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Journal ArticleDOI

Active Metal Brazing of Machinable Aluminum Nitride-Based Ceramic to Stainless Steel

17 Jan 2012-Journal of Materials Engineering and Performance (Springer US)-Vol. 21, Iss: 5, pp 671-677
TL;DR: Shapal™-M machinable AlN-based ceramic and AISI 304 stainless steel were joined by active metal brazing, at 750, 800, and 850 °C, with a dwell stage of 10 min at the processing temperature, using a 59Ag-2725Cu-125In-125Ti (wt%) filler foil as mentioned in this paper.
Abstract: Shapal™-M machinable AlN-based ceramic and AISI 304 stainless steel were joined by active metal brazing, at 750, 800, and 850 °C, with a dwell stage of 10 min at the processing temperature, using a 59Ag-2725Cu-125In-125Ti (wt%) filler foil The influences of temperature on the microstructural features of brazed interfaces and on the shear strength of joints were assessed The interfacial microstructures were analyzed by scanning electron microscopy (SEM), and the composition of the phases detected at the interfaces was evaluated by energy dispersive X-ray spectroscopy (EDS) The fracture surfaces of joints were analyzed by SEM, EDS, and GIXRD (Grazing Incidence X-Ray Diffraction) Reaction between the liquid braze and both base materials led to the formation of a Ti-rich layer, adjacent to each base material Between the Ti-rich layers, the interfaces consist of a (Ag) solid-solution matrix, where coarse (Cu) particles and either Cu-In or Cu-In-Ti and Cu-Ti intermetallics phases are dispersed The stronger joints, with shear strength of 220 ± 32 MPa, were produced after brazing at 800 °C Fracture of joints occurred preferentially not only through the ceramic sample but also across the adjoining TiN layer, independent of the brazing temperature

Summary (1 min read)

1. Introduction

  • Aluminum nitride (AlN) exhibits, among ceramics, a unique combination of properties such as high thermal conductivity, high electrical resistivity, low coefficient of thermal expansion, low dielectric constant (Ref 1), large band gap, good thermal shock resistance, and excellent corrosion resistance to plasma and halogen gases (Ref 1, 2).
  • Applications of AlN include electronic substrates and packaging, high-frequency acoustic wave devices, light-emitting diodes, andwide band gap semiconductors (Ref 1).
  • Like other ceramics, AlN is intrinsically brittle and thus, production of AlN components with intricate shape is problematic.
  • As AlN (Ref 6), the joining of Shapal!-M to stainless steels may be required for thermomechanical applications.
  • These joining routes may be suitable to produce Shapal!-M joints but, to their best knowledge, there are no reports that ascertain this hypothesis.

2. Materials and Experimental Procedures

  • EDS analysis were performed at an accelerating voltage of 15 keV, using conventional ZAF correction procedure included in the EDAXPegasus software.
  • Samples of Shapal!-M and of AISI 304 stainless steel with 12-mm length were brazed for shear testing.

3. Results and Discussion

  • Typical microstructures of the interfaces obtained after joining at the different processing temperatures tested in this investigation are shown in Fig.
  • The detection of (Ag), (Cu), and Cu7In3 phases at the center of the interface is in agreement with the Ag-Cu-In vertical section shown in Fig. 4, which indicates that these phases may coexist in equilibrium.
  • Therefore, Ti-rich layer should be mainly 674—Volume 21(5) May 2012 Journal of Materials Engineering and Performance composed of TiN and may essentially result from the reaction with AlN, since Al was detected at the interface, while TiB2 was not identified.
  • Therefore, these are the critical parts of the joining: at the interface, crack nucleation and propagation should be eased at brittle TiN layer; cracks that eventually penetrate into the adjoining SM sample will cause disastrous failure of the joints.

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Active Metal Brazing of Machinable Aluminum
Nitride-Based Ceramic to Stainless Steel
Anı
´
bal Guedes and Ana Maria Pires Pinto
(Submitted September 29, 2011; in revised form December 14, 2011)
Shapal!-M machinable AlN-based ceramic and AISI 304 stainless steel were joined by active metal
brazing, at 750, 800, and 850 !C, with a dwell stage of 10 min at the processing temperature, using a 59Ag-
27.25Cu-12.5In-1.25Ti (wt.%) filler foil. The influences of temperature on the microstructural features of
brazed interfaces and on the shear strength of joints were assessed. The interfacial microstructures were
analyzed by scanning electron microscopy (SEM), and the composition of the phases detected at the
interfaces was evaluated by energy dispersive X-ray spectroscopy (EDS). The fracture surfaces of joints
were analyzed by SEM, EDS, and GIXRD (Grazing Incidence X-Ray Diffraction). Reaction between the
liquid braze and both base materials led to the formation of a Ti-rich layer, adjacent to each base material.
Between the Ti-rich layers, the interfaces consist of a (Ag) solid-solution matrix, where coarse (Cu) particles
and either Cu-In or Cu-In-Ti and Cu-Ti intermetallics phases are dispersed. The stronger joints, with shear
strength of 220 ± 32 MPa, were produced after brazing at 800 !C. Fracture of joints occurred preferen-
tially not only through the ceramic sample but also across the adjoining TiN layer, independent of the
brazing temperature.
Keywords brazing, mechanical testing, stainless steels, structural
ceramics
1. Introduction
Aluminum nitride (AlN) exhibits, among ceramics, a unique
combination of properties such as high thermal conductivity, high
electrical resistivity, low coefficient of thermal expansion, low
dielectric constant (Ref 1), large band gap, good thermal shock
resistance, and excellent corrosion resistance to plasma and
halogen gases (Ref 1, 2). Applications of AlN include electronic
substrates and packaging, high-frequency acoustic wave devices,
light-emitting diodes, and wide band gap semiconductors (Ref 1).
A new promising application of AlN is as a biosensing film for
use in wireless technology for monitoring cell, since it performs
effectively in biosensing and biophysical detection (Ref 3). AlN
is also reported to be an efficient material for nuclear applications
(Ref 4, 5). However, like other ceramics, AlN is intrinsically
brittle and thus, production of AlN components with intricate
shape is problematic. In addition, the low bending strength of
AlN hinders its application as a structural material. Shapal!-M
(Goodfellow, United Kingdom) is a machinable AlN-based
ceramic with a bending strength of almost 300 MPa, which is
comparable to that of alumina, with the advantage of possessing a
five-time higher thermal conductivity. The machinability and
strength of Shapal!-M enable its prospective use in structural
applications; this will inevitably require the processing of joints
between Shapal!-M and other materials. For instance, as AlN
(Ref 6), the joining of Shapal!-M to stainless steels may be
required for thermomechanical applications. Therefore, it is most
important to assess the possibility of producing sound Shapal!-M
joints that present adequate mechanical properties. Brazing
(Ref 6-8), active metal brazing (Ref 6, 9-11), copper direct
bonding (Ref 6, 12-14), transient liquid phase bonding (Ref 15),
and diffusion bonding (Ref 7, 16, 17), have been reported to be
adequate techniques to join AlN. These joining routes may be
suitable to produce Shapal!-M joints but, to our best knowledge,
there are no reports that ascertain this hypothesis.
The main aims of the study reported in this article are to
assess the suitability of using Incusil-ABA (MTC Wesgo
Metals, United States), which is an active brazing alloy based
on Ag-Cu eutectic alloyed with In and Ti, as filler for joining
Shapal!-M to AISI 304 stainless steel (Goodfellow, United
Kingdom) and to determine the influence of the processing
temperature upon the microstructural features of the interfaces
and on the mechanical strength of joints.
2. Materials and Experimental Procedures
Samples of Shapal!-M (70AlN-30BN, wt.%) and of AISI
304 stainless steel (Fe-18Cr-10Ni-0.04C, wt.%), with 10 and
12.7 mm in diameter, respectively, were cut with a low-speed
diamond saw to a thickness of 5 mm and then ground with SiC
emery paper down to 4000 grade. A 100-lm-thick foil of
Incusil-ABA (59Ag-27.25Cu-12.5In-1.25Ti, wt.%) was used as
This article is an invited submission to JMEP selected from
presentations at the Symposia ‘Wetting, soldering and brazing’ and
‘Diffusion bonding and characterization’ belonging to the Topic
‘Joining’ at the European Congress and Exhibition on Advanced
Materials and Processes (EUROMAT 2011), held September 12-15,
2011, in Montpellier, France, and has been expanded from the original
presentation.
Anı´bal Guedes and Ana Maria Pires Pinto, Department of
Mechanical Engineering, University of Minho, CT2M, Campus de
Azure´m, Guimara˜es 4800-058, Portugal. Contact e-mails: aguedes@
dem.uminho.pt and anapinto@dem.uminho.pt.
JMEPEG (2012) 21:671–677 "ASM International
DOI: 10.1007/s11665-012-0122-6 1059-9495/$19.00
Journal of Materials Engineering and Performance Volume 21(5) May 2012—671

filler. The foil was cut into disks with the same diameter as that
of Shapal!-M samples. Before brazing, all materials were
cleaned in acetone with ultrasonic agitation and dried in air. A
contact pressure of 2.9 x 10
4
Pa was applied, by means of a
stainless steel mass, to the brazing assemblage that consisted of
a Shapal!-M/Incusil-ABA/AISI 304 stainless steel sandwich.
The assemblage was inserted into the chamber of an electrical
furnace that was evacuated to a vacuum level that remained
greater than 10
!2
Pa during the entire brazing thermal cycle.
Brazing was performed at 750, 800, and 850 #C with a 10-min
dwelling stage; the heating and cooling rates were set to
3 #C min
!1
by a temperature controller.
Joints for microstructural and chemical characterization
were cross-sectioned perpendicularly to the interface, cold
mounted in epoxy resin, and then prepared according to
standard metallographic techniques. The microstructure and the
chemical composition of the interfaces were analyzed on a FEI
Nova 200 scanning electron microscope, equipped with an
EDAX-Pegasus energy dispersive spectrometer. EDS analysis
were performed at an accelerating voltage of 15 keV, using
conventional ZAF correction procedure included in the EDAX-
Pegasus software.
Samples of Shapal!-M and of AISI 304 stainless steel with
12-mm length were brazed for shear testing. Shear testing was
conducted at room temperature with a crosshead speed of
5 mm min
!1
. At least, five samples were tested for each brazing
temperature. Additional details on the shear test apparatus are
given elsewhere (Ref 18). The fracture surfaces were examined
by SEM, EDS, and GIXRD (Grazing Incidence X-Ray Diffrac-
tion) performed at 40 kV and 40 mA, using Cu Ka radiation.
For the sake of convenience, Shapal!-M and AISI 304
stainless steel will be referred hereafter as SM and SS, respectively.
3. Results and Discussion
Typical microstructures of the interfaces obtained after
joining at the different processing temperatures tested in this
investigation are shown in Fig. 1. All brazing temperatures
induced the formation of interfaces with no apparent porosity
and free of cracks. The interfaces could be divided into three
different zones: the central zone, and the thin reaction layers
formed near the base materials—one adjacently to SM and the
other contiguously to the SS sample. The reaction layers are
barely detectable after brazing at 750 #C, since they are
extremely thin and not continuous. Near SM, the extension of
reaction layer, which is at the most 4 lm thick, slightly
increases with the increment in brazing temperature. However,
the thickness of reaction layer formed contiguously to SS
remained less than 1 lm for all brazing temperatures. The
extension of the interface decreases as the brazing temperature
is incremented. The interfaces are about 85, 55, and 25 lm
thick, for brazing at 750, 800, and 850 #C, respectively, as
observed in Fig. 1. It should be noted that due to the open end
configuration of joints, the liquid filler is free to flow out of the
joint gap. In addition to that, the contact pressure applied to
the joining assemblage may also enhance overflowing. Since
the fluidity of molten filler increases as the brazing temperature
is incremented, a higher volume fraction of molten braze will
be lost causing the overall extension of the interface to
decrease. A similar evolution of the width of the interface was
reported when Incusil-ABA was used to produce titanium/steel
joints (Ref 19); the configuration of joints and the brazing
temperatures were the same as those used in the present study.
By the analysis of Fig. 2 and 3, where the elemental
distributions across the interface are presented for the two
limiting temperatures tested, it can be concluded that there was
little interdiffusion between the base materials and the braze
alloy. In addition, it can be observed that Ti atoms tend to
migrate toward the vicinity of both base materials. The
diffusivity of Ti increases with temperature increment, and
thus, the central zone of the interface becomes progressively
depleted in Ti as the brazing temperature is raised. Figure 3 is
Fig. 1 Backscattered electron images (BEIs) of the interfaces after
joining at different temperatures
672—Volume 21(5) May 2012 Journal of Materials Engineering and Performance

particularly elucidative regarding the segregation of Ti and the
formation of Ti-rich reaction layers adjacently to both SM and
SS samples.
Semi-quantitative SEM/EDS analysis was used in conjunc-
tion with ternary phase diagrams to evaluate the nature of the
phases detected at the central zone of the interfaces. Results of
EDS analysis performed on several phases detected after
brazing at 750 #C are presented in Fig. 2. As observed in the
figure, the central zone of the interface is composed of a
mixture consisting of a white phase and several gray phases.
The white phase is rich in Ag and In and should consist of (Ag)
solid solution, since its composition lies on the (Ag) single-
phase field of the Ag-Cu-In isothermal section presented in
Fig. 4. The gray phase is (Cu) solid solution and the dark-gray
phase, which is indicated by an arrow in Fig. 2, should consist
of CuTi intermetallic compound. The light-gray phase is
predominantly composed of Cu, Ti, and In. The Cu-In-Ti phase
diagram is still to be established, and the only known
compound belonging to this system is Cu
2
InTi (Ref 20). The
phase detected in the present investigation is richer in Cu, and
poorer in In than Cu
2
InTi, since its stoichiometry is, approx-
imately, Cu
2.5
In
0.8
Ti. However, the interactions of Cu-rich
zones located below and around the light-gray phase may
induce slightly misleading EDS results. Thus, the light-gray
phase may be less rich in Cu than is indicated by EDS analysis,
and therefore, its composition may be in fact closer to that of
Cu
2
InTi.
For joining either at 800 and 850 #C, the central zone of the
interface consists mainly of a mixture of (Ag) and (Cu) solid
solutions and Cu-In-rich phase; no Cu-In-Ti phase was
detected. The composition of the Cu-In-rich phase (7.4Ag-
64.2Cu-26.9In, at.%) lies near the Cu
7
In
3
single-phase field on
the Ag-Cu-In isothermal section presented in Fig. 4, where it is
Fig. 2 X-ray elemental line scan profiles across the interface and
chemical compositions of phases detected after brazing at 750 #C
Fig. 3 X-ray diffraction elemental maps of the interface after braz-
ing at 850 #C
Journal of Materials Engineering and Performance Volume 21(5) May 2012—673

referred as the light-gray phase. The detection of (Ag), (Cu),
and Cu
7
In
3
phases at the center of the interface is in agreement
with the Ag-Cu-In vertical section shown in Fig. 4 , which
indicates that these phases may coexist in equilibrium.
The bridging between the central zone of the interface and
either SM or SS sample is promoted by the formation of a thin
Ti-rich layer. The formation of a thin Ti-rich layer adjacently to
aluminum nitride after joining either by active metal brazing
(Ref 6, 7, 9, 10) or by transient liquid phase bonding (Ref 15),
using Ti-activated brazing alloys, is reported in several studies.
TiN was found to be the main phase of the reaction layer
detected near aluminum nitride, and it would result from the
following reaction:
AlN þ Ti , Al þ TiNðDG
0
T
¼!9835 ! 23:4T ; J mol
!1
Þ
Data collected from (Ref 21) were used to calculate the
standard Gibbs free energy variation (DG
T
0
) of the reaction. For
all brazing temperatures tested in this investigation, the reaction
is, for standard conditions, thermodynamically favorable:
!33.8, !35.0, and !36.2 kJ mol
!1
at 750, 800, and 850 #C,
respectively; these values are in good agreement with those
reported by Dezellus et al. (Ref 15). Thus, the reaction of AlN
from SM with Ti atoms that are dissolved into the melt may
induce the formation of a TiN layer, and the dissolution of Al
atoms into the remaining liquid filler. It should be noted that Ti-
rich layer is often reported to be composed of two sublayers: a
layer of TiN (Ref 22) or TiN
0.67
(Ref 15) formed contiguously
to the ceramic, and another layer mainly consisting of a
quaternary phase (Ti, Cu, Al)
6
N (Ref 15, 22) adjacent to it. In
the present investigation, when brazing is carried out at 850 #C,
Ti-rich layer occasionally seems to present a layered morphol-
ogy (see Fig. 3). However, it was impossible to assess the
composition of each sublayer, since they were less than 1 lm
thick wherever this apparent morphology was observed at the
interface.
SM is composed of AlN (70%, wt.%) and of BN (30%,
wt.%). Therefore, interfacial reaction products may also result
from the reaction of the liquid braze with BN. Ding et al. (Ref
23) studied the joining of cubic BN by active metal brazing,
using a Ti-activated filler at temperatures ranging between 880
and 920 #C. Those authors reported that the reaction between
the liquid braze and cubic BN induced the formation of TiN and
TiB
2
at the reaction layer detected near the ceramic. Further,
according to the same authors (Ref 24), the formation TiN and
TiB
2
may result from following reaction:
BN þ
3
2
Ti , TiN þ
1
2
TiB
2
This reaction is thermodynamically viable at 600, 800, and
950 #C, since the corresponding DG
T
0
values are !235.34,
!241.19, and !230.73 kJ mol
!1
(Ref 24).
The results of Ding et al. (Ref 23, 24) suggest that in the
present investigation, BN may have reacted with Ti from the
liquid braze, promoting the formation of reaction products near
SM sample, since the brazing temperatures tested were in the
range of 600-950 #C. Considering these studies (Ref 15, 22-
24), TiN phase would result from the reaction between Ti and
either AlN or BN crystals, while TiB
2
would only result from
the reaction between Ti and BN. As will be discussed latter,
contrarily to TiB
2
, the formation of TiN at the interface was
confirmed by GIXRD analysis performed on the fracture
surfaces of the joints. Therefore, Ti-rich layer should be mainly
Fig. 4 Isothermal sections of the Ag-Cu-Ti and Ag-Cu-In dia-
grams, where the compositional plots of some of the reaction prod-
ucts are marked, and 20 wt.% In vertical section of the Ag-Cu-In
diagram. Adapted from Ref 20
674—Volume 21(5) May 2012 Journal of Materials Engineering and Performance

composed of TiN and may essentially result from the reaction
with AlN, since Al was detected at the interface, while TiB
2
was not identified.
Regarding the nature of Ti-rich layer located near SS,
Fe35Cr13Ni3Ti7 and FeTi phases were detected by Kar et al.
(Ref 25) after joining AISI 304 to Al
2
O
3
by active metal
brazing. Joining was performed at higher temperatures (900 and
1000 #C) than those tested in the present investigation, and the
active brazing alloy used was richer in Ti (4%, wt.%).
Consequently, higher reaction rate between the liquid braze
and AISI 304 was achieved, and the formation of thicker
(12 lm) Ti-rich layer near the stainless steel sample was
observed. In the present investigation, Ti-rich layer near SS is
less than 1 lm thick; the formation of Fe35Cr13Ni3Ti7 and/or
FeTi intermetallic was impossible to confirm, but it could not
be discarded.
It is well established that the strengths of metal/ceramic
joints tend to increase as the reactions products formed near the
base materials (essentially those formed near the ceramic) grow
and integrate into one of more reaction layers (Ref 26).
However, these reaction layers are usually composed of
extremely hard and brittle phases, and their excessive
thickening will cause degradation of the mechanical properties
of the joints. This is primarily because these phases have little
or no capacity of accommodating the residual stresses that
derive predominantly from mismatches between the coeffi-
cients of thermal expansion (CTE) of the ceramic and metal
samples. Thus, after reaching the maximum strength, the joints
weaken because the interface becomes gradually more brittle as
the volume fraction of hard reaction products increases.
The strength of joints obtained in the present investigation
follows a similar trend. When joints are processed at 750 #C,
the shear strength is only 148 ± 40 MPa, probably because the
layer composed mainly of TiN formed contiguously to SM is
still too thin and discontinuous to maximize the bonding
strength. The maximum shear strength (220 ± 32 MPa) is
obtained after brazing at 800 #C. At this processing tempera-
ture, TiN layer near SM is thick and continuous enough to
promote the formation of stronger joints. In addition, the center
of the interface still preserves a high capacity of buffering CTE
mismatches (according to the Goodfellow!s catalogue, CTE of
SM and SS at 20 # C are, 5.2 9 10
!6
and 18 9 10
!6
K
!1
,
respectively). After brazing at 850 #C, the flowing of the liquid
braze out of the joint gap induces a substantial decrease of the
volume fraction of soft and ductile phases, like (Ag) solid
solution, which is mainly detected at the center of the interface,
in comparison to the interfaces produced at lower temperatures,
as can be inferred by the analysis of Fig. 1. Consequently, the
interface becomes more brittle and loses part of its capacity in
accommodating CTE mismatches. Thus, after joining at
850 #C, the shear strength of joints (168 ± 47 MPa) decreases,
in comparison to those processed at 800 #C.
In spite of the differences between the strength of joints
produced under different brazing temperatures, the fracture
mode remained the same. The joints fractured partially across
the interface and partially throughout the SM sample, which
broke into several pieces. The fracture surface of SM samples
was partially covered with a thin black layer of reaction
products, while the SS side of the fracture surface was covered
by a thicker layer with small fragments of SM still joined to it.
Figure 5 shows a fractograph of the SM side of the joints; the
bulk of SM is observed in zone marked as Z1, whereas zone
marked as Z2 is partially covered by reaction products. Thus,
part of the interface is included on the ceramic side of the
fracture surface. The fractograph of the SS side of the joints is
presented in Fig. 6. As observed in the figure, there are
fragments of SM (Z1) attached to the SS sample, which is
partially covered by reaction products (Z2). In addition, part of
braze alloy (Z3) that has spread out of the joint gap is also
observed at the periphery of the fracture surface. These
observations show that fracture occurred partially across the
interface and partially throughout the SM sample. GIXRD
spectra of the fracture surfaces presented in Fig. 7 confirm the
presence of AlN on the SM side and of AlN and TiN phases on
the SS side. It should be noted that AlN and TiN present 2h
peaks very close to each other around 59#, and so it is very
difficult to differentiate them. On the fracture surface of SM,
this diffraction peak was assumed to result only from AlN-
Fig. 5 BEI of the fracture surface on the AlN side of the joints
after brazing at 800 #C
Fig. 6 BEI of the fracture surface on the SS side of the joints after
brazing at 800 #C
Journal of Materials Engineering and Performance Volume 21(5) May 2012—675

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01 Oct 1995
TL;DR: The largest collection of ternary phase diagrams and related crystal structure data ever assembled can be found in this 10 volume set.
Abstract: The largest collection of ternary phase diagrams and related crystal structure data ever assembled can be found in this 10 volume set. Some features of the reference set: 18,000 published diagrams Exhaustive bibliographies by Dr. Prince Includes diagrams from the compilations from the International Programme for Alloy Phase Diagrams 7,380 ternary systems ternary phase diagrams for 3,317 alloy systems Crystallographic data on 7,050 systems Includes liquidus projections, isotherms, isopleths, and pseudobinaries All diagrams were redrawn to uniform standards for easy use and comparison Temperatures given in degrees C and all compositions given in atomic relative orientation of elements is standardized (no rotating or mirroring needed) Angle between composition scales in all horizontal views (projections and isothermal sections) standardized at 60 degrees More than 43,000 citations of included literature most composition scales are identical within a diagram Boundary regions adjusted to critically evaluated binary diagrams

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TL;DR: In this article, it was found that bonds formed by brazing with aluminium at 1000 °C could have shear strengths as great as 60MPa, which suggested that good brazings systems could be developed.
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166 citations

Journal ArticleDOI
TL;DR: In this article, the successful production of reliably strong joints by diffusion bonding and brazing with reactive filler metals is discussed, and comments on the influence of process and parameters such as temperature, environment and ceramic surface preparation on the microstructure, mechanical properties and high temperature stability of interfaces.

46 citations

Journal ArticleDOI
TL;DR: In this paper, an attempt was made to simultaneously correlate the microstructure, mechanical properties, and brazing temperature of steel to titanium brazed joint, which was conducted by means of silver-based filler (Incusil ABA) at a temperature range of 650-850°C for 15min in a high vacuum furnace.

46 citations

Journal ArticleDOI
TL;DR: In this paper, different methods of joining, successfully used for alumina, solid state bonding, liquid-state bonding and direct copper bonding (DCB, brazing), can be used for AlN.
Abstract: The use of aluminium nitride in a wide range of applications depends on the capability to form strong AlN/AlN and AlN/metals (or alloys) joints. It has been shown that the different methods of joining, successfully used for alumina, solid-state bonding, liquid-state bonding and direct copper bonding (DCB, brazing), can be used for AlN. An optimisation of the different bonding parameters is required to obtain strong bonds. The influence of oxygen, nitrogen and the role of reactions products have been outlined.

43 citations

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Q1. What have the authors contributed in "Active metal brazing of machinable aluminum nitride-based ceramic to stainless steel" ?

Between the Ti-rich layers, the interfaces consist of a ( Ag ) solid-solution matrix, where coarse ( Cu ) particles and either Cu-In or Cu-In-Ti and Cu-Ti intermetallics phases are dispersed.