Al_2O_3陶瓷注射成型研究
摘要
本文以质量分数95%的Al2O3,5%的CaO-Al2O3-SiO2的粉体为研究对象,系统研究了氧化铝注射成型所涉及的喂料制备、注射成型以及脱脂等工艺过程。
论文研究了适合注射成型的95氧化铝粉体和石蜡-聚烯烃粘结剂体系,并对粘结剂组元的相容性进行了判断。系统讨论了喂料的固相体积分数对注射成型坯体、烧结体力学性能的影响,结果表明:当固相体积分数为59vol%时,脱脂后的试样有比较明显的塌陷现象,烧结体的密度为3.58g/cm3,抗弯强度为250.37MPa。当固相体积分数为70vol%时,脱脂后试样完好,烧结体的密度为3.73g/cm3,抗弯强度为290.56MPa。系统讨论了粘结剂配方对氧化铝喂料成形性和流动性的影响,实验结果表明,粘结剂中相对石蜡含量的增加有助于提高喂料的均匀性,降低喂料的粘度。但由于粘结剂体系中起支撑作用的骨架高聚物含量降低,从而使成型出来的素坯强度会随之下降,并且会进一步影响到烧结后样品的致密度。优化后的实验所用的粘结剂体系配方为72wt%PW-8wt%PP-8wt%VAE- 8wt%DBP-4wt%SA。
论文研究了注射参数对成形坯体的影响,特别是对坯体质量影响较大的两个重要参数(注射温度和注射压力)进行了系统的研究,结果表明:当注射压力为50MPa时,坯体产生凹陷现象;当注射压力为100MPa时,坯体内部容易形成较大的残余应力和应力集中,烧结体出现弯曲的现象。因此在保证充模完整的情况下应尽量减小注射压力。当注射温度为120℃-100℃-100℃-100℃-70℃时,会导致喂料充模不满;当注射温度为180℃-150℃-150℃-150℃-70℃时,将导致喂料中低熔点有机物挥发严重,进而造成坯体结构不致密。在此基础上,确定了实验中采用的各注射参数值。
论文分析了粘结剂体系中主要粘结剂组元的TGA曲线,研究发现,这种多组元构成的粘结剂体系能够将脱脂缺陷减少到最小。根据热脱脂过程和喂料的DTA/TGA曲线,制定了合理的热脱脂升温制度,讨论了固相体积分数对极限升温速率的影响,结果表明:固相体积分数越高,极限升温速率越大,因此适当提高固相体积分数,可以极大的缩短脱脂时间。针对脱脂过程中易产生的缺陷进行了分析,并提出了相应的解决措施。
This thesis presents about injection molding of alumina powder. The processes involved feedstock preparation, injection molding and the followed debinding process. The major works were showed as bellow:
Alumina powder and wax-polyolefin that are suitable for injection molding were studied,and the compatibility of binder system was judged. The influences of the solid loading on mechanical properties of the green and sintered parts were researched, the result shows that when the solid volume fraction is 59vol%, the debinded parts are depression, the density of sintered parts is 3.58g/cm3, the bending strength is 250.37MPa; when the solid volume fraction is 70vol%, the debinded parts are intact, the density of sintered parts is 3.73g/cm3, the bending strength is 290.56MPa. The influences of the relative proportion of binders on the homogeneity and formability of alumina feedstock was systematically discussed, The result shows that the increase of wax amount in binders helps to improve its homogeneity and decrease its viscosity. However, the increase of wax amount leads to the decrease of the polymers which play the role of skeleton in the feedstock, and results in the the density and bend strength of the feedstock decrease. The compactability of sintered ceramic will also be affected with the wax amount increase. the proportion of binders is 72wt%PW-8wt%PP-8wt%VAE- 8wt%DBP-4wt%SA
The influences of injection press and injection temperature on qualities of green were discussed. the result shows that when the injection press is 50MPa,the green is depression, when the injection press is 100MPa,which easily led to residual stress and stress concentration in the green, thus, injection pressure should reduce when die is complete. when the injection temperature is 120℃-100℃-100℃-100℃-70℃, feedstock will be not complete die; when the injection temperature is 180℃-150℃-150℃-150℃-70℃, which result in the volatile of the organic of low melting in the feedstock, and then sintered structure is not compactability. On these basis, the parameters used in the experiment are fixed.
The TGA of binders are respectively analyzed, binder system which is builded up by multi-crew binder helps to reduce defects. The reasonable procedure of thermal debinding was designed according to DTA/TG.A and thermal debinding process. The influences of the solid volume fraction on the velocity of heating were studied, the velocity of heating increase with the solid volume fraction were increased. Therefore, appropriately increasing the solid volume fraction, the time of debinding can be shorten. The solution can be proposed according to defects that occur easily in debinding.
论文研究了适合注射成型的95氧化铝粉体和石蜡-聚烯烃粘结剂体系,并对粘结剂组元的相容性进行了判断。系统讨论了喂料的固相体积分数对注射成型坯体、烧结体力学性能的影响,结果表明:当固相体积分数为59vol%时,脱脂后的试样有比较明显的塌陷现象,烧结体的密度为3.58g/cm3,抗弯强度为250.37MPa。当固相体积分数为70vol%时,脱脂后试样完好,烧结体的密度为3.73g/cm3,抗弯强度为290.56MPa。系统讨论了粘结剂配方对氧化铝喂料成形性和流动性的影响,实验结果表明,粘结剂中相对石蜡含量的增加有助于提高喂料的均匀性,降低喂料的粘度。但由于粘结剂体系中起支撑作用的骨架高聚物含量降低,从而使成型出来的素坯强度会随之下降,并且会进一步影响到烧结后样品的致密度。优化后的实验所用的粘结剂体系配方为72wt%PW-8wt%PP-8wt%VAE- 8wt%DBP-4wt%SA。
论文研究了注射参数对成形坯体的影响,特别是对坯体质量影响较大的两个重要参数(注射温度和注射压力)进行了系统的研究,结果表明:当注射压力为50MPa时,坯体产生凹陷现象;当注射压力为100MPa时,坯体内部容易形成较大的残余应力和应力集中,烧结体出现弯曲的现象。因此在保证充模完整的情况下应尽量减小注射压力。当注射温度为120℃-100℃-100℃-100℃-70℃时,会导致喂料充模不满;当注射温度为180℃-150℃-150℃-150℃-70℃时,将导致喂料中低熔点有机物挥发严重,进而造成坯体结构不致密。在此基础上,确定了实验中采用的各注射参数值。
论文分析了粘结剂体系中主要粘结剂组元的TGA曲线,研究发现,这种多组元构成的粘结剂体系能够将脱脂缺陷减少到最小。根据热脱脂过程和喂料的DTA/TGA曲线,制定了合理的热脱脂升温制度,讨论了固相体积分数对极限升温速率的影响,结果表明:固相体积分数越高,极限升温速率越大,因此适当提高固相体积分数,可以极大的缩短脱脂时间。针对脱脂过程中易产生的缺陷进行了分析,并提出了相应的解决措施。
This thesis presents about injection molding of alumina powder. The processes involved feedstock preparation, injection molding and the followed debinding process. The major works were showed as bellow:
Alumina powder and wax-polyolefin that are suitable for injection molding were studied,and the compatibility of binder system was judged. The influences of the solid loading on mechanical properties of the green and sintered parts were researched, the result shows that when the solid volume fraction is 59vol%, the debinded parts are depression, the density of sintered parts is 3.58g/cm3, the bending strength is 250.37MPa; when the solid volume fraction is 70vol%, the debinded parts are intact, the density of sintered parts is 3.73g/cm3, the bending strength is 290.56MPa. The influences of the relative proportion of binders on the homogeneity and formability of alumina feedstock was systematically discussed, The result shows that the increase of wax amount in binders helps to improve its homogeneity and decrease its viscosity. However, the increase of wax amount leads to the decrease of the polymers which play the role of skeleton in the feedstock, and results in the the density and bend strength of the feedstock decrease. The compactability of sintered ceramic will also be affected with the wax amount increase. the proportion of binders is 72wt%PW-8wt%PP-8wt%VAE- 8wt%DBP-4wt%SA
The influences of injection press and injection temperature on qualities of green were discussed. the result shows that when the injection press is 50MPa,the green is depression, when the injection press is 100MPa,which easily led to residual stress and stress concentration in the green, thus, injection pressure should reduce when die is complete. when the injection temperature is 120℃-100℃-100℃-100℃-70℃, feedstock will be not complete die; when the injection temperature is 180℃-150℃-150℃-150℃-70℃, which result in the volatile of the organic of low melting in the feedstock, and then sintered structure is not compactability. On these basis, the parameters used in the experiment are fixed.
The TGA of binders are respectively analyzed, binder system which is builded up by multi-crew binder helps to reduce defects. The reasonable procedure of thermal debinding was designed according to DTA/TG.A and thermal debinding process. The influences of the solid volume fraction on the velocity of heating were studied, the velocity of heating increase with the solid volume fraction were increased. Therefore, appropriately increasing the solid volume fraction, the time of debinding can be shorten. The solution can be proposed according to defects that occur easily in debinding.
引文
[1]梁叔全,黄伯云,粉末注射成型流变学,湖南:中南大学出版社,2000,1
[2]Song J H,Evans J R,The injection molding of fine and ultra-fine zirconia powders,Ceram.Int.1995,21:325-333
[3]颜鲁婷,司文捷,苗赫濯,CIM中最新脱脂工艺的进展,材料科学与工程,2001,19:108-112
[4]李世普,特种陶瓷工艺学,湖北:武汉工业大学出版社,1990,33～34
[5]Nogeira E and Edirisinghe M,Fabrication of engineering ceramics by injection moulding a suspension with optimum powder properties,J.Mater.Sci,1993,28(4):167~174
[6]Gautam B,Effects of powder characteristics on injection molding and burnout cracking,Am.Ceram.Soc.Bull,1994,73:107~114
[7]Okada K,Viscosity and powder dispersion in ceramic injection molding mixtures,J.Chem.Eng.Japan,2000,33:168~173
[8]Lin S T,Interaction between binder and powder in injection moulding of alumina,J.Mater.Sci.1994,29:5207~5212
[9]王秀,谢志鹏,李建保等,工程陶瓷注射成型的研究与发展,稀有金属材料与工程,2004,33(11),1121～1125
[10]Mangles J A,Powder Injection Molding Symposium,Am.Ceram.Soc.Bull,2004,52(2):113～114
[11]M.J.Edirisinghe,Lin S T,Hens K F,Key issues in powder injection molding,Int.J.High.Tech.Ceram,2003,43(1):1～4
[12]范景莲,黄伯云等,影响PIM发展的关键因素,粉末冶金技术,1998,16(2):217~222
[13]Kenji Okada,Viscosity and Powder Dispersion in Ceramic Injection Molding Mixtures,J. Chem. Eng. Japan.,2000,33:168~173
[14]Judith K and Mohan J,Particle packing in ceramic injection molding,J.Am.Ceram.Soc,1990,73:2653~2658
[15]German R M , Injection Molding of Metals and Ceramics ,J.Am.Ceramic.Soc.Bull.2002,79(8):129～131
[16]谢志鹏,先进陶瓷的精密注射成型,长沙理工大学学报,2006,3(3),5～9
[17]李忠权,陶瓷注射成型粘结剂现状及发展趋势,陶瓷工程,2001,6(1),35～39
[18]Wu Rong-Yuan,Torque evolution and effects on alumina feedstocks prepared by various kneading sequences,Journal of the European Ceramic Society,2000,20:67～75
[19]汪重露,陶瓷注射成型石蜡基粘结剂热脱脂行为研究,[硕士学位论文],武汉;武汉理工大学,2007
[20]吴音,ZrO2陶瓷注射成型超临界CO2流体脱脂动力学研究,硅酸盐学报,2004,32(2):134～138
[21]范景莲,李志希,肖琼等,YG8硬质合金注射成形脱脂工艺的研究,中国钨业,2004,19(5),75～80
[22]Omar M A,Ibrahim R,Rapid debinding of 316l stainless steel injection moulded component,J.Mater.Process.Technol.2003,140:397-400
[23]Bakan H I,Heaney D,German R M.,Effect of nickel boride and boron additions on sintering characteristics of injection moulded 316L powder using water soluble binder system.,Powder Metal,2001,44:235～242
[24]Yang W W and Hon M H,In situ evaluation of dimensional variations during water extraction from alumina injection-moulded parts,J.Eur.Ceram.Soc,2000,20:851～858
[25]Liang S Q,Huang B Y,Ahmad Z A,Preparation and evaluation of Al2O3 plastic forming feedstock with partially water soluble polymer as a binder ,J.Mater.Process.Technol,2003:137:128～131
[26]Thomas Y,Marple B R,Partially water-soluble binder formulation for injection molding submicrometer zirconia,Advanced Performance Materials,2001,5:25～41
[27]周吉高,李包顺,黄校先等,纳米氧化锆粉体的表面改性研究,无机材料学报,2000,11(2):237-240
[28]Tseng W J,Influence of surfactant on rheological behaviors of injection-molded alumina suspensions,Mater.Sci.Eng,2000,289:116~122
[29]Wei W J , Inffuence of stearic acid on suspension structure and green microstructure of injection-molded zirconia ceramics,Ceramics International,1999,25:191～195
[30]Trunec M,Dobsak P,Cihlar J,Effect of powder treatment on injection moulded zirconia ceramics,J.Eur.Ceram.Soc.2000,20:859～866
[31]Wei W J,Tsai S,Hsu K,Effects of mixing sequence on alumina prepared by injection molding,J.Eur.Ceram.Soc.1998,18:1445~1451
[32]李益民,黄伯云,当代金属注射成型技术,粉末冶金工业,2000,10(2):14～19
[33]李流军,金属注射成形较大尺寸件,[硕士学位论文],湖南:中南大学,2005
[34]Tseng W J,Statistical analysis of process parameters influencing dimensional control in ceramic injection molding,J.Mater.Process.Technol.1998,79:242~250
[35]Wu R,Wei W J,Torque evolution and effects on alumina feedstocks prepared by various kneading sequences,J.Eur.Ceram.Soc,2000,20:67~75
[36]雅菁,刘志锋,赵丹等,注射成型氧化铝陶瓷工艺研究,中国陶瓷,2007,43(5):14～18
[37]Paul C , Michael C , Theoretical models for binder burnout ,J.Am.Ceram.Soc.1990,73:575～579
[38]Alan W C,Stephen L J,The role of thermal and transport properties on the binder burnout of injection-moulded ceramic components,Chem.Eng.J.1998,71:243-252
[39]Liu D M,Tseng W J,Influence of debinding rate solid loading and binder formation on the green microstructure and sintering behavior of ceramic injection mouldings,Ceram.Int.1998,24:471-481
[40]Yasunari K,Norio K,Method of injection-molding zirconia ceramic,Japan,JP patent,0509625,1992-10-21
[41]Hesse W,Injection moulding and catalytic bebinding of zirconia(Y-TZP) ceramics with a polyacetal based dinder system.,Ceram.Trans.1995,51:309-313
[42]Zhang T,Evans J R,Woodthorpe J,Injection moulding of silicon carbide using an organic vehicle based on a preceramic polymer,J.Eur.Ceram.Soc,1995,15:729-734
[43]Lenk R,Adler J,SiC platelet orientation in a liquid-phase-sintered silicon carbide composite formed by thermoplastic forming techniques,J.Eur.Ceram.Soc,1997,17:197-202
[44]Smolders J S,Practical experiences with some principles pertinent to CIM,J.Eur.Ceram.Soc.1997,17:171-175
[45]Krug S,Evans J R,Maat J H,Differential sintering in ceramic injection moulding:Particle orientation effects,J.Eur.Ceram.Soc,2002,22:173-181
[46]雅菁,刘志锋,赵丹等,氧化铝陶瓷注射成型工艺的研究,天津城市建设学院学报,2007,13(3):204～207
[47]梁叔全,粉末注射成型喂料中添加剂的作用机理,材料导报,2004,18(7):19～21
[48]武斌,陶瓷注射成型及脱脂工艺研究[硕士论文],武汉:华中科技大学,2006
[49]谢志鹏,陶瓷注射成型有机载体的选择及相容性研究,硅酸盐通报,1998,20(3):8～12
[50]郭世柏,曲选辉,金属注射成形粘结剂的研究进展,粉末冶金技术,2004,22(6),178～182
[51]Ivensen V A,Densification of Metal Powders during Sintering,English Translated,New York/London Consultants Bureau,1973
[52]Hammond P , Evans J , The injection molding of ceramics ,J.Mater.Sci.Lett.1991,10:294～296
[53]Viazis A D,Cavanaugh G,Bevis R R,Bond strength of ceramic brackets under shear stress:An in vitro report,Am.J.Orthod.Dentofac.Orthop,1990,98:214～221
[54]Trunec M , Thermal debinding of injection moulded ceramics ,J.Eur.Ceram.Soc.2003,17:203~209
[55]R M German,The thermal debinding of injection molded powder compacts,Powder Met,2000,22:17～22
[56]Trunec M,Cihlar J,Thermal removal of multicomponent binder from ceramic injection moulding,J.Eur.Ceram.Soc,2002,22:2231~2241
[57]Winjea J Tseng,Cracking defect and porosity evolution during thermal debinding in ceramic injection moldings,Ceramic International,1999,25:461～466
[58]P D Hammond,J R G Evans,Thermolytic Debinding of Ceramic over Pressure,Chemical Engineering Science,1995,20:3108-3189
[2]Song J H,Evans J R,The injection molding of fine and ultra-fine zirconia powders,Ceram.Int.1995,21:325-333
[3]颜鲁婷,司文捷,苗赫濯,CIM中最新脱脂工艺的进展,材料科学与工程,2001,19:108-112
[4]李世普,特种陶瓷工艺学,湖北:武汉工业大学出版社,1990,33～34
[5]Nogeira E and Edirisinghe M,Fabrication of engineering ceramics by injection moulding a suspension with optimum powder properties,J.Mater.Sci,1993,28(4):167~174
[6]Gautam B,Effects of powder characteristics on injection molding and burnout cracking,Am.Ceram.Soc.Bull,1994,73:107~114
[7]Okada K,Viscosity and powder dispersion in ceramic injection molding mixtures,J.Chem.Eng.Japan,2000,33:168~173
[8]Lin S T,Interaction between binder and powder in injection moulding of alumina,J.Mater.Sci.1994,29:5207~5212
[9]王秀,谢志鹏,李建保等,工程陶瓷注射成型的研究与发展,稀有金属材料与工程,2004,33(11),1121～1125
[10]Mangles J A,Powder Injection Molding Symposium,Am.Ceram.Soc.Bull,2004,52(2):113～114
[11]M.J.Edirisinghe,Lin S T,Hens K F,Key issues in powder injection molding,Int.J.High.Tech.Ceram,2003,43(1):1～4
[12]范景莲,黄伯云等,影响PIM发展的关键因素,粉末冶金技术,1998,16(2):217~222
[13]Kenji Okada,Viscosity and Powder Dispersion in Ceramic Injection Molding Mixtures,J. Chem. Eng. Japan.,2000,33:168~173
[14]Judith K and Mohan J,Particle packing in ceramic injection molding,J.Am.Ceram.Soc,1990,73:2653~2658
[15]German R M , Injection Molding of Metals and Ceramics ,J.Am.Ceramic.Soc.Bull.2002,79(8):129～131
[16]谢志鹏,先进陶瓷的精密注射成型,长沙理工大学学报,2006,3(3),5～9
[17]李忠权,陶瓷注射成型粘结剂现状及发展趋势,陶瓷工程,2001,6(1),35～39
[18]Wu Rong-Yuan,Torque evolution and effects on alumina feedstocks prepared by various kneading sequences,Journal of the European Ceramic Society,2000,20:67～75
[19]汪重露,陶瓷注射成型石蜡基粘结剂热脱脂行为研究,[硕士学位论文],武汉;武汉理工大学,2007
[20]吴音,ZrO2陶瓷注射成型超临界CO2流体脱脂动力学研究,硅酸盐学报,2004,32(2):134～138
[21]范景莲,李志希,肖琼等,YG8硬质合金注射成形脱脂工艺的研究,中国钨业,2004,19(5),75～80
[22]Omar M A,Ibrahim R,Rapid debinding of 316l stainless steel injection moulded component,J.Mater.Process.Technol.2003,140:397-400
[23]Bakan H I,Heaney D,German R M.,Effect of nickel boride and boron additions on sintering characteristics of injection moulded 316L powder using water soluble binder system.,Powder Metal,2001,44:235～242
[24]Yang W W and Hon M H,In situ evaluation of dimensional variations during water extraction from alumina injection-moulded parts,J.Eur.Ceram.Soc,2000,20:851～858
[25]Liang S Q,Huang B Y,Ahmad Z A,Preparation and evaluation of Al2O3 plastic forming feedstock with partially water soluble polymer as a binder ,J.Mater.Process.Technol,2003:137:128～131
[26]Thomas Y,Marple B R,Partially water-soluble binder formulation for injection molding submicrometer zirconia,Advanced Performance Materials,2001,5:25～41
[27]周吉高,李包顺,黄校先等,纳米氧化锆粉体的表面改性研究,无机材料学报,2000,11(2):237-240
[28]Tseng W J,Influence of surfactant on rheological behaviors of injection-molded alumina suspensions,Mater.Sci.Eng,2000,289:116~122
[29]Wei W J , Inffuence of stearic acid on suspension structure and green microstructure of injection-molded zirconia ceramics,Ceramics International,1999,25:191～195
[30]Trunec M,Dobsak P,Cihlar J,Effect of powder treatment on injection moulded zirconia ceramics,J.Eur.Ceram.Soc.2000,20:859～866
[31]Wei W J,Tsai S,Hsu K,Effects of mixing sequence on alumina prepared by injection molding,J.Eur.Ceram.Soc.1998,18:1445~1451
[32]李益民,黄伯云,当代金属注射成型技术,粉末冶金工业,2000,10(2):14～19
[33]李流军,金属注射成形较大尺寸件,[硕士学位论文],湖南:中南大学,2005
[34]Tseng W J,Statistical analysis of process parameters influencing dimensional control in ceramic injection molding,J.Mater.Process.Technol.1998,79:242~250
[35]Wu R,Wei W J,Torque evolution and effects on alumina feedstocks prepared by various kneading sequences,J.Eur.Ceram.Soc,2000,20:67~75
[36]雅菁,刘志锋,赵丹等,注射成型氧化铝陶瓷工艺研究,中国陶瓷,2007,43(5):14～18
[37]Paul C , Michael C , Theoretical models for binder burnout ,J.Am.Ceram.Soc.1990,73:575～579
[38]Alan W C,Stephen L J,The role of thermal and transport properties on the binder burnout of injection-moulded ceramic components,Chem.Eng.J.1998,71:243-252
[39]Liu D M,Tseng W J,Influence of debinding rate solid loading and binder formation on the green microstructure and sintering behavior of ceramic injection mouldings,Ceram.Int.1998,24:471-481
[40]Yasunari K,Norio K,Method of injection-molding zirconia ceramic,Japan,JP patent,0509625,1992-10-21
[41]Hesse W,Injection moulding and catalytic bebinding of zirconia(Y-TZP) ceramics with a polyacetal based dinder system.,Ceram.Trans.1995,51:309-313
[42]Zhang T,Evans J R,Woodthorpe J,Injection moulding of silicon carbide using an organic vehicle based on a preceramic polymer,J.Eur.Ceram.Soc,1995,15:729-734
[43]Lenk R,Adler J,SiC platelet orientation in a liquid-phase-sintered silicon carbide composite formed by thermoplastic forming techniques,J.Eur.Ceram.Soc,1997,17:197-202
[44]Smolders J S,Practical experiences with some principles pertinent to CIM,J.Eur.Ceram.Soc.1997,17:171-175
[45]Krug S,Evans J R,Maat J H,Differential sintering in ceramic injection moulding:Particle orientation effects,J.Eur.Ceram.Soc,2002,22:173-181
[46]雅菁,刘志锋,赵丹等,氧化铝陶瓷注射成型工艺的研究,天津城市建设学院学报,2007,13(3):204～207
[47]梁叔全,粉末注射成型喂料中添加剂的作用机理,材料导报,2004,18(7):19～21
[48]武斌,陶瓷注射成型及脱脂工艺研究[硕士论文],武汉:华中科技大学,2006
[49]谢志鹏,陶瓷注射成型有机载体的选择及相容性研究,硅酸盐通报,1998,20(3):8～12
[50]郭世柏,曲选辉,金属注射成形粘结剂的研究进展,粉末冶金技术,2004,22(6),178～182
[51]Ivensen V A,Densification of Metal Powders during Sintering,English Translated,New York/London Consultants Bureau,1973
[52]Hammond P , Evans J , The injection molding of ceramics ,J.Mater.Sci.Lett.1991,10:294～296
[53]Viazis A D,Cavanaugh G,Bevis R R,Bond strength of ceramic brackets under shear stress:An in vitro report,Am.J.Orthod.Dentofac.Orthop,1990,98:214～221
[54]Trunec M , Thermal debinding of injection moulded ceramics ,J.Eur.Ceram.Soc.2003,17:203~209
[55]R M German,The thermal debinding of injection molded powder compacts,Powder Met,2000,22:17～22
[56]Trunec M,Cihlar J,Thermal removal of multicomponent binder from ceramic injection moulding,J.Eur.Ceram.Soc,2002,22:2231~2241
[57]Winjea J Tseng,Cracking defect and porosity evolution during thermal debinding in ceramic injection moldings,Ceramic International,1999,25:461～466
[58]P D Hammond,J R G Evans,Thermolytic Debinding of Ceramic over Pressure,Chemical Engineering Science,1995,20:3108-3189