Materials and Manufacturing Processes
rP Fo
Silicon Carbide Diffusion Bonding by Spark Plasma Sintering
Manuscript ID:
Date Submitted by the Author:
Original Article 03-Mar-2014
Aroshas, Ron; Ben Gurion University, Materials Engineeering Rosenthal, Idan; BGU, Stern, Adin; BGU, Shmul, Zvia; SNRC, Kalabukhov, Sergei; BGU, Frage, Nachum; BGU,
ie
6h-sic, joining, sintering, nanoindentation, microscopy, non-destructive, characterization, porosity
w
Keywords:
LMMP-2014-0061.R2
ev
Complete List of Authors:
Materials and Manufacturing Processes
rR
Manuscript Type:
ee
Journal:
ly
On URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Page 1 of 19
Abstract This work reports results of Silicon Carbide plates, disks, pipes and pipe-disk couples bonded by a Spark Plasma Sintering apparatus. The joining was conducted at 1900⁰C for thirty minutes with a 35 MPa uniaxial pressure. The samples were analysed by Scanning Acoustic Microscopy which in turn revealed a low amount of small defects at the samples' periphery. Scanning acoustic microscopy results were verified through scanning electron microscopy and nanoindentation. It was concluded that Spark
rP Fo
plasma sintering technique may serve as a valid and effective tool for diffusion bonding of high temperature resistant silicon carbide with different geometries. Keywords: Silicon Carbide, Joining, Sintering, Non-destructive, Microscopy, Nanoindentation; 1. Introduction
ee
SiC displays high hardness, elastic modulus as well as thermal stability and therefore presents high potential for a wide range of applications, including heat engines, wear
rR
parts, prosthetics, bearings, fuel cladding for advanced light water reactors, gascooled thermal and fast spectrum reactors, large telescope mirrors [1-4]. Many
ev
structural components have a complex shape and may be only fabricated using joining technologies. There are some well-known approaches of ceramics joining, such as
ie
brazing with active fillers [5,6], using transient eutectic phase [7,8], glass-ceramic joining [10, 11], reaction bonding [4, 12], sodium silicate solution bonding [13] and
w
diffusion bonding. The latter is very promising method and allows to fabricate joints with high mechanical properties of a bonded region. Diffusion bonding of SiC parts
On
requires simultaneous applying high temperature (higher than 2000°C) and pressure and usually has conducted using hot pressing equipment.
Recently, Spark Plasma Sintering (SPS) apparatus was successfully used for joining
ly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Materials and Manufacturing Processes
of similar and dissimilar ceramics, as well as ceramics to metals specimens [14-17]. Optimal joining parameters provide homogeneous structure of bonded regions and adequate mechanical properties of joints. In the present paper the results of the experimental investigation of SiC specimens joining by the SPS technique are presented and discussed.
1
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Materials and Manufacturing Processes
2. Experimental 2.1 Materials SiC plates (10x12x3 mm) and pipe samples (8 mm and 12 mm of inner and outer diameters, respectively) were purchased from the China Rare Metal Material Co., Ltd (CRM). SiC disks (12 mm diameter, 3 mm height) were prepared by SPS using grade UF-15-α SiC powder of 1 µm (H.C Starck) with average particle size of 0.55 µm and specific area of 16 m2/g. The images of the specimens are shown in Fig. 1.
rP Fo
b)
a)
c)
rR
ee Fig. 1. SiC specimens before bonding: a) rectangular plate; b) disk; c) pipe
2.2. Bonding Process
ie
ev
The joining surfaces of the samples were initially prepared by conventional methods and polished down to 1 µm. The samples were placed in a graphite die with 12 mm
w
inner and 30 mm outer diameters, and were inserted in a SPS apparatus type HP D5/1 (FCT System, Rauenstein, Germany). The bonding temperature was 1900°C with a
On
holding time of 30 min and a pressure of 35 MPa. The pulse-mode DC (pulse 5 msec and pause 2 msec) was used throughout the joining experiments.
ly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 2 of 19
2.3. Bond Characterization
Investigation of the joints included both non destructive (NDT) and destructive testing. NDT was conducted by Scanning Acoustic Microscopy (SAM), which includes a 3-D scanning system with a spatial resolution of 5 µm, acoustic pulse/receiver (model 5601 A/TT, PANAMETRICS), transducers with 15 and 25 MHz focus frequencies, data collection card (Acqiris DC140, Agilent) and image processing software. 2
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Page 3 of 19
SEM (JEOL, JSM-2500) and HRSEM (JEOL 7400F) were used for structural characterization of bonded specimens. The samples were prepared by grinding and polishing techniques. Mechanical properties of hardness and elastic modulus values were obtained by nanoindentation technique (Nano Indenter XP, MTS Systems®, Oak Ridge, TN, USA). Before each test calibration was preformed. The Continuous Stiffness Method (CSM) was applied throughout the test. A constant strain rate of 0.05 sec−1 with
rP Fo
maximum displacement set of 700 nm was used. Typically, a distance between indentations was approximately 15 µm in order to avoid the effect of neighboring indents. The output results were calculated as proposed by Oliver and Pharr [18]. 3. Results and Discussion
ee
3.1 Scanning Acoustic Microscope Typical output of a SAM for two given points of the bonded disk couple is presented
rR
in Fig. 2a,b. The presence of a reflection from the interface at point U1 indicates a lower quality of bonding, while lack of reflection from the interface at point U2 indicates an adequate bonding. The intensity of the reflection from the interface
ev
determines the quality of the bond and was calibrated with a color scale from blue to (adequate bonding) red (weak bonding) colors. Based on this scale, the reflections
ie
from all the scanned points are presented as a color map in Fig 2c. The results indicate a good bonding, with almost no defects in the central region of the specimen, while
w
lower quality of the bonding was detected at the periphery of the disks.
ly
On
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Materials and Manufacturing Processes
3
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Materials and Manufacturing Processes
ee
rP Fo Fig. 2. SAM results for disk couple: a,b) reflections from point U2 and U1,
rR
respectively; c) color map of the reflections from the interfacial plane
ev
The SAM analysis of the pipe-disk couple (Fig. 3) indicates a good bonding at the inner part of the pipe wall and lower quality of some parts close to its outer diameter.
ie
The central part of the interface is related to the geometry of the specimen (disk joined to a hollow pipe).
w ly
On
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 4 of 19
Fig. 3. SAM results for the pipe-disk couple: a) reflections from point U3; b) color map of the reflections from the interfacial plan 4
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Page 5 of 19
3.2 Light and Electron Microscopy No visible defects at the interface were detected on optical images of cross sectioned specimens after bonding (Fig 4).
rP Fo a)
b)
c)
Fig. 4. Images of cross sectioned specimens after bonding process: a) disks
couple; b) pipe-disk couple; c) pipe couple. Grooves at outer part of the specimens
ee
(marked by the arrows) were done in order to define the location of the interface after diffusion bonding
rR
Microstructure characterization of the SiC pipe and plate shaped specimens revealed their porosity of approximately 7 vol. %, while the SPS-processed disk shaped
ev
specimens were almost fully dense. From the SEM images of the cross sectioned specimens with residual porosity (Fig. 5a,b) and almost fully dense specimens (Fig.
ie
5c) the location of the interfacial zone was determine using grooves at outer part of
w
the specimens, while the bonded region is clearly detected in the pipe (porous)-disk (dense) couple.
ly
On
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Materials and Manufacturing Processes
5
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Materials and Manufacturing Processes
rP Fo
Fig. 5. SEM images of SiC specimens: a) plate couple, b) pipe couple, c) disk couple; d) pipe-disk couple; the location of bonding interface (dash red lines) was defined using grooves at outer part of the specimens
ee
3.3 Nanoindentation test
HRSEM images (Fig. 6) at significantly higher magnifications further validate the
rR
high quality of bonding. The average values of properties (hardness and elastic modulus) were calculated using only indents that aren't located on pores (Fig. 7).
w
ie
ev ly
On
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 6 of 19
Fig. 6. HRSEM images of nano-indentations across the interface: a) plate couple; b) pipe couple; c) pipe-disk couple (dash lines mark bonding interfaces).
6
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Page 7 of 19
Fig 7. HRSEM image of an indent located within a SiC grain
According to the results of nano-indentation there are no differences between
rP Fo
properties of the bonded samples far from the interface and near the bonding region.
Table 1. Elastic modulus and hardness derived from the results of nano-indentations Specimen
Average value of elastic modulus, GPa
Average values of hardness, GPa
447.0 ± 13.0
33.4 ±1.1
SiC plate couple SiC pipe couple SiC disk couple
rR
ee
483.6 ± 25.0
34.8 ± 2.9
519.6 ± 10.0
38.4 ± 1.2
ev
The properties derived from nano-indentations are presented in Table 1. These values
ie
are close to those reported in literature [19, 20] and reflect the microstructure differences between joined SiC specimens, mainly their porosity.
w
Conclusions
On
Silicon carbide parts of various geometries were joined through diffusion by using a SPS apparatus at 1900°C for 30 min under argon atmosphere (10- 2 torr). Uniaxial
ly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Materials and Manufacturing Processes
pressure of 35 MPa was applied. The results of Scanning Acoustic Microscope (SAM) analysis indicated that adequate joining was achieved and that only a few defects exist only at the periphery of the specimens. SEM images of cross-sectioned samples and nanoindentation testing validated the SAM results. Mechanical properties of the interfacial region were similar to those of the bonded specimens far from the interface.
7
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Materials and Manufacturing Processes
Acknowledgments The authors wish to thank Dr. Sidney Cohen from the Weitzman Institute for his help with Nanoindentation testing, Hagit Didi and Einav Nativ-Roth from Ben-Gurion University for contribution to SEM and HRSEM analyses.
References 1. Grasso, S.; Tatarko, P.; Rizzo, S; Porwal, H; Hu, C; Katoh, Y; Salvo, M; Reece, M.J.; Ferraris, M. Joining of β-SiC by spark plasma sintering, J. Eu. Ceram. Soc.,
rP Fo
2014, Article in press.
2. Mehregany, M.; Zorman, C.A. SiC MEMS: opportunities and challenges for applications in harsh environments, Thin Solid Films 1999, 355–356, 518- 524. 3. Okuni, T.; Miyamoto, Y.; Abe, H.; Naito, M. Joining of silicon carbide and
ee
graphite by spark plasma sintering, Ceram. Int. 2014, 40, 1359-1363. 4. Katoh, Y.; Snead, L.L.; Henager Jr., C.H.; Hasegawa, A.; Kohyama, A.; Riccardi, B.; Hegeman, H. Current status and critical issues for development of SiC
rR
composites for fusion applications, J. Nucl. Mater. 2007, 367-370, 659-671. 5. Herrmann, M.; Lippmann, W.; Hurtado, A. Y2O3-Al2O3-SiO2-based glass-ceramic
ev
fillers for the laser-supported joining of SiC, J. Eu. Ceram. Soc. 2014, Article in press.
ie
6. Pinc, W.R.; Prima, M.D; Walker, L.S; Wing, Z.N; Corral, E.L. Spark Plasma Joining of ZrB2-SiC Composites Using Zirconium-Boron Reactive Filler Layers, J. Am. Ceram. Soc. 2011, 94(11), 3825-3832.
w
7. Hinoki, T.; Eiza, N.; Son, S.; Shimoda, K.; Lee, J.; Kohyama, A. Development of
On
joining and coating technique for SiC and SiC/SiC Composites utilizing NITE processing; In: Mechanical Properties and Performance of Engineering Ceramics and Composites, Hoboken, NJ, USA, 2005; Curzio, E.L., Ed: Ceram. Eng. Sci.:
ly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 8 of 19
John Wiley & Sons, Inc., 399-405.
8. Lippmann, W.; Knorr, J.; Wolf, R.; Rasper, R.; Exner, H.; Reinecke, A.M.; Nieher, M.; Schreiber, R. Laser joining of silicon carbide - a new technology for ultra-high temperature resistant joints, Nucl. Eng. Des. 2004, 231, 151-161. 9. Gentilman, R.L.; Maguire, E.A. Chemical Vapor Deposition Of Silicon Carbide For Large Area Mirrors; In: Reflecting Optics for Synchrotron Radiation, Upton, 1981; Howells, M.R. Ed.,: SPIE. 8
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Page 9 of 19
10. Katoh, Y.; Kotani, M.; Kohyama, A.; Montorsi, M.; Salvo, M.; Ferraris, M. Microstructure and mechanical properties of low-activation glass-ceramic joining and coating for SiC/SiC composites, J. Nucl. Mater. 2000, 283, 1262-1266. 11. Ferraris, M.; Salvo, M.; Casalegno, V.; Ciampichetti, A.; Smeacetto, F.; Zucchetti, M. Joining of machined SiC/SiC composites for thermonuclear fusion reactors, J. Nucl. Mater. 2008, 375, 410-415. 12. Lewinsohn, C.A.; Jones, R.H.; Singh, M.; Nozawa, T.; Kotani, M.; Katoh, Y.; Kohyama, A. Silicon-Carbide-Based Joining Materials for Fusion Energy and
rP Fo
Other High-Temperature Structural Applications, Ceram. Eng. Sci. 2001, 22(4), 621-626.
13. Preston, A.; Mueller, G. Bonding SiC to SiC Using a Sodium Silicate Solution, Int. J. Appl. Ceram. Technol. 2012, 9(4), 764-771.
ee
14. Miriyev, A.; Stern, A.; Tuval, E.; Kalabukhov, S.; Hooper, Z.; Frage, N. Titanium to steel joining by spark plasma sintering (SPS) technology, J. Mater. Process Tech 2013, 213, 161-166.
rR
15. Bi, D.M.; Zhi, W.; Qin, W.G. Exploration of Joining Between Ceramics and Steels: An Example Using the Spark Plasma Sintering Technique, J. Phase Eq. Diff. 2010, 32(3), 178-182.
ev
16. Luo, Y.; Li, S.; Pan, W.; Li, L. Fabrication and mechanical evaluation of SiC-TiC
ie
nanocomposites by SPS, Mater. Lett. 2004, 58, 150-153. 17. Stern, A.; Rosenthal, I.; Aroshas, R.; Kalabukhov, S.; Dariel, M.P.; Frage, N.
w
Silicon Carbide Bonding for High Temperatures Resistant Joints, The Annals of “Dunarea de Jos” University, Fascicle XII, Welding Equipment and Technology
On
2012, 23, 5-10.
18. Oliver, W.C.; Pharr, G.M. An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments, J.
ly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Materials and Manufacturing Processes
Mater. Res. 1992, 7(6), 1564-1583.
19. Ctvrtlik, R.; Kulikovsky, V.; Vorlicek, V.; Bohac, P.; Stranyanek, M. Effect of structure on mechanical properties of covalent ceramics, Nanocon Conference, Olomouc, 2010. 20. Angle, J. Nanoindentation of silicon carbide wafer coatings, Nanovea Mechanical Testing Brochure, 2010.
9
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Materials and Manufacturing Processes
Silicon Carbide Diffusion Bonding by Spark Plasma
rP Fo
Sintering
R. Aroshasa, A. Sterna, I. Rosenthala, Z. Shmulb, S. Kalabukhova and N. Fragea
a
ee
Department of Material Engineering, Ben-Gurion University,
rR
P.O. Box 653, Beer-Sheva 84105, Israel b
Soreq Nuclear Research Center, Israel
w
ie
ev ly
On
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 10 of 19
1
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Page 11 of 19
Abstract This work reports results of Silicon Carbide plates, disks, pipes and pipe-disk couples bonded by a Spark Plasma Sintering apparatus. The joining was conducted at 1900⁰C for 30 min under a 35 MPa uniaxial pressure. The samples were analysed by Scanning Acoustic Microscopy which in turn revealed a low amount of small defects at the samples' periphery. Scanning acoustic microscopy results were verified through scanning electron microscopy and nanoindentation. It was concluded that Spark
rP Fo
plasma sintering technique may serve as a valid and effective tool for diffusion bonding of high temperature resistant silicon carbide with different geometries. Keywords: Silicon Carbide, Joining, Sintering, Non-destructive, Microscopy, Nanoindentation; 1. Introduction
ee
SiC displays high hardness, elastic modulus as well as thermal stability and therefore is a promising material for a wide range of applications, including heat engines, wear
rR
parts, prosthetics, bearings, fuel cladding for advanced light water reactors, gascooled thermal and fast spectrum reactors, large telescope mirrors [1-4]. Many
ev
structural components have a complex shape and may be only fabricated using joining technologies. There are some well-known approaches of ceramics joining, such as
ie
brazing with active fillers [5,6], using transient eutectic phase [7,8], glass-ceramic joining [10, 11], reaction bonding [4, 12], sodium silicate solution bonding [13] and
w
diffusion bonding. The latter is very promising method and allows to fabricate joints with high mechanical properties of a bonded region. Diffusion bonding of SiC parts
On
requires simultaneous applying high temperature (higher than 2000°C) and pressure and usually has conducted using hot pressing equipment.
Recently, Spark Plasma Sintering (SPS) apparatus was successfully used for joining
ly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Materials and Manufacturing Processes
of similar and dissimilar ceramics, as well as ceramics to metals specimens [14-17]. Optimal joining parameters provide homogeneous structure of bonded regions and adequate mechanical properties of joints. In the present paper the results of the experimental investigation of SiC specimens joining by the SPS technique are presented and discussed.
2
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Materials and Manufacturing Processes
2. Experimental 2.1 Materials SiC plates (10x12x3 mm) and pipe samples (8 mm and 12 mm of inner and outer diameters, respectively) were purchased from the China Rare Metal Material Co., Ltd (CRM). SiC disks (12 mm diameter, 3 mm height) were prepared by SPS using grade UF-15-α SiC powder of 1 µm (H.C Starck) with average particle size of 0.55 µm and specific area of 16 m2/g. The images of the specimens are presented in Fig 1.
rP Fo
b)
a)
c)
rR
ee Fig. 1. SiC specimens before bonding: a) rectangular plate; b) disk; c) pipe
2.2. Bonding Process
ie
ev
The mating surfaces of the samples were prepared by conventional metallographic techniques with 1 µm finish diamond paste, cleaned in acetone and dried in air. The
w
assembly was placed in a graphite die with 12 mm inner and 30 mm outer diameters, and was inserted in a SPS apparatus equipped with a 50 kN uniaxial press, type HP
On
D5/1 (FCT System, Rauenstein, Germany). SPS bonding process was carried out at 1900°C for 30 min under argon atmosphere (10-2 torr). Uniaxial pressure of 35 MPa was applied while the pulse-mode DC current (pulse 5msec and pause 2msec) was
ly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 12 of 19
used throughout the joining experiments. 2.3. Bond Characterization
In order to evaluate the quality of the joints both nondestructive (NDT) and destructive tests were performed. NDT was conducted by Scanning Acoustic Microscopy (SAM), which includes a 3-D scanning system with a spatial resolution of 5 µm, acoustic pulse/receiver (model 5601 A/TT, PANAMETRICS), transducers 3
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Page 13 of 19
with 15 and 25 MHz focus frequencies, data collection card (Acqiris DC140, Agilent) and image processing software. Optical Microscope (OM Zeiss, Aalen, Germany), Scanning Electron Microscope (SEM JEOL, JSM-2500) and High Resolution Scanning Electron Microscope (HRSEM, JEOL 7400F) were used for structural characterization of bonded specimens. The samples were cross-sectioned and prepared by conventional grinding and polishing techniques.
rP Fo
Measurements of hardness and elastic modulus were conducted (Nano Indenter XP, MTS Systems®, Oak Ridge, TN, USA), using a Berkovich indenter. Prior to each experiment the indenter head was optically calibrated to ensure stage movement accuracy and the precise location of the indenter tip. The Continuous Stiffness
ee
Method (CSM) was applied throughout the test, whereby a small (2 nm or less) modulation is related to the indenting tip. Indentations were performed at a constant strain rate of 0.05 sec−1 under displacement control, with maximum displacement set
rR
of 700 nm. Typically, a distance between indentations was approximately 15 µm in order to avoid the effect of neighboring indents. The output results were treated
ev
according to the basic equations developed by Oliver and Pharr [18]. 3. Results and Discussion
ie
3.1 Scanning Acoustic Microscope
w
Typical output of a SAM for two given points of the bonded disk couple is presented in Fig. 2a,b. The presence of a reflection from the interface at point U1 indicates a
On
lower quality of bonding, while lack of reflection from the interface at point U2 indicates an adequate bonding. The intensity of the reflection from the interface determines the quality of the bond and was calibrated with a color scale from blue to
ly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Materials and Manufacturing Processes
(adequate bonding) red (weak bonding) colors. Based on this scale, the reflections from all the scanned points are presented as a color map in Fig 2c. The results indicate a good bonding, with almost no defects in the central region of the specimen, while lower quality of the bonding was detected at the periphery of the disks.
4
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Materials and Manufacturing Processes
ee
rP Fo Fig. 2. SAM results for disk couple: a,b) reflections from point U2 and U1,
rR
respectively; c) color map of the reflections from the interfacial plane
ev
The SAM analysis of the pipe-disk couple (Fig. 3) indicates a good bonding at the inner part of the pipe wall and lower quality of some parts close to its outer diameter.
ie
The central part of the interface is related to the geometry of the specimen (disk joined to a hollow pipe).
w ly
On
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 14 of 19
Fig. 3. SAM results for the pipe-disk couple: a) reflections from point U3; b) color map of the reflections from the interfacial plan 5
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Page 15 of 19
3.2 Light and Electron Microscopy No visible defects at the interface were detected on optical images of cross sectioned specimens after bonding (Fig 4).
rP Fo a)
b)
c)
Fig. 4. Images of cross sectioned specimens after bonding process: a) disks
couple; b) pipe-disk couple; c) pipe couple. Grooves at outer part of the specimens
ee
(marked by the arrows) were done in order to define the location of the interface after diffusion bonding
rR
Microstructure characterization of the SiC pipe and plate shaped specimens revealed their porosity of approximately 7 vol. %, while the SPS-processed disk shaped
ev
specimens were almost fully dense. From the SEM images of the cross sectioned specimens with residual porosity (Fig. 5a,b) and almost fully dense specimens (Fig.
ie
5c) the location of the interfacial zone was determine using grooves at outer part of
w
the specimens, while the bonded region is clearly detected in the pipe (porous)-disk (dense) couple.
ly
On
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Materials and Manufacturing Processes
6
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Materials and Manufacturing Processes
rP Fo
Fig. 5. SEM micrographs of SiC specimens: a) plate couple, b) pipe couple, c) disk
ee
couple; d) pipe-disk couple; the location of bonding interface (dash red lines) was defined using grooves at outer part of the specimens
rR
HRSEM images (Fig. 6) at significantly higher magnifications further validate the high quality of bonding.
ie
3.3 Nanoindentation test
ev
In order to evaluate the mechanical properties of the bonded specimens, nanoindentation (Fig. 6) was conducted. Average values of hardness and elastic modulus
w
were calculated using only indents that aren't located on pores (Fig. 7).
ly
On
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 16 of 19
Fig. 6. HRSEM images of nano-indentations across the interface: a) plate couple; b) pipe couple; c) pipe-disk couple (dash lines mark bonding interfaces).
7
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Page 17 of 19
Fig 7. HRSEM image of an indent located within a SiC grain
rP Fo
According to the results of nano-indentation there are no differences between properties of the bonded samples far from the interface and near the bonding region.
Table 1. Average values of elastic modulus and hardness derived from the results of
ee
nano-indentations:
Specimen
SiC plate couple
SiC disk couple
Average values of hardness, GPa
447.0 ± 13.0
33.4 ±1.1
483.6 ± 25.0
34.8 ± 2.9
519.6 ± 10.0
38.4 ± 1.2
ie
ev
SiC pipe couple
Average value of elastic modulus, GPa
rR
Average values of elastic modulus and hardness are presented in Table 1. These
w
values are close to those reported in literature [19, 20] and reflect the microstructure differences between joined SiC specimens, mainly their porosity.
On
Conclusions
ly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Materials and Manufacturing Processes
Silicon carbide parts of various geometries were joined through diffusion by using a SPS apparatus at 1900°C for 30 min under argon atmosphere (10- 2 torr). Uniaxial pressure of 35 MPa was applied. The results of Scanning Acoustic Microscope (SAM) analysis indicated that adequate joining was achieved and that only a few defects exist only at the periphery of the specimens. SEM images of cross-sectioned samples and nanoindentation testing validated the SAM results. Mechanical properties of the interfacial region were similar to those of the bonded specimens far from the interface. 8
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Materials and Manufacturing Processes
Acknowledgments The author would like to thank Dr. Sidney Cohen from the Weitzman Institute for his help with Nanoindentation testing, Hagit Didi and Einav Nativ-Roth from Ben-Gurion University for contribution to SEM and HRSEM analyses.
References 1. Grasso, S.; Tatarko, P.; Rizzo, S; Porwal, H; Hu, C; Katoh, Y; Salvo, M; Reece, M.J.; Ferraris, M. Joining of β-SiC by spark plasma sintering, J. Eu. Ceram. Soc.,
rP Fo
2014, Article in press.
2. Mehregany, M.; Zorman, C.A. SiC MEMS: opportunities and challenges for applications in harsh environments, Thin Solid Films 1999, 355–356, 518- 524. 3. Okuni, T.; Miyamoto, Y.; Abe, H.; Naito, M. Joining of silicon carbide and
ee
graphite by spark plasma sintering, Ceram. Int. 2014, 40, 1359-1363. 4. Katoh, Y.; Snead, L.L.; Henager Jr., C.H.; Hasegawa, A.; Kohyama, A.; Riccardi, B.; Hegeman, H. Current status and critical issues for development of SiC
rR
composites for fusion applications, J. Nucl. Mater. 2007, 367-370, 659-671. 5. Herrmann, M.; Lippmann, W.; Hurtado, A. Y2O3-Al2O3-SiO2-based glass-ceramic
ev
fillers for the laser-supported joining of SiC, J. Eu. Ceram. Soc. 2014, Article in press.
ie
6. Pinc, W.R.; Prima, M.D; Walker, L.S; Wing, Z.N; Corral, E.L. Spark Plasma Joining of ZrB2-SiC Composites Using Zirconium-Boron Reactive Filler Layers, J. Am. Ceram. Soc. 2011, 94(11), 3825-3832.
w
7. Hinoki, T.; Eiza, N.; Son, S.; Shimoda, K.; Lee, J.; Kohyama, A. Development of
On
joining and coating technique for SiC and SiC/SiC Composites utilizing NITE processing; In: Mechanical Properties and Performance of Engineering Ceramics and Composites, Hoboken, NJ, USA, 2005; Curzio, E.L., Ed: Ceram. Eng. Sci.:
ly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 18 of 19
John Wiley & Sons, Inc., 399-405.
8. Lippmann, W.; Knorr, J.; Wolf, R.; Rasper, R.; Exner, H.; Reinecke, A.M.; Nieher, M.; Schreiber, R. Laser joining of silicon carbide - a new technology for ultra-high temperature resistant joints, Nucl. Eng. Des. 2004, 231, 151-161. 9. Gentilman, R.L.; Maguire, E.A. Chemical Vapor Deposition Of Silicon Carbide For Large Area Mirrors; In: Reflecting Optics for Synchrotron Radiation, Upton, 1981; Howells, M.R. Ed.,: SPIE. 9
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
Page 19 of 19
10. Katoh, Y.; Kotani, M.; Kohyama, A.; Montorsi, M.; Salvo, M.; Ferraris, M. Microstructure and mechanical properties of low-activation glass-ceramic joining and coating for SiC/SiC composites, J. Nucl. Mater. 2000, 283, 1262-1266. 11. Ferraris, M.; Salvo, M.; Casalegno, V.; Ciampichetti, A.; Smeacetto, F.; Zucchetti, M. Joining of machined SiC/SiC composites for thermonuclear fusion reactors, J. Nucl. Mater. 2008, 375, 410-415. 12. Lewinsohn, C.A.; Jones, R.H.; Singh, M.; Nozawa, T.; Kotani, M.; Katoh, Y.; Kohyama, A. Silicon-Carbide-Based Joining Materials for Fusion Energy and
rP Fo
Other High-Temperature Structural Applications, Ceram. Eng. Sci. 2001, 22(4), 621-626.
13. Preston, A.; Mueller, G. Bonding SiC to SiC Using a Sodium Silicate Solution, Int. J. Appl. Ceram. Technol. 2012, 9(4), 764-771.
ee
14. Miriyev, A.; Stern, A.; Tuval, E.; Kalabukhov, S.; Hooper, Z.; Frage, N. Titanium to steel joining by spark plasma sintering (SPS) technology, J. Mater. Process Tech 2013, 213, 161-166.
rR
15. Bi, D.M.; Zhi, W.; Qin, W.G. Exploration of Joining Between Ceramics and Steels: An Example Using the Spark Plasma Sintering Technique, J. Phase Eq. Diff. 2010, 32(3), 178-182.
ev
16. Luo, Y.; Li, S.; Pan, W.; Li, L. Fabrication and mechanical evaluation of SiC-TiC
ie
nanocomposites by SPS, Mater. Lett. 2004, 58, 150-153. 17. Stern, A.; Rosenthal, I.; Aroshas, R.; Kalabukhov, S.; Dariel, M.P.; Frage, N.
w
Silicon Carbide Bonding for High Temperatures Resistant Joints, The Annals of “Dunarea de Jos” University, Fascicle XII, Welding Equipment and Technology
On
2012, 23, 5-10.
18. Oliver, W.C.; Pharr, G.M. An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments, J.
ly
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Materials and Manufacturing Processes
Mater. Res. 1992, 7(6), 1564-1583.
19. Ctvrtlik, R.; Kulikovsky, V.; Vorlicek, V.; Bohac, P.; Stranyanek, M. Effect of structure on mechanical properties of covalent ceramics, Nanocon Conference, Olomouc, 2010. 20. Angle, J. Nanoindentation of silicon carbide wafer coatings, Nanovea Mechanical Testing Brochure, 2010.
10
URL: http://mc.manuscriptcentral.com/lmmp Email:
[email protected]
