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Processes for joining metals to ceramics
RELATIONSHIP BETWEEN CARBON CHEMISTRY AND THERMAL CRACKING RESISTANCE OF CARBIDE MILLING I N S E R T S
A1203 and the fracture to be t r a n s g r a n u l a r a n d i n t e r g r a n u l a r in m o n o l i t h i c A1203. After HIP the fracture s t r e n g t h exceeded 1000 MPa.
J.E. Peters a n d B. Hoefler ( A m e r i c a n National C a r b i d e Co., Houston, Texas, USA), Int J Refractory Metals & Hard Materials, Vol 11, No 3, 1992, 159-163. An investigation of the thermal (:racking resistance of WC-8.5 wt% TaC-11% Co with 0.02, 0.05 or 0.1% C a d d e d is described. It is shown thai the material with the greatest resistance to thermal cracking also has the highest residual compressive stress which is s h o w n to d e p e n d on t h e c a r b o n stoichometry and binder p h a s e chemistry.
FABRICATION AND MICROSTRUCTURE OF SILICON NITRIDEMETAL NITRIDE NANOCOMPOSITES
DENSIFICATION AND PROPERTIES OF ALUMINA-NICKEL CERMET WITH TITANIUM NITRIDE INTERLAYER S. Li et al (University of Twente, Enschede, The Netherlands), Int J Refractory Metals & Hard Materials, Vol 11, No 3, 1992, 181192. The production of Al20:~-Ni cermets is discussed. A120:~ was coated with TiN by chemical vapour deposition, mixed with Ni powder and consolidated by c o l d compaction and hot pressing. It is shown t h a t the p r o p e r t i e s of t h e c e r m e t are i m p r o v e d by t h e p r e s e n c e of t h e TiN interlayer. MICROSTRUCTURE OF ALUMINANICKEL C E R M E T WITH TITANIUM NITRIDE INTERLAYER S. Li et al (University of Twente, Enschede, The Netherlands), lnt J Refractory Metals & Hard Material,s, Vol l 1, No 3, 1992, 19320O. The microstruetures of Al20:~-Ni cermets, produced from Al,~O:~ powder coated with TiN and Ni powder, were investigated. High bond strengths at the AI~:O:~-TiN and Ni-TiN interfaces but not at the A120:~-Ni interface, due to lack of adhesion, are reported. These are considered tot be responsible for the improvements in properties of the AlzO aTiN-Ni cermets. FABRICATION AND PROPERTIES OF P R E S S U R E L E S S S I N T E R E D ALUMINASILICON CARBIDE NANOCOMPOSITES M. lshitlsuka and M. Tamai (Sumitomo Cement Co., Funabashi, J a p a n ) , J Japan
Soc. Powder and
Powder Metallurgy,
Vol 39, No 12, 1992, 11()9-1112. (In Japanese), The production of A1203-SiC composites from 4 nm AI~O3 and 20 nm SiC powders is described. The particles of the composite powder are shown to have a two p h a s e structure. Pressureless sintering was studied by electron microscopy and it is shown t h a i t h e s t r u c t u r e c o n s i s t e d of p a r t i c l e s of SiC in t h e A1203 m a t r i x g r a i n s . The f r a c t u r e s t r e n g t h of t h e composite is reported to be higher t h a n
J-J. Matsui et al ( S u r n i t o m o E l e c t r i c Industries, Itamai, J a p a n ) J Japan Soc Powder and Powder Metallurgy, Vol 39, No 12, 1992, 1119-1123. (In J a p a n e s e ) . It is s h o w n t h a t t h e a d d i t i o n o f nanosized particles of TiN to SiuN 4 results in i n c r e a s e d fracture t o u g h n e s s of t h e consolidated materials. The structure is shown to be a very fine dispersion of TiN in the SiaN4 grains. VACUUM SINTERING OF T U N G S T E N CARBIDE A. Doubravsky and P. Sindler Cgyzkumny Ustav Praskove Metall, Sumperk, Czechoslovakia), Pokroky Psaskove Metalurgie, No 1, 1993, 12-22. (In Czech). E x p e r i m e n t s on t h e d e w a x i n g a n d sintering of WC-Co in a vacuum furnace are described. Variables investigated included %Co, addition of TaC and NbC and lubricant composition. E F F E C T S OF MILLING M E T H O D S ON REACTION OF TITANIUM CARBIDE FORMATION S. Wanikewa a n d T. Takeda (National Research Inst for Metals, Tokyo, J a p a n ) , J
Japan Soc Powder and Powder Metallurgy, Vol 39, No 12, 1992, 1145-1150. (In Japanese). An investigation, in which Ti and C powders were milled in different types of mill, is described. Reaction between Ti and C powders, to form TiC, was monitored by m e a s u r e m e n t of mill temperature. Clear indications of reaction were obtained. Ball size is reported to have a significant effect on the reaction. PHASE CHANGES IN ELECTROSPARK MACHINED AND A N N E A L E D T U N G S T E N CARBIDE N.Tsuchiya et al (Fuji Die Co., Tokyo, J a p a n ) , J Japan Soc Powder and Powder Metallurgy, Vol 39, No 12, 1992, 11511156. (In J a p a n e s e ) . Sintered WC c o m p a c t s were m a c h i n e d by electric discharge and t h e n annealed at 800 to 1300 °C for up to 80 hours. Phase changes, WC to ¢¢WC1 x and W2C in the m a c h i n e d s u r f a c e w e r e d e t e r m i n e d as functions of annealing t e m p e r a t u r e and time. The p h a s e s are r e p o r t e d to revert to WC. Two e u t e c t o i d m e c h a n i s m s a r e suggested by way of explanation. CHEMICAL VAPOUR DEPOSITION OF SILICON NITRIDE PLATES J.W. Lennartz and M.B. Dowell
(Union
Carbide Corp, Parma, Ohio, USA), Materials and Manufacturing Processes, Vol 8, No 3, 1993, 331-339. Chemical vapour deposition (CVD) of thick layers 0.5 to 4 m m thick on various substrate were formed. Si3N a is r e p o r t e d to be of theoretical density with grains 0.05 to 1 m m in size. The crystal orientation is said to be p r e f e r r e d w i t h t h e f~ d i r e c t i o n p e r p e n d i c u l a r to the substrate surface. P R O C E S S E S FOR JOINING METALS TO CERAMICS J. I n t r a t e r (Advanced Technology Inc., San Jose, California, USA), Materials and Manufacturing Processes, Vol 8, No 3, 1993, 353-373. Methods of joining of metals to ceramics, cermets and hard metals, including refractory metallization and active metal brazing, are d i s c u s s e d with r e s p e c t to processing and applications. The p r o b l e m s of b o n d i n g i n c o m p u t a b l e materials are addressed. EXPLOSIVE CHARACTERISTICS OF TITANIUM CARBIDE AND HIGH S P E E D STEEL POWDERS G.I. Vasilieva, Poroshkovaya Metallurgiya, No 5, 1992, 102-104. (In Russian). The explosive characteristics of pseudomelted TiC and HSS and their mixtm'es were investigated with reference to flame p r o p a g a t i o n in a i r - p o w d e r m i x t u r e s , explosion pressure, pressure growth u n d e r explosion in m a x i m u m O c o n t e n t a n d pryophoric properties of the powders. E F F E C T OF WHISKER ORIENTATION ON P R E S S U R E - L E S S SINTERING DENSIFICATION OF SILICON CARBIDE R E I N F O R C E D SILICON NITRIDE W-S. Cho and K. Hayashi (University of Tokyo, Tokyo, J a p a n ) , J Japan Soc Powder and Powder Metallurgy, Vol 40, No l, 1993, 16-19. (In J a p a n e s e ) . The effect of unidirectional orientation SiC whisker reinforcement on Si:~N4 was investigated with respect to SiC c o n t e n t and whisker aspect :ratios. It is r e p o r t e d t h a t unidirectional orientation in whisker reinforcement is beneficial in promoting densification but the m a x i m u m densities were limited to 92% at 15vo1% SiC and 86% at 20vo1%. EXPLOSIVENESS OF POWDER MIXTURES MADE FROM CARBIDE S T E E L S G.I. Vasilieva, V.G. Tokhtuev, Poroshkovaya No 5, 1992, 102-104, (In Russian). The explosive characteristics of pseudomelted TiC and high speed steel powders and their m i x t u r e s were investigated with reference to flame p r o p a g a t i o n in air/ powder mixtures, explosion pressures, pressure growth during combustion, m a x i m u m O c o n t e n t in the media and the pyrophoric properties of the powder.
Metallurgiya,
MPR July\August 1993 47
A1203 and the fracture to be t r a n s g r a n u l a r a n d i n t e r g r a n u l a r in m o n o l i t h i c A1203. After HIP the fracture s t r e n g t h exceeded 1000 MPa.
J.E. Peters a n d B. Hoefler ( A m e r i c a n National C a r b i d e Co., Houston, Texas, USA), Int J Refractory Metals & Hard Materials, Vol 11, No 3, 1992, 159-163. An investigation of the thermal (:racking resistance of WC-8.5 wt% TaC-11% Co with 0.02, 0.05 or 0.1% C a d d e d is described. It is shown thai the material with the greatest resistance to thermal cracking also has the highest residual compressive stress which is s h o w n to d e p e n d on t h e c a r b o n stoichometry and binder p h a s e chemistry.
FABRICATION AND MICROSTRUCTURE OF SILICON NITRIDEMETAL NITRIDE NANOCOMPOSITES
DENSIFICATION AND PROPERTIES OF ALUMINA-NICKEL CERMET WITH TITANIUM NITRIDE INTERLAYER S. Li et al (University of Twente, Enschede, The Netherlands), Int J Refractory Metals & Hard Materials, Vol 11, No 3, 1992, 181192. The production of Al20:~-Ni cermets is discussed. A120:~ was coated with TiN by chemical vapour deposition, mixed with Ni powder and consolidated by c o l d compaction and hot pressing. It is shown t h a t the p r o p e r t i e s of t h e c e r m e t are i m p r o v e d by t h e p r e s e n c e of t h e TiN interlayer. MICROSTRUCTURE OF ALUMINANICKEL C E R M E T WITH TITANIUM NITRIDE INTERLAYER S. Li et al (University of Twente, Enschede, The Netherlands), lnt J Refractory Metals & Hard Material,s, Vol l 1, No 3, 1992, 19320O. The microstruetures of Al20:~-Ni cermets, produced from Al,~O:~ powder coated with TiN and Ni powder, were investigated. High bond strengths at the AI~:O:~-TiN and Ni-TiN interfaces but not at the A120:~-Ni interface, due to lack of adhesion, are reported. These are considered tot be responsible for the improvements in properties of the AlzO aTiN-Ni cermets. FABRICATION AND PROPERTIES OF P R E S S U R E L E S S S I N T E R E D ALUMINASILICON CARBIDE NANOCOMPOSITES M. lshitlsuka and M. Tamai (Sumitomo Cement Co., Funabashi, J a p a n ) , J Japan
Soc. Powder and
Powder Metallurgy,
Vol 39, No 12, 1992, 11()9-1112. (In Japanese), The production of A1203-SiC composites from 4 nm AI~O3 and 20 nm SiC powders is described. The particles of the composite powder are shown to have a two p h a s e structure. Pressureless sintering was studied by electron microscopy and it is shown t h a i t h e s t r u c t u r e c o n s i s t e d of p a r t i c l e s of SiC in t h e A1203 m a t r i x g r a i n s . The f r a c t u r e s t r e n g t h of t h e composite is reported to be higher t h a n
J-J. Matsui et al ( S u r n i t o m o E l e c t r i c Industries, Itamai, J a p a n ) J Japan Soc Powder and Powder Metallurgy, Vol 39, No 12, 1992, 1119-1123. (In J a p a n e s e ) . It is s h o w n t h a t t h e a d d i t i o n o f nanosized particles of TiN to SiuN 4 results in i n c r e a s e d fracture t o u g h n e s s of t h e consolidated materials. The structure is shown to be a very fine dispersion of TiN in the SiaN4 grains. VACUUM SINTERING OF T U N G S T E N CARBIDE A. Doubravsky and P. Sindler Cgyzkumny Ustav Praskove Metall, Sumperk, Czechoslovakia), Pokroky Psaskove Metalurgie, No 1, 1993, 12-22. (In Czech). E x p e r i m e n t s on t h e d e w a x i n g a n d sintering of WC-Co in a vacuum furnace are described. Variables investigated included %Co, addition of TaC and NbC and lubricant composition. E F F E C T S OF MILLING M E T H O D S ON REACTION OF TITANIUM CARBIDE FORMATION S. Wanikewa a n d T. Takeda (National Research Inst for Metals, Tokyo, J a p a n ) , J
Japan Soc Powder and Powder Metallurgy, Vol 39, No 12, 1992, 1145-1150. (In Japanese). An investigation, in which Ti and C powders were milled in different types of mill, is described. Reaction between Ti and C powders, to form TiC, was monitored by m e a s u r e m e n t of mill temperature. Clear indications of reaction were obtained. Ball size is reported to have a significant effect on the reaction. PHASE CHANGES IN ELECTROSPARK MACHINED AND A N N E A L E D T U N G S T E N CARBIDE N.Tsuchiya et al (Fuji Die Co., Tokyo, J a p a n ) , J Japan Soc Powder and Powder Metallurgy, Vol 39, No 12, 1992, 11511156. (In J a p a n e s e ) . Sintered WC c o m p a c t s were m a c h i n e d by electric discharge and t h e n annealed at 800 to 1300 °C for up to 80 hours. Phase changes, WC to ¢¢WC1 x and W2C in the m a c h i n e d s u r f a c e w e r e d e t e r m i n e d as functions of annealing t e m p e r a t u r e and time. The p h a s e s are r e p o r t e d to revert to WC. Two e u t e c t o i d m e c h a n i s m s a r e suggested by way of explanation. CHEMICAL VAPOUR DEPOSITION OF SILICON NITRIDE PLATES J.W. Lennartz and M.B. Dowell
(Union
Carbide Corp, Parma, Ohio, USA), Materials and Manufacturing Processes, Vol 8, No 3, 1993, 331-339. Chemical vapour deposition (CVD) of thick layers 0.5 to 4 m m thick on various substrate were formed. Si3N a is r e p o r t e d to be of theoretical density with grains 0.05 to 1 m m in size. The crystal orientation is said to be p r e f e r r e d w i t h t h e f~ d i r e c t i o n p e r p e n d i c u l a r to the substrate surface. P R O C E S S E S FOR JOINING METALS TO CERAMICS J. I n t r a t e r (Advanced Technology Inc., San Jose, California, USA), Materials and Manufacturing Processes, Vol 8, No 3, 1993, 353-373. Methods of joining of metals to ceramics, cermets and hard metals, including refractory metallization and active metal brazing, are d i s c u s s e d with r e s p e c t to processing and applications. The p r o b l e m s of b o n d i n g i n c o m p u t a b l e materials are addressed. EXPLOSIVE CHARACTERISTICS OF TITANIUM CARBIDE AND HIGH S P E E D STEEL POWDERS G.I. Vasilieva, Poroshkovaya Metallurgiya, No 5, 1992, 102-104. (In Russian). The explosive characteristics of pseudomelted TiC and HSS and their mixtm'es were investigated with reference to flame p r o p a g a t i o n in a i r - p o w d e r m i x t u r e s , explosion pressure, pressure growth u n d e r explosion in m a x i m u m O c o n t e n t a n d pryophoric properties of the powders. E F F E C T OF WHISKER ORIENTATION ON P R E S S U R E - L E S S SINTERING DENSIFICATION OF SILICON CARBIDE R E I N F O R C E D SILICON NITRIDE W-S. Cho and K. Hayashi (University of Tokyo, Tokyo, J a p a n ) , J Japan Soc Powder and Powder Metallurgy, Vol 40, No l, 1993, 16-19. (In J a p a n e s e ) . The effect of unidirectional orientation SiC whisker reinforcement on Si:~N4 was investigated with respect to SiC c o n t e n t and whisker aspect :ratios. It is r e p o r t e d t h a t unidirectional orientation in whisker reinforcement is beneficial in promoting densification but the m a x i m u m densities were limited to 92% at 15vo1% SiC and 86% at 20vo1%. EXPLOSIVENESS OF POWDER MIXTURES MADE FROM CARBIDE S T E E L S G.I. Vasilieva, V.G. Tokhtuev, Poroshkovaya No 5, 1992, 102-104, (In Russian). The explosive characteristics of pseudomelted TiC and high speed steel powders and their m i x t u r e s were investigated with reference to flame p r o p a g a t i o n in air/ powder mixtures, explosion pressures, pressure growth during combustion, m a x i m u m O c o n t e n t in the media and the pyrophoric properties of the powder.
Metallurgiya,
MPR July\August 1993 47