Indium/Silver Alloy Plate (In97/Ag 3) Description
The Indium/Silver Alloy Plate
(In97/Ag3) is a specialized material
composed of 97% indium and 3% silver, engineered to combine the unique
properties of both metals. With a low melting point of approximately 157°C, it
retains excellent ductility and cold-forming capabilities, allowing it to be
shaped into thin, uniform plates or foils without cracking. This alloy exhibits
high electrical conductivity (3.3×10⁶ S/m) and thermal conductivity (~80
W/m·K), making it ideal for applications requiring efficient heat dissipation
and reliable electrical interconnects, such as thermal interface materials (TIMs)
in high-power electronics or solder-free bonding in flexible circuits.
Its oxidation resistance and
minimal formation of brittle intermetallic compounds ensure long-term stability
in harsh environments, including cryogenic systems and vacuum-sealed devices.
The alloy’s ultra-low vapor pressure and compatibility with hermetic sealing
processes make it suitable for aerospace components, satellite shielding, and
medical device packaging. The spooled plate format enables continuous
processing in automated production lines, reducing waste and enhancing
efficiency. Additionally, the inclusion of silver enhances mechanical strength
while preserving indium’s intrinsic softness, achieving a balance between
durability and conformability for precision applications like MEMS
(Micro-Electro-Mechanical Systems) and optoelectronic packaging. This alloy’s
versatility and reliability underscore its importance in advanced engineering
and miniaturized electronic systems.
Indium/Silver Alloy Plate (In97/Ag3) Applications
1. Semiconductor Packaging:
Thermal Interface Materials (TIMs): Acts as a conformable,
high-conductivity layer between heat-generating components (e.g., CPUs, GPUs)
and heat sinks, reducing thermal resistance in high-power electronics.
Die Attach: Bonds delicate semiconductor dies to substrates
without thermal stress, leveraging its low melting point and ductility.
2. Flexible Electronics:
Solder-Free Interconnects: Forms cold-welded joints in
flexible circuits, wearable devices, and foldable displays, ensuring durability
under repeated bending.
3. Cryogenic Systems:
Seals and Gaskets: Provides leak-tight seals in cryogenic
pumps, superconducting magnets, and space satellite components, maintaining
integrity at ultra-low temperatures.
4. Aerospace & Defense:
Vacuum-Sealed Components: Used in radar systems, infrared
detectors, and vacuum tubes due to its ultra-low outgassing and oxidation
resistance.
Radiation Shielding: Enhances protection in satellite
components by combining indium’s neutron absorption and silver’s EMI shielding
properties.
5. Medical Devices:
Hermetic Encapsulation: Seals implantable devices (e.g.,
pacemakers) against moisture and bodily fluids, ensuring long-term
biocompatibility.
6. Optoelectronics:
LED/Laser Packaging: Serves as a thermal buffer in
high-brightness LEDs and laser diodes, preventing overheating and prolonging
lifespan.
7. Automotive Electronics:
Power Module Bonding: Joins IGBTs and SiC modules in
electric vehicles (EVs), ensuring efficient heat dissipation under high-current
loads.
Indium/Silver Alloy Plate (In97/Ag3) Packaging
Our products are packaged in customized cartons of various
sizes based on the material dimensions. Small items are securely packed in PP
boxes, while larger items are placed in custom wooden crates. We ensure strict
adherence to packaging customization and the use of appropriate cushioning
materials to provide optimal protection during transportation.

Packaging: Carton, Wooden Box, or Customized.
Kindly review the packaging
details provided for your reference.
Manufacturing Process
1. Testing Method
(1) Chemical Composition Analysis - Verified using techniques
such as GDMS or XRF to ensure compliance with purity requirements.
(2) Mechanical Properties Testing - Includes tensile strength,
yield strength, and elongation tests to assess material performance.
(3) Dimensional Inspection - Measures thickness, width, and
length to ensure adherence to specified tolerances.
(4) Surface Quality Inspection - Checks for defects such as
scratches, cracks, or inclusions through visual and ultrasonic examination.
(5) Hardness Testing - Determines material hardness to confirm
uniformity and mechanical reliability.
Please refer to the SAM testing procedures for detailed information.
Indium/Silver Alloy Plate (In97/Ag3) FAQs
Q1. What is In97/Ag3 Alloy Plate?
In97/Ag3 is a ductile, low-melting-point alloy composed of
97% indium (In) and 3% silver (Ag), supplied in a continuous spooled plate
format for automated manufacturing.
Q2. How is the spooled plate format advantageous?
Automated processing: Enables continuous, high-speed
production (e.g., roll-to-roll manufacturing).
Reduced waste: Pre-cut widths/thicknesses (e.g., 0.1-1.0 mm)
minimize material loss.
Q3. What are its limitations?
Low mechanical strength: Not suitable for load-bearing
applications.
Cost: Higher price than tin-based solders due to indium’s
scarcity.
Performance Comparison Table with Competitive Products
Property
|
In97/Ag3
|
Pure Indium (In99.99)
|
In90/Ag10
|
Pure Silver
Ag: 99.99
|
Melting Point (°C)
|
157
|
156
|
143-160
|
961
|
Electrical Conductivity (%IACS)
|
86
|
21
|
75
|
105
|
Thermal Conductivity (W/m·K)
|
80
|
82
|
70
|
429
|
Elongation (%)
|
>80
|
>90
|
50-70
|
45
|
Tensile Strength (MPa)
|
10-15
|
4-10
|
20-30
|
125-170
|
Oxidation Resistance
|
High
|
Low
|
Moderate
|
High
|
Thermal Expansion Coefficient (ppm/°C)
|
25
|
33
|
24
|
19.7
|
Typical Thickness (mm)
|
0.1-1.0
|
0.1-2.0
|
0.2-1.5
|
0.05-0.3 (foil)
|
Key Application
|
Cryogenic seals, TIMs
|
Low-stress gaskets
|
Aerospace bonding
|
High-current interconnects
|
Related Information
1. Preparation and pretreatment of
raw materials
Firstly, high-purity (≥99.99%) Indium (In) and Silver (Ag) metal lumps are
selected, which are accurately weighed according to the mass ratio of 97%
Indium to 3% Silver. The metal raw materials need to be pre-cleaned to remove
surface oxides and contaminants, followed by drying under the protection of
inert gas (e.g., argon) to avoid oxidation during the subsequent melting
process.
2. Vacuum melting and alloying
Pre-treated indium and silver are
placed in a vacuum induction melting furnace and heated under vacuum or inert
atmosphere to above the melting point of indium (about 160°C), and then
continue to raise the temperature to the melting point of silver (961°C) after
the indium is completely melted, and then ensure that the silver is uniformly
dissolved in indium by electromagnetic stirring to form a homogeneous In97/Ag3
molten alloy. At this stage, the temperature gradient and stirring time should
be strictly controlled to avoid compositional segregation.
3. Casting and Primary Rolling
The molten alloy is rapidly cast
into flat ingots or thick plates through water-cooled copper molds to refine
the grain structure and reduce shrinkage defects by rapid cooling (cooling rate
>50°C/s). Subsequently, the ingot is preheated to 80-100°C and gradually
thinned to the target thickness (e.g., 0.1-1.0 mm) by a multi-pass hot rolling
process, with the temperature maintained during the rolling process to preserve
the ductility of the alloy and prevent cold rolling cracking.
4. Precision cold rolling and
annealing
After hot rolling, the plates are
cold rolled to further control thickness tolerances (±0.01 mm) and surface
finish. During the cold rolling process, the deformation amount per pass is
between 10% and 20% to avoid excessive work hardening. Subsequently, intermittent
annealing (150-200°C, inert atmosphere) is carried out to remove internal
stresses and restore plasticity to ensure subsequent processability.
5. Surface treatment and quality
inspection
The rolled plates are
electrolytically polished or chemically cleaned to remove surface oxidization
and rolling oil residues to obtain a bright, defect-free surface. Composition
uniformity is detected by X-ray fluorescence spectroscopy (XRF) to ensure that
the silver content is accurately controlled at 3±0.1%. Meanwhile, ultrasonic
flaw detector is utilized to check the internal pores or cracks to ensure
material densification.