ZrO_2/Al_2O_3系层状复合陶瓷材料的研究
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摘要
拟自然界贝壳的结构设计出的一种仿生结构强韧化的材料?层状复合陶瓷独特的叠层结构,使得研究者能从宏观结构的角度进行层内和层间的设计,从而制得综合性能优越的新型材料?本文从多层复合陶瓷的设计思路和工程应用要求出发,并综合考虑了ZTA及PSZ型材料的相变增韧?热膨胀失配,颗粒弥散增韧等协同增韧的机制,设计了表面薄层(主要成分为30wt%Al2O3 + ZrO2和45wt%Al2O3+ZrO2),中间厚层(主要成分为5wt%Al2O3+ZrO2)的三层结构复合陶瓷,表面层厚度在300~500(m范围内?通过扫描电子显微镜,力学性能测验等实验设备和手段,系统研究了ZrO2/Al2O3层状复合陶瓷工艺,层状结构形貌及断口形貌,性能及其之间的关系?
本研究在无压烧结的条件下,通过调整表面层配方及降低升温速率等方法,在1650℃×1h烧结,获得相对密度达98%以上的层状复合陶瓷制品?其中:表面组成45%wtAl2O3+ZrO2的层状陶瓷抗弯强度为682MPa,硬度为15.5Gp,断裂韧性8.26Mpa.m1/2,较单层陶瓷提高30%~50%?同时,通过研究发现,成型压力及加压方式的改变将直接影响生胚密度和制品的致密度?
本研究中选择选取成型压力在250~300Mpa,双面加压方式,获得了致密的层状复合陶瓷?测热震稳定性的实验表明层状复合陶瓷临界热震温差≥450℃,高出单层陶瓷200℃左右?将38×6.5×5mm的层状复合陶瓷,进行热模拟工况条件的实验表明,该层状复合陶瓷显示一定的优越性能,可望在高温热冲击的恶劣条件下应用?
SEM观察结果表明,该层状复合陶瓷在层间的结合是一种波浪型界面,ZrO2和Al2O3的颗粒结合紧密,Al2O3颗粒含量在层间界面处有着明显的过渡梯度,由于ZrO2的相变及热失配的作用引发了一定量的微裂纹,同时由于表面压应力的存在及Al2O3颗粒的弥散作用细化了晶粒,在这些机制协同的作用下,ZrO2/Al2O3层状复合陶瓷韧性得到了很大的提高?
对单层陶瓷及层状复合陶瓷的热震稳定性分析表明,引入热震阻力参数KR,作出相应的热震阻力曲线,经研究发现,单层陶瓷(成分组成为5wt%Al2O3+ZrO2),层状复合陶瓷(中间层组成为5wt%Al2O3+ZrO2,表面组成为30wt%Al2O3+ZrO2,45Wt%Al2O3+ZrO2)均表现出上升的阻力曲线行为及耐缺陷的性能?表面组成为45wt%Al2O3+ZrO2的层状陶瓷的热震稳定性比单层陶瓷高约50%??
Laminated ceramics is a kind of obdurability material, which is imitative of the framework of shell in the nature. The special superposition of the laminated ceramics make the researcher can proceed designing inside the layer and among layers from the macro-aspect, and synthesize the new material with the superiority performance. Based on the design ways of multi-layered ceramics and the advisement of the effect of transformation-toughened, thermal-mismatched, dispersion-toughened of particle of ZTA and PSZ, the paper produced a three-layer ZrO2/Al2O3 ceramics-30wt%Al2O3 + ZrO2 or 45wt%Al2O3 + ZrO2 in the two surfaces, 5wt%Al2O3 + ZrO2 in the center. The surface thickness is approximately 300~500. Through scan electronic microscopy and mechanical property instruments, the relationship of the process, microstructure and mechanical property of the three-layer ZrO2/Al2O3 ceramics was systematically studied.
In this research , we used non-pressure sintering process, adjusted the surface compositions and lowered the heating rate, and finally obtained >98% relative density in the condition of 1650℃×1h. The product of 45wt%Al2O3 + ZrO2 surface composition has high mechanical properties: 682 Mpa bending strength, 15.5Gpa hardness,8.26Mpa.m1/2 fracture toughness, higher 30%~50% than those of mono-layer ceramics. Meanwhile, further study showed that molding-pressure and the method of pressing will directly affect the density of embryo products and products.
In this paper, we obtain the dense products by the two-direction pressing and at the pressure of 250~300Mpa. The result of experimentation of thermal-shock showed that the critical temperature difference of the three-layer ZrO2/Al2O3 ceramics was above 450℃,higher 200℃ than those of monothic ceramics. The 38×6.5×5mm laminated ceramics revealed superiority performance to the extend in the experimentation of thermal simulation.
The result of SEM reveals that the laminar ceramics is a kind of wave interface structure, the particles of ZrO2 and Al2O3 combine densely. At the effect of transformation-toughened, thermal-mismatched, dispersion-toughed of particle etc., the toughness of the laminar ceramics improves greatly.
The analysis of thermal shock stability of the monothic ceramics and laminar ceramics showed that the monothic ceramics of 5wt%Al2O3 + ZrO2 and the laminar ceramics (30wt%Al2O3 + ZrO2 or 45wt%Al2O3 + ZrO2 in the two surfaces) revealed the ascend resistance-curve and the performance of flaw-tolerate. The thermal shock
stability of laminar ceramics of 45wt%Al2O3 + ZrO2 in the two surface is higher approximately 50% than those of monothic ceramics.
本研究在无压烧结的条件下,通过调整表面层配方及降低升温速率等方法,在1650℃×1h烧结,获得相对密度达98%以上的层状复合陶瓷制品?其中:表面组成45%wtAl2O3+ZrO2的层状陶瓷抗弯强度为682MPa,硬度为15.5Gp,断裂韧性8.26Mpa.m1/2,较单层陶瓷提高30%~50%?同时,通过研究发现,成型压力及加压方式的改变将直接影响生胚密度和制品的致密度?
本研究中选择选取成型压力在250~300Mpa,双面加压方式,获得了致密的层状复合陶瓷?测热震稳定性的实验表明层状复合陶瓷临界热震温差≥450℃,高出单层陶瓷200℃左右?将38×6.5×5mm的层状复合陶瓷,进行热模拟工况条件的实验表明,该层状复合陶瓷显示一定的优越性能,可望在高温热冲击的恶劣条件下应用?
SEM观察结果表明,该层状复合陶瓷在层间的结合是一种波浪型界面,ZrO2和Al2O3的颗粒结合紧密,Al2O3颗粒含量在层间界面处有着明显的过渡梯度,由于ZrO2的相变及热失配的作用引发了一定量的微裂纹,同时由于表面压应力的存在及Al2O3颗粒的弥散作用细化了晶粒,在这些机制协同的作用下,ZrO2/Al2O3层状复合陶瓷韧性得到了很大的提高?
对单层陶瓷及层状复合陶瓷的热震稳定性分析表明,引入热震阻力参数KR,作出相应的热震阻力曲线,经研究发现,单层陶瓷(成分组成为5wt%Al2O3+ZrO2),层状复合陶瓷(中间层组成为5wt%Al2O3+ZrO2,表面组成为30wt%Al2O3+ZrO2,45Wt%Al2O3+ZrO2)均表现出上升的阻力曲线行为及耐缺陷的性能?表面组成为45wt%Al2O3+ZrO2的层状陶瓷的热震稳定性比单层陶瓷高约50%??
Laminated ceramics is a kind of obdurability material, which is imitative of the framework of shell in the nature. The special superposition of the laminated ceramics make the researcher can proceed designing inside the layer and among layers from the macro-aspect, and synthesize the new material with the superiority performance. Based on the design ways of multi-layered ceramics and the advisement of the effect of transformation-toughened, thermal-mismatched, dispersion-toughened of particle of ZTA and PSZ, the paper produced a three-layer ZrO2/Al2O3 ceramics-30wt%Al2O3 + ZrO2 or 45wt%Al2O3 + ZrO2 in the two surfaces, 5wt%Al2O3 + ZrO2 in the center. The surface thickness is approximately 300~500. Through scan electronic microscopy and mechanical property instruments, the relationship of the process, microstructure and mechanical property of the three-layer ZrO2/Al2O3 ceramics was systematically studied.
In this research , we used non-pressure sintering process, adjusted the surface compositions and lowered the heating rate, and finally obtained >98% relative density in the condition of 1650℃×1h. The product of 45wt%Al2O3 + ZrO2 surface composition has high mechanical properties: 682 Mpa bending strength, 15.5Gpa hardness,8.26Mpa.m1/2 fracture toughness, higher 30%~50% than those of mono-layer ceramics. Meanwhile, further study showed that molding-pressure and the method of pressing will directly affect the density of embryo products and products.
In this paper, we obtain the dense products by the two-direction pressing and at the pressure of 250~300Mpa. The result of experimentation of thermal-shock showed that the critical temperature difference of the three-layer ZrO2/Al2O3 ceramics was above 450℃,higher 200℃ than those of monothic ceramics. The 38×6.5×5mm laminated ceramics revealed superiority performance to the extend in the experimentation of thermal simulation.
The result of SEM reveals that the laminar ceramics is a kind of wave interface structure, the particles of ZrO2 and Al2O3 combine densely. At the effect of transformation-toughened, thermal-mismatched, dispersion-toughed of particle etc., the toughness of the laminar ceramics improves greatly.
The analysis of thermal shock stability of the monothic ceramics and laminar ceramics showed that the monothic ceramics of 5wt%Al2O3 + ZrO2 and the laminar ceramics (30wt%Al2O3 + ZrO2 or 45wt%Al2O3 + ZrO2 in the two surfaces) revealed the ascend resistance-curve and the performance of flaw-tolerate. The thermal shock
stability of laminar ceramics of 45wt%Al2O3 + ZrO2 in the two surface is higher approximately 50% than those of monothic ceramics.
引文
[1] 师昌绪等,《陶瓷材料》--材料科学与技术丛书
[2] 李世普 ,《特种陶瓷工艺学》,武汉工业大学出版社,1990年
[3] Steinbrech R.W. Toughening mechanisms for ceramic materials. Journal of the European Ceram.Soc. ,1992,10(3):131-142
[4] Becher P. F. Microstructural design of toughened ceramics. J.Am.Ceramic.Soc. , 1991,74(2)255-269
[5] Levitt S.R. High-strength graphite fiber/lithium aluminosilicate composites. J.Mater.Sci. , 1973,8(6) : 793-806
[6] Fitzer E, Gadow R. Fiber-reinforced silicon carbide. Am.Ceram.Soc.Bull. ,1986,65(2):326-335
[7] Schwartz M M ed. Handbook of structural ceramics. NewYork : McGraw-Hill,Ind. ,1992
[8] 周洋等 ,高温结构陶瓷基复合材料的研究现状与展望,《硅酸盐通报》,2001.4
[9] Clegg W J, Kendall K,Alford N M. A simple way to make tough ceramics. Nature ,1990,347(10):445-447
[10] Culter W A, Zok F W ,Language F F. Mechanical behavior of several hybrid ceramic-matrix-composite laminates. J.Am.Ceram.Soc. ,1996,79(7):1825-1833
[11] 向春霆,范镜泓, 自然复合材料的强韧化机理和仿生复合材料的研究,《力学进展》,1995,24(2):220-231
[12] Clegg W J. The fabrication and failure of laminar ceramic composites. Acta Metall.Mater. ,1992,40 (11):3085-3093
[13] Liu H,Hsu S M. Fracture behavior of multiplayer silicon nitride/boron nitride ceramics. J.Am.Ceram.Soc. , 1996,79(9):2452-2457
[14] Kovar D, Thouless M D,Halloran J W .Crack deflection and propagation in layered silicon nitride/boron nitride ceramics. J.Am.Ceram.Soc. ,1998(4):1004-1012
[15] Danko G A ,Hilamas G E ,Halloran J W, et al. Fabrication and properties of quasi-isotropic silicon nitride-boron nitride fibrous monoliths .Ceram.Eng.&Sci.Proc., 1997,18(3):607-613
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[18] Clegg W J.Design of ceramic laminates for structural applications. Mater.Sci.Tech. , 1998,14:483-495
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[23] 王杰曾,金宗哲等,耐火材料抗热震疲劳行为评价的研究,《硅酸盐学报》2000.2
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[25] 陈加庚,陶瓷材料抗热震断裂性和抗热震损伤性的统一理论,中国陶瓷,1995,vol31(5) p31-34
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[29] D.P.H.Hasselman,E.P.Chen,and P.A.Urick, Prediction of the thermal Fatigue Resistance of Indented Glass Rods, Am.Ceram.Soc.Bull., 1978,vol57(2)p190-192
[30] J.H.Gong ,Z.D.Guan,and D.C.Jiang. Analysis for strength degradation of idented Specimens due to thermal shock , Fracture Mechanics of Ceramics,1992,vol10 p605-610
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[32] K.T.Faber,M.D.Huang, and A.G.Evans ,Quantitative studies of thermal shock in ceramics based on a novel test technique, J.Am Ceram.Soc .,1981,vol64(5)p296-301
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[36] 关振铎,李淑琴等, Si3N4-TiN/BN层状陶瓷材料阻力曲线及其增韧机制的研究,《硅酸盐学报》2001.2
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[2] 李世普 ,《特种陶瓷工艺学》,武汉工业大学出版社,1990年
[3] Steinbrech R.W. Toughening mechanisms for ceramic materials. Journal of the European Ceram.Soc. ,1992,10(3):131-142
[4] Becher P. F. Microstructural design of toughened ceramics. J.Am.Ceramic.Soc. , 1991,74(2)255-269
[5] Levitt S.R. High-strength graphite fiber/lithium aluminosilicate composites. J.Mater.Sci. , 1973,8(6) : 793-806
[6] Fitzer E, Gadow R. Fiber-reinforced silicon carbide. Am.Ceram.Soc.Bull. ,1986,65(2):326-335
[7] Schwartz M M ed. Handbook of structural ceramics. NewYork : McGraw-Hill,Ind. ,1992
[8] 周洋等 ,高温结构陶瓷基复合材料的研究现状与展望,《硅酸盐通报》,2001.4
[9] Clegg W J, Kendall K,Alford N M. A simple way to make tough ceramics. Nature ,1990,347(10):445-447
[10] Culter W A, Zok F W ,Language F F. Mechanical behavior of several hybrid ceramic-matrix-composite laminates. J.Am.Ceram.Soc. ,1996,79(7):1825-1833
[11] 向春霆,范镜泓, 自然复合材料的强韧化机理和仿生复合材料的研究,《力学进展》,1995,24(2):220-231
[12] Clegg W J. The fabrication and failure of laminar ceramic composites. Acta Metall.Mater. ,1992,40 (11):3085-3093
[13] Liu H,Hsu S M. Fracture behavior of multiplayer silicon nitride/boron nitride ceramics. J.Am.Ceram.Soc. , 1996,79(9):2452-2457
[14] Kovar D, Thouless M D,Halloran J W .Crack deflection and propagation in layered silicon nitride/boron nitride ceramics. J.Am.Ceram.Soc. ,1998(4):1004-1012
[15] Danko G A ,Hilamas G E ,Halloran J W, et al. Fabrication and properties of quasi-isotropic silicon nitride-boron nitride fibrous monoliths .Ceram.Eng.&Sci.Proc., 1997,18(3):607-613
[16] Huang Y, Hao H N ,Chen Y L ,et al. Design and preparation of silicon nitride compisite with high fracture toughness and nace structure. Acta.Metall.Sinica,1996,9(6):479-484
[17] Chartier T, Merle D, Besson J L. Laminar ceramic composites. J.Euro.Ceram.Soc., 1995,15:101-107
[18] Clegg W J.Design of ceramic laminates for structural applications. Mater.Sci.Tech. , 1998,14:483-495
[19] 杨辉,葛曼珍等,《材料加工和研究进展》,第二卷,化工出版社,1996.5:236
[20] 钱小倩,葛曼珍等,层状复合陶瓷强韧化机制及其优化设计因素,《无机材料学报》 1999.8
[21] 邱关明,《新型陶瓷》,兵器工业出版社,1989
[22] 施剑林,李包顺,3Y-TZP 多晶材料密度?断裂相变?与力学性能的相互关系,材料研究学报,1996,vol10(1)p51-53
[23] 王杰曾,金宗哲等,耐火材料抗热震疲劳行为评价的研究,《硅酸盐学报》2000.2
[24] 工程陶瓷抗热震性实验方法,GB/T 16536-1996
[25] 陈加庚,陶瓷材料抗热震断裂性和抗热震损伤性的统一理论,中国陶瓷,1995,vol31(5) p31-34
[26] 王杰曾,金宗哲等,耐火材料力学-热物理性能的评述,硅酸盐通报,1996.1 p41-45
[27] Beach P.F., Transient Thermal Stress in ZrO2-toughened Al2O3, J.Am.Ceram. Soc., 1981,vol164(1)p37-39
[28] Tomas Andersson, David J.Rowcliffe, Indentation Thermal Shock Test for Ceramics, J.Am.Ceram.Soc., 1996,vol79(6)p1509-1512
[29] D.P.H.Hasselman,E.P.Chen,and P.A.Urick, Prediction of the thermal Fatigue Resistance of Indented Glass Rods, Am.Ceram.Soc.Bull., 1978,vol57(2)p190-192
[30] J.H.Gong ,Z.D.Guan,and D.C.Jiang. Analysis for strength degradation of idented Specimens due to thermal shock , Fracture Mechanics of Ceramics,1992,vol10 p605-610
[31] F.Osterstock, Contact damage submitted to thermal shock:a method to evaluate and simulate thermal shock resistance to brittle materials, Mater.Sci.Eng.,1993,A 168,p41-44
[32] K.T.Faber,M.D.Huang, and A.G.Evans ,Quantitative studies of thermal shock in ceramics based on a novel test technique, J.Am Ceram.Soc .,1981,vol64(5)p296-301
[33] 赵世柯等,ZrO2 相变设计改善耐火材料抗热震性的设想,耐火材料,1999,33(2)p104-106
[34] Olagnon C et al., Thermal shock and Thermal Fatigue Bahaviour of Advanced Ceramics. , NATO ASI Series,1993,p371-382
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