INDUSTRY COMPONENT

Bonding Layer

Bonding layer for tungsten-rhenium target disks in X-ray tubes and medical imaging equipment.

Component Specifications

Definition
A specialized adhesive interface layer that permanently bonds tungsten-rhenium alloy target disks to their copper heat sinks in rotating anode X-ray tubes. This component ensures optimal thermal conductivity while maintaining structural integrity under extreme thermal cycling (up to 2500°C surface temperatures) and centrifugal forces (up to 10,000 RPM).
Working Principle
The bonding layer functions as a thermal and mechanical interface that transfers heat from the tungsten-rhenium target disk to the copper heat sink through conductive heat transfer. It maintains adhesion through differential thermal expansion management, using compliant materials that accommodate the mismatch between tungsten-rhenium (CTE: 4.5×10⁻⁶/K) and copper (CTE: 17×10⁻⁶/K) while preventing delamination under operational stresses.
Materials
High-temperature brazing alloys: Silver-copper eutectic (Ag72Cu28), Gold-copper (Au80Cu20), or specialized nickel-based alloys with titanium/vanadium additives for enhanced wetting and bonding strength. Thickness typically 50-150 μm.
Technical Parameters
ParameterTypical rangeNotes & selection driver
Void Content<2%
Bond Strength≥80 MPa at 400°C
Thickness Tolerance±10 μm
Thermal Conductivity≥200 W/m·K
Thermal Cycling Endurance>50,000 cycles (20°C to 400°C)
Operating Temperature Range-50°C to 600°C

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards
ISO 9712, ASTM E8, DIN 50125, ISO 17672

Parent Products

This component is used in the following industrial products

Engineering Analysis

Risks & Mitigation
  • Delamination under thermal stress
  • Void formation during brazing
  • Intermetallic compound formation reducing ductility
  • Thermal fatigue cracking
  • Inadequate wetting leading to poor adhesion
FMEA Triads
Trigger: Insufficient surface preparation or contamination
Failure: Poor adhesion leading to delamination
Mitigation: Implement strict cleaning protocols (ultrasonic cleaning in acetone/isopropanol), plasma surface activation, and controlled atmosphere brazing (vacuum or inert gas)
Trigger: Thermal expansion mismatch stress
Failure: Cracking or debonding during thermal cycling
Mitigation: Use compliant interlayer materials, graded bonding approaches, and finite element analysis to optimize thickness and material selection for stress distribution
Trigger: Excessive intermetallic formation
Failure: Brittle interface reducing mechanical strength
Mitigation: Control brazing temperature/time profiles, use barrier layers (nickel, titanium), and select alloys with slower diffusion rates

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance
Thickness: ±10 μm, Flatness: <5 μm over 100 mm diameter, Void area: <2% of bond area
Test Method
Ultrasonic testing per ASTM E317, Shear strength testing per ISO 4587 at elevated temperatures, Thermal cycling per IEC 60601-2-54, Microstructural analysis per ASTM E3

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation
Request current drawings, revision history, and a signed specification sheet.
Manufacturing capability
Verify equipment lists, process limits, capacity, and representative production evidence.
Inspection readiness
Confirm test methods, calibrated equipment, sampling plans, and traceable reports.
Supplier transparency
Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Bonding Layer

Manufacturer profiles associated with Bonding Layer.

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Frequently Asked Questions

Why is the bonding layer critical in tungsten-rhenium target disks?

The bonding layer prevents target disk delamination under extreme thermal cycling (up to 2500°C surface temperatures) and centrifugal forces (up to 10,000 RPM), ensuring continuous heat transfer to the copper heat sink and preventing catastrophic failure in medical X-ray equipment.

What materials are used for high-performance bonding layers?

High-temperature brazing alloys like silver-copper eutectic (Ag72Cu28) or gold-copper (Au80Cu20) are standard, with nickel-based alloys containing titanium/vanadium additives for enhanced wetting properties and oxidation resistance at elevated temperatures.

How is bonding layer quality verified?

Quality is verified through ultrasonic testing (void detection), shear strength testing at elevated temperatures, thermal cycling endurance tests, and microstructural analysis using scanning electron microscopy to ensure proper alloy diffusion and interface integrity.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification
This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

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