S4J38A Sealing Alloy Manufacturer | Fe-Ni-Co-Cu Controlled Expansion Alloy

Description

S4J38A FeNiCoCu sealing alloy delivers precisely controlled CTE for ceramic-to-metal and glass sealing. Ideal for hermetic packages, semiconductor devices, aerospace, and medical electronics. MTC EN 10204 3.1 available.

S4J38A Fe-Ni-Co-Cu Controlled Expansion Sealing Alloy

S4J38A controlled expansion sealing alloy is a specialized Fe-Ni-Co-Cu alloy designed for applications requiring controlled thermal expansion and reliable metal-to-glass or metal-to-ceramic sealing.

The alloy is intended for precision sealing structures where thermal expansion compatibility between the metal and the sealing material is critical. Typical application areas include ceramic-to-metal sealing, glass-to-metal sealing, hermetic electronic packaging, semiconductor components, aerospace electronics and medical electronic devices.

Hefei Ke Ningman New Energy Materials Technology Co., Ltd. supplies S4J38A sealing alloy according to application requirements, product dimensions, material specifications and customer drawings.

Material designation note: S4J38A should be specified according to the applicable manufacturer or customer specification. It should not automatically be treated as equivalent to the standardized 4J38 low-expansion machinable alloy unless such equivalence has been verified by technical documentation.

S4J38A Sealing Alloy at a Glance

Chemical composition, CTE and other physical properties should be confirmed against the applicable S4J38A technical specification or material certificate.

What Is S4J38A Sealing Alloy?

S4J38A is a Fe-Ni-Co-Cu controlled expansion sealing alloy developed for precision applications where the thermal expansion behavior of a metallic component must be compatible with glass or ceramic materials.

In a hermetic sealing assembly, the metal and glass or ceramic experience dimensional changes during heating and cooling.

The basic engineering relationship is:

Metal CTE ↔ Glass / Ceramic CTE ↔ Sealing Temperature ↔ Cooling Process

If the thermal expansion mismatch is too large, excessive residual stress can develop at the sealing interface.

This can result in:

• Glass cracking

• Ceramic cracking

• Interface separation

• Leakage

• Loss of hermeticity

• Dimensional deformation

• Reduced thermal-cycle reliability

For this reason, S4J38A should be selected according to the actual glass or ceramic material, sealing temperature and component geometry.

Why Use a Controlled Expansion Sealing Alloy?

Controlled expansion alloys are used when ordinary steel or conventional stainless steel cannot provide the required thermal expansion compatibility.

The main advantages of a properly selected controlled expansion sealing alloy include:

Controlled Thermal Expansion

The alloy is engineered to provide predictable dimensional change over the required temperature range.

Improved Sealing Compatibility

A suitable thermal expansion relationship between the metal and glass or ceramic can help reduce residual stress at the sealing interface.

Hermetic Packaging Potential

Controlled expansion alloys are widely used in engineering designs where reliable gas-tight or moisture-resistant sealing is required.

Dimensional Stability

Controlled thermal expansion is particularly important in precision electronic and semiconductor components that experience repeated thermal cycles.

Application Flexibility

Depending on the final material specification, product geometry and sealing process, S4J38A can be evaluated for both glass and ceramic sealing applications.

S4J38A Thermal Expansion and CTE

The coefficient of thermal expansion (CTE) is one of the most important parameters when selecting a sealing alloy.

For S4J38A, the required CTE should be specified according to the customer's actual application rather than relying on a single nominal value.

Important parameters include:

• CTE over the required temperature range

• Glass or ceramic CTE

• Sealing temperature

• Operating temperature

• Heating rate

• Cooling rate

• Thermal cycling conditions

• Material heat-treatment condition

A typical material-selection process is:

S4J38A CTE → Sealing Material CTE → Thermal Expansion Curve → Sealing Temperature → Thermal Stress Evaluation

For critical applications, customers should provide the target CTE range and temperature interval.

We can then evaluate the required material specification and testing requirements.

S4J38A for Ceramic-to-Metal Sealing

Ceramic-to-metal sealing is commonly used where high electrical insulation, temperature resistance and hermeticity are required.

A controlled expansion alloy can help reduce the thermal mismatch between the metallic component and ceramic material during thermal processing.

Potential applications include:

• Ceramic feedthroughs

• Hermetic electrical connectors

• Semiconductor packages

• Ceramic electronic packages

• High-reliability terminals

• Aerospace electronic components

• Medical electronic components

The final alloy selection should consider the exact ceramic grade.

Common engineering parameters include:

• Ceramic composition

• Ceramic CTE

• Sealing temperature

• Metallization system

• Metal thickness

• Joint geometry

• Operating temperature

• Thermal cycling requirements

S4J38A for Glass-to-Metal Sealing

Glass-to-metal sealing requires careful matching of the thermal expansion characteristics of the glass and metal.

S4J38A can be evaluated for glass sealing applications where a controlled-expansion Fe-Ni-Co-Cu alloy is required.

The sealing process may involve:

Metal Preparation → Cleaning → Surface Conditioning → Glass Assembly → Heating → Sealing → Controlled Cooling → Leak Testing

Important process parameters may include:

• Glass composition

• Glass CTE

• Glass transition temperature

• Softening temperature

• Sealing temperature

• Metal surface condition

• Atmosphere

• Heating rate

• Cooling rate

• Joint geometry

The alloy should therefore be selected together with the actual glass rather than selected solely according to the alloy name.

S4J38A for Hermetic Electronic Packaging

Hermetic electronic packaging requires reliable protection against moisture, gases and environmental contamination.

Controlled expansion sealing alloys can be used in metal-to-glass or metal-to-ceramic interfaces within hermetic packages.

Potential applications include:

• Semiconductor packages

• Electronic housings

• Hermetic connectors

• Electrical feedthroughs

• Sensor packages

• Microwave packages

• High-reliability electronic components

The selection of S4J38A should be based on the complete package design and sealing material.

S4J38A for Semiconductor Applications

Semiconductor packages often combine metals, ceramics, glass and other materials with different thermal expansion characteristics.

During manufacturing and operation, these materials can experience repeated temperature changes.

A suitable controlled expansion alloy can help engineers manage thermal mismatch at critical interfaces.

Potential applications include:

• Semiconductor hermetic packages

• Ceramic semiconductor packages

• Electrical feedthroughs

• Sealed terminals

• High-reliability electronic housings

• Sensor packages

For semiconductor applications, customers should provide the ceramic or glass grade, target CTE, operating temperature and required package geometry.

S4J38A for Aerospace Electronics

Aerospace electronic components may experience:

• Large temperature changes

• Thermal cycling

• Vibration

• Pressure variations

• Long service periods

• Strict reliability requirements

For these applications, the sealing alloy must be evaluated together with the glass or ceramic sealing material and the complete component design.

S4J38A can be considered for selected aerospace electronic sealing structures where controlled expansion is required.

S4J38A for Medical Electronics

Hermetically sealed medical electronic components require reliable protection of internal electronics from the external environment.

Potential applications include:

• Hermetic medical electronic packages

• Sensor housings

• Electrical feedthroughs

• Implantable-device components

• Precision medical electronics

Material selection should consider:

• Biocompatibility requirements where applicable

• Hermeticity

• Thermal cycling

• Corrosion environment

• Sealing material

• Component geometry

• Regulatory requirements

The final material specification should be agreed according to the actual application.

S4J38A Product Forms

Depending on the required dimensions and production process, S4J38A may be supplied in customized forms such as:

• Sheet

• Strip

• Wire

• Rod

• Bar

• Tube

• Foil

• Precision-cut material

• Stamped components

• Customized sealing components

Available dimensions depend on the production route and customer specification.

For precision applications, customers should provide:

• Thickness

• Width

• Diameter

• Length

• Tolerance

• Surface condition

• Heat-treatment condition

• Quantity

• Drawing

S4J38A Manufacturing Process

Precision controlled-expansion alloys require careful control of both chemical composition and processing condition.

A typical manufacturing route may include:

1. Raw Material Selection

Raw materials are selected according to the required Fe-Ni-Co-Cu alloy specification.

2. Melting and Alloying

Controlled melting is used to achieve the required chemical composition and material uniformity.

3. Homogenization

Thermal processing can be used to improve compositional and microstructural uniformity.

4. Hot Working

The alloy is processed into an intermediate form suitable for further manufacturing.

5. Cold Working

Rolling, drawing or other precision processes are used to achieve the required dimensions.

6. Intermediate Annealing

Annealing may be applied to control hardness, residual stress and workability.

7. Final Heat Treatment

The final material condition is controlled according to the required thermal expansion and application specification.

8. Surface Finishing

Surface treatment may include cleaning, grinding, polishing or other finishing processes according to the application.

9. Final Inspection

The finished product can be inspected for:

• Chemical composition

• Dimensions

• Surface quality

• Mechanical properties

• Thermal expansion characteristics

• Product condition

• Material traceability

S4J38A Quality Control

For hermetic sealing applications, material consistency is critical.

Our quality-control program can include:

Chemical Composition Testing

Chemical composition can be verified according to the agreed S4J38A specification.

Dimensional Inspection

Inspection may cover:

• Thickness

• Width

• Diameter

• Length

• Flatness

• Straightness

• Dimensional tolerance

Surface Inspection

Surface inspection can identify:

• Cracks

• Scratches

• Pitting

• Scale

• Oxidation

• Laminations

• Other visible defects

Thermal Expansion Testing

CTE testing can be performed over the temperature range specified by the customer.

The test temperature range should be clearly defined because CTE is temperature-dependent.

Mechanical Testing

Where required, testing may include:

• Tensile strength

• Elongation

• Yield strength

• Hardness

Material Traceability

Production batches can be linked to inspection records and material documentation according to order requirements.

S4J38A vs Other Controlled Expansion Sealing Alloys

Different sealing alloys are designed for different glass or ceramic systems.

This comparison is intended only as an initial material-selection guide.

The correct alloy should be selected according to the actual:

• Glass or ceramic CTE

• Sealing temperature

• Operating temperature

• Component geometry

• Hermeticity requirements

• Thermal cycling requirements

How to Select S4J38A Sealing Alloy

Before purchasing S4J38A, engineering and procurement teams should provide the following information.

1. Sealing Material

Provide the exact glass or ceramic grade.

2. CTE Requirement

Provide the required thermal expansion range and test temperature interval.

3. Sealing Temperature

Specify the actual processing temperature.

4. Operating Temperature

The service temperature may differ significantly from the sealing temperature.

5. Product Form

Specify whether you require:

• Wire

• Strip

• Sheet

• Rod

• Tube

• Foil

• Custom components

6. Dimensions and Tolerance

Provide the drawing or detailed dimensions.

7. Hermeticity Requirement

Specify the required leak rate and testing method where applicable.

8. Certification

Specify whether you require:

• Material certificate

• Chemical analysis

• CTE test report

• Mechanical test report

• Inspection report

• EN 10204 3.1 documentation

S4J38A Material Specification

Because S4J38A may be supplied according to a manufacturer-specific or customer-specific specification, the purchasing document should clearly define:

• Material designation

• Chemical composition

• CTE range

• Temperature range

• Product form

• Dimensions

• Tolerance

• Heat-treatment condition

• Surface condition

• Testing requirements

• Certification requirements

Do not rely on the alloy designation alone when purchasing precision sealing material.

For international procurement, a complete technical specification reduces the risk of receiving a materially different alloy under a similar commercial designation.

Important Note About S4J38A and 4J38

S4J38A should not automatically be considered equivalent to 4J38.

The standardized Chinese 4J38 designation is associated with a low-expansion, free-machining Fe-Ni-Se alloy, while the S4J38A product described on this page is identified as an Fe-Ni-Co-Cu controlled expansion sealing alloy.

If an equivalent standard grade is required, the equivalence should be confirmed through:

• Chemical composition

• CTE

• Heat-treatment condition

• Applicable standard

• Material certificate

• Customer specification

This distinction is important for engineering procurement and quality assurance.

Why Choose S4J38A from Greenergy Materials?

Hefei Ke Ningman New Energy Materials Technology Co., Ltd. focuses on the supply of special alloys and precision materials for industrial applications.

For S4J38A projects, we can support customers with:

• Material specification review

• Customized dimensions

• Precision alloy sourcing

• Wire and strip supply

• Sheet and other product forms

• CTE requirements

• Chemical composition requirements

• Material certification

• Batch traceability

• Export packaging

• Technical communication

For new sealing projects, we recommend providing the glass or ceramic specification before material selection.

S4J38A Sealing Alloy FAQ

What is S4J38A sealing alloy?

S4J38A is a Fe-Ni-Co-Cu controlled expansion sealing alloy designation used for applications requiring controlled thermal expansion and metal-to-glass or metal-to-ceramic sealing.

What is S4J38A used for?

S4J38A can be evaluated for ceramic-to-metal sealing, glass-to-metal sealing, hermetic electronic packaging, semiconductor components, aerospace electronics and medical electronic applications.

Is S4J38A a controlled expansion alloy?

Yes. S4J38A is positioned as a controlled expansion sealing alloy, with material selection based on the required thermal expansion relationship between the metal and the sealing material.

Can S4J38A be used for ceramic-to-metal sealing?

Yes. S4J38A can be evaluated for ceramic-to-metal sealing when its thermal expansion characteristics are compatible with the selected ceramic and sealing process.

Can S4J38A be used for glass-to-metal sealing?

Yes. S4J38A can be considered for selected glass-to-metal sealing applications where the alloy and glass have suitable thermal expansion compatibility.

What is the CTE of S4J38A?

The required CTE should be specified according to the customer's temperature range and application. The certified CTE value should be confirmed using the applicable material specification and test report rather than relying on a single nominal value.

What is the chemical composition of S4J38A?

S4J38A is identified as an Fe-Ni-Co-Cu alloy on this product specification. Exact elemental ranges should be confirmed against the applicable S4J38A technical specification or material certificate.

Is S4J38A the same as 4J38?

Not necessarily. Standardized 4J38 is a different low-expansion Fe-Ni-Se alloy designation. S4J38A should only be treated as equivalent to another standard grade when chemical composition, CTE and applicable specifications have been formally verified.

Can S4J38A be supplied as strip?

S4J38A can be evaluated for strip supply according to the required thickness, width, tolerance and production requirements.

Can S4J38A be customized?

Yes. Product dimensions, material condition, surface requirements and inspection specifications can be discussed according to customer drawings and application requirements.

Can you provide a material certificate?

Material certificates and inspection documentation can be discussed according to the agreed specification and order requirements.

Request a Quote for S4J38A Sealing Alloy

Looking for a S4J38A sealing alloy manufacturer or supplier?

Please send us:

• Required alloy designation

• Glass or ceramic grade

• Glass / ceramic CTE

• Sealing temperature

• Operating temperature

• Product form

• Thickness / diameter

• Width / length

• Dimensional tolerance

• Quantity

• Required inspection

• Material certificate requirements

Our technical team can review your requirements and recommend the appropriate S4J38A Fe-Ni-Co-Cu controlled expansion sealing alloy specification.

Request a quotation for S4J38A sealing alloy today.