~190	11	$B a T i O C 2 O 4 2 · 4 H 2 O → B a T i O C 2 O 4 2 + 4 H 2 O$ ↑	式(5)
第二阶段	190~410	20	$2 B a T i O C 2 O 4 2 → B a 2 T i 2 O 5 C 2 O 5 + 4 C O ↑ + 2 C O 2$ ↑	式(6)
第三阶段	410~640	5	$B a 2 T i 2 O 5 C 2 O 5 → C O 2$ ↑ $+ B a C O 3 + 2 T i O 2 + B a O$	式(7)
第四阶段	640~720	7	$B a O + T i O 2 → B a T i O 3$ $B a C O 3 + T i O 2 → B a T i O 3 + C O 2 ↑$	式(8) 式(9)
第五阶段	720~1000	0	—	—

图3 不同升温速率下的TG曲线

图4 不同升温速率条件下的DTG曲线

表2 不同升温速率条件下各失重阶段达到一定转化率对应的温度

阶段	升温速率 /℃·min^-1	温度/℃
阶段	升温速率 /℃·min^-1	α_10%	α_20%	α_40%	α_60%	α_80%	α_90%
第一阶段	2	44	61	74	85	106	129
	5	54	72	88	99	117	138
	10	60	81	98	111	133	156
	20	72	95	113	125	148	174
	30	73	100	121	134	156	180
第二阶段	2	288	306	326	340	358	377
	5	300	318	337	351	370	388
	10	310	327	345	360	380	398
	20	322	338	356	372	394	413
	30	327	344	362	378	402	421
第三阶段	2	436	448	471	495	522	539
	5	446	457	479	505	534	552
	10	451	461	480	506	536	555
	20	464	472	489	513	543	566
	30	470	478	494	516	544	569
第四阶段	2	608	615	623	631	646	658
	5	632	641	652	664	681	688
	10	656	668	684	696	705	709
	20	685	703	717	722	727	731
	30	705	722	730	735	740	743

图5 KAS模型

图6 FWO模型

表3 动力学参数

阶段	转化率/%	FWO模型		KAS模型
阶段	转化率/%	E_a /kJ·mol^–1	R²	E_a /kJ·mol^–1	R²
第一阶段	10	76.86	0.985	75.29	0.982
	20	66.79	0.994	63.01	0.992
	40	62.43	0.997	59.55	0.994
	60	63.93	0.999	60.43	0.998
	80	67.03	0.99	64.41	0.986
	90	70.32	0.977	65.96	0.966
	平均	67.89	0.99	64.77	0.986
第二阶段	10	181.87	0.998	181.59	0.998
	20	201.5	0.999	206.17	0.995
	40	226.35	0.997	216.69	0.99
	60	222.68	0.996	216.3	0.99
	80	205.81	0.993	215.11	0.989
	90	215.3	0.987	215.33	0.986
	平均	208.92	0.995	208.53	0.991
第三阶段	10	327.39	0.978	332.19	0.977
	20	385.38	0.976	393.01	0.974
	40	531.34	0.962	546.17	0.963
	60	619.11	0.969	638.09	0.967
	80	615.75	0.961	634.09	0.969
	90	485.28	0.978	496.54	0.977
	平均	494.04	0.971	506.68	0.971
第四阶段	10	188.76	0.992	183.05	0.99
	20	173.01	0.992	166.29	0.99
	40	173.64	0.996	166.81	0.995
	60	183.85	0.996	177.45	0.996
	80	212.64	0.995	207.56	0.994
	90	238.78	0.998	234.91	0.998
	平均	195.11	0.995	189.35	0.994

图7 热重分析仪恒温温度对纳米钛酸钡微观形貌的影响

图8 纳米钛酸钡前体热分解过程的颗粒演化机理

参考文献 21

1	上官明楠, 王超莹, 赵昀云, 等. 四方相纳米钛酸钡粉体的制备及性能研究[J]. 绝缘材料, 2024, 57(2): 53-59.
	SHANGGUAN Mingnan, WANG Chaoying, ZHAO Yunyun, et al. Study on preparation and properties of tetragonal phase nano-barium titanate powder[J]. Insulating Materials, 2024, 57(2): 53-59.
2	赵虔诚. 抗还原型钛酸钡基储能陶瓷材料的研究[D]. 北京: 清华大学, 2018.
	ZHAO Qiancheng. Study on non-reducible Barium titanate based energy-storage ceramics[D]. Beijing: Tsinghua University, 2018.
3	VINCENZO Buscaglia, RANDALL CLIVE A. Size and scaling effects in Barium titanate. An overview[J]. Journal of the European Ceramic Society, 2020, 40(11): 3744-3758.
4	李雪梅. 固相法制备亚微米钛酸钡粉体的研究[D]. 重庆: 重庆理工大学, 2023.
	LI Xuemei. Study on preparation of submicron Barium titanate powder by solid state method[D]. Chongqing: Chongqing University of Technology, 2023.
5	周斌. 抗还原型钛酸钡基材料的制备与性能研究[D]. 南昌: 南昌大学, 2023.
	ZHOU Bin. Research on preparation and properties of non-reducible Barium titanate-based materials[D]. Nanchang: Nanchang University, 2023.
6	PANOMSUWAN Gasidit, MANUSPIYA Hathaikarn. Correlation between size and phase structure of crystalline BaTiO₃ particles synthesized by sol-gel method[J]. Materials Research Express, 2019, 6(6): 065062.
7	白罗. 水热合成四方相钛酸钡粉体及其形貌调控与分散性研究[D]. 武汉: 武汉理工大学, 2022.
	BAI Luo. Study on morphology regulation and dispersion of tetragonal phase Barium titanate powder by hydrothermal synthesis[D]. Wuhan: Wuhan University of Technology, 2022.
8	邵志鹏, 江伟辉, 冯果, 等. 沉淀法和NHSG法制备钛酸钡纳米粉体的对比研究[J]. 陶瓷学报, 2016, 37(1): 44-48.
	SHAO Zhipeng, JIANG Weihui, FENG Guo, et al. Comparative study on the preparation of BatiO₃ nano powder via precipitation method and NHSG method[J]. Journal of Ceramics, 2016, 37(1): 44-48.
9	徐阳, 包莹. 化学沉淀法制备微细粉体钛酸钡的研究[J]. 兰州工业学院学报, 2017, 24(6): 86-89.
	XU Yang, BAO Ying. Preparation of ultrafine Barium titanate by chemical precipitation method[J]. Journal of Lanzhou Institute of Technology, 2017, 24(6): 86-89.
10	CHEN Huei-Jyh, CHEN Yuwen. Hydrothermal synthesis of Barium titanate[J]. Industrial & Engineering Chemistry Research, 2003, 42(3): 473-483.
11	Sung-Soo RYU, YOON Dang-Hyok. Solid-state synthesis of nano-sized BaTiO₃ powder with high tetragonality[J]. Journal of Materials Science, 2007, 42(17): 7093-7099.
12	杨雅文. 溶胶-凝胶法制备钛酸钡纳米粉体[J]. 山西化工, 2024, 44(1): 42-43, 46.
	YANG Yawen. Preparation of Barium titanate nanoparticles by sol-gel method[J]. Shanxi Chemical Industry, 2024, 44(1): 42-43, 46.
13	陈杰, 张晴, 车明超. 微波辅助草酸盐沉淀法制备四方相钛酸钡纳米粉体[J]. 人工晶体学报, 2017, 46(8): 1545-1551.
	CHEN Jie, ZHANG Qing, CHE Mingchao. Preparation of tetragonal Barium titanate nanopowders by oxalate co-precipitation assisted with microwave method[J]. Journal of Synthetic Crystals, 2017, 46(8): 1545-1551.
14	FRIEDMAN Henry L. Kinetics of thermal degradation of char-forming plastics from thermogravimetry. Application to a phenolic plastic[J]. Journal of Polymer Science Part C: Polymer Symposia, 1964, 6(1): 183-195.
15	SINGH Sanjay, PATIL Trilok, TEKADE Shyam P, et al. Studies on individual pyrolysis and co-pyrolysis of corn cob and polyethylene: Thermal degradation behavior, possible synergism, kinetics, and thermodynamic analysis[J]. Science of the Total Environment, 2021, 783: 147004.
16	HU Jinghui, GONG Li, HE Jiyu, et al. Studies on multistep thermal decomposition behavior of polytriazole polyethylene oxide-tetrahydrofuran elastomer[J]. Polymers for Advanced Technologies, 2020, 31(4): 749-758.
17	VENKATESH M, RAVI P, TEWARI Surya P. Isoconversional kinetic analysis of decomposition of nitroimidazoles: Friedman method vs. Flynn-Wall-Ozawa method[J]. The Journal of Physical Chemistry A, 2013, 117(40): 10162-10169.
18	SINDHU N V, MURALEEDHARAN K. Kinetic study of the multistep thermal behaviour of Barium titanyl oxalate prepared via chemical precipitation method[J]. Journal of Thermal Analysis and Calorimetry, 2019, 136(3): 1295-1306.
19	XU Jianfei, TSUTAI Sakae, HAYASHI Shigeo, et al. Thermal decomposition process of Barium titanyl oxalate tetrahydrate[J]. Journal of the Ceramic Society of Japan, 1999, 107(1241): 27-30.
20	李改改, 姜鹏飞, 黄佳齐, 等. 富油煤热解过程动力学参数变化规律研究[J]. 煤炭技术, 2023, 42(10): 52-56.
	LI Gaigai, JIANG Pengfei, HUANG Jiaqi, et al. Study on change of kinetic parameters of tar-rich coal during pyrolysis[J]. Coal Technology, 2023, 42(10): 52-56.
21	刘晓林, 高礼杰, 付极文, 等. 热处理过程对纳米钛酸钡相变的影响研究[J]. 北京化工大学学报(自然科学版), 2004, 31(6): 13-17.
	LIU Xiaolin, GAO Lijie, FU Jiwen, et al. Effect of heat treatment on phase transition of Barium titanate[J]. Journal of Beijing University of Chemical Technology, 2004, 31(6): 13-17.

[1]	丁路, 王培尧, 孔令学, 白进, 于广锁, 李文, 王辅臣. 煤气化过程反应模型研究进展[J]. 化工进展, 2024, 43(7): 3593-3612.
[2]	曹景沛, 姚乃瑜, 庞新博, 赵小燕, 赵静平, 蔡士杰, 徐敏, 冯晓博, 伊凤娇. 煤热解研究进展及其发展历程[J]. 化工进展, 2024, 43(7): 3620-3636.
[3]	顾颂琦, 孙凡飞, 韦尧, 宋兴飞, 南兵, 李丽娜, 黄宇营. 时间分辨热化学原位XAFS方法[J]. 化工进展, 2024, 43(7): 3747-3755.
[4]	马栋, 解桂林, 田治华, 王勤辉, 张建国, 宋慧林, 钟晋. 流化床中煤气化细渣高温还原磷石膏过程[J]. 化工进展, 2024, 43(6): 3479-3491.
[5]	江安迪, 丁雪兴, 王世鹏, 丁俊华, 力宁. 超临界CO₂干气密封热动力学性能研究进展[J]. 化工进展, 2024, 43(5): 2354-2369.
[6]	黄淄博, 周文静, 魏进家. 基于ReaxFF MD模拟的低阶煤热解产物演化规律及反应机理[J]. 化工进展, 2024, 43(5): 2409-2419.
[7]	王德斌, 林梦雨, 杨雪, 董殿权. 锌掺杂型钛系铯离子筛的制备及其吸附性能[J]. 化工进展, 2024, 43(4): 1953-1961.
[8]	张鹏飞, 陈伟鹏, 肖卓楠, 吕青岗, 张顺风, 张子峰. 红砖掺杂改性白云鄂博铁精矿载氧体性能[J]. 化工进展, 2024, 43(4): 2226-2234.
[9]	祝妍妮, 王维, 孙闫晨昊, 魏岗, 张大为. 基于单液滴蒸发的离心喷雾干燥数值模拟[J]. 化工进展, 2024, 43(4): 1700-1710.
[10]	何发超, 刘海龙, 李昌烽, 王军锋. 非均匀电场对高黏流体中气泡分散特性的影响[J]. 化工进展, 2024, 43(4): 1774-1782.
[11]	周逸寰, 解强, 周红阳, 梁鼎成, 刘金昌. 基于分子模拟的多孔炭材料结构模型构建方法研究进展[J]. 化工进展, 2024, 43(3): 1535-1551.
[12]	董晓涵, 田月, 苏毅. 含钛高炉渣制备复合吸附剂及其铬吸附性能[J]. 化工进展, 2024, 43(3): 1552-1564.
[13]	黄梦, 孙志高, 徐文超, 张焕然, 杨扬. 内酯型槐糖脂促进HCFC-141b水合物生成[J]. 化工进展, 2024, 43(3): 1199-1205.
[14]	黄益平, 李婷, 郑龙云, 戚傲, 陈政霖, 史天昊, 张新宇, 郭凯, 胡猛, 倪泽雨, 刘辉, 夏苗, 主凯, 刘春江. 三级环流反应器中气液流动与传质规律[J]. 化工进展, 2023, 42(S1): 175-188.
[15]	顾永正, 张永生. HBr改性飞灰对Hg⁰的动态吸附及动力学模型[J]. 化工进展, 2023, 42(S1): 498-509.