Silver Tin Oxide (AgSnO2) contact chips are engineered electrical switching interfaces designed for heavy-duty power switching devices handling high current surges. They provide a cadmium-free, RoHS-compliant solution offering arc welding resistance, thermal stability, and low material erosion under demanding AC and DC electrical loads.
Material Formulations & Microstructure
AgSnO2 88/12 Composition: 88% Silver, 12% Tin Oxide. Standard formulation balancing arc erosion resistance with low contact resistance.
AgSnO2 90/10 Composition: 90% Silver, 10% Tin Oxide. Formulated to lower contact resistance and millivolt drop in temperature-sensitive relays.
Doped Oxide Modifications: Controlled additions of Indium Oxide (In2O3, 0.5% - 2.0%) or Tungsten Oxide (WO3, 0.2% - 1.0%) refine grain boundaries and suppress oxide particle agglomeration during thermal cycling.
Technical Advantages
Anti-Welding Performance: Uniformly dispersed oxide particles help disrupt liquid metal bridging formed during high-current interruption.
Environmental Compliance: 100% Cadmium-free, compliant with EU RoHS Directive 2011/65/EU and REACH regulations.
Low Material Erosion: Uniform dispersion of SnO2 particles minimizes surface erosion pitting and contact degradation over extended switching operations.
Mechanical Forms & Geometries
Flat Square & Rectangular Chips: Length 2.0 - 25.0 mm, Width 2.0 - 20.0 mm, Thickness 0.5 - 4.0 mm.
Discs & Domed Profiles: Outer Diameter 3.0 - 20.0 mm, Spherical Crown Radius R10 - R50 mm.
Bimetal Strip Cutouts: AgSnO2 functional layer metallurgically bonded to a copper base layer with standardized layer thickness ratios (70/30 or 50/50).
Key Technical Specifications
|
Parameter |
Specification / Tolerance |
|
Silver Content (Ag) |
86.0% - 92.0% |
|
Material Density |
≥ 9.8 - 10.1 g/cm3 |
|
Microhardness |
80 - 120 HV0.5 |
|
Electrical Conductivity |
38 - 48 MS/m (65% - 82% IACS) |
|
Bimetal Shear Strength |
≥ 150 MPa |
|
Dimensional Tolerance |
Width/Length +/- 0.03 mm, Thickness +/- 0.02 mm |
|
Oxide Particle Size |
D50 ≤ 3.0 um (uniform dispersion) |
Electrical Performance Characteristics
Inrush Current Endurance: Designed to withstand peak inrush current transients up to 800 A (10 ms duration) under baseline testing without surface melting or contact welding.
Thermal Degradation Stability: Dispersed oxide phase maintains structural stability against grain coarsening at localized arc contact temperatures up to 900 deg C.
Low Millivolt Drop: Maintains low contact resistance (typically < 30 mV drop under rated operating current and contact force over baseline electrical life testing).
Primary Applications
Industrial AC Contactors: Switching contact tips rated from 9 A to 630 A for motor control centers and power distribution systems.
Molded Case Circuit Breakers (MCCB): Main arcing contacts for fault-current interruption equipment.
Automotive Relays: High-lamp load and inductive motor-start control units subject to severe inrush current transients.
Layer Construction & Backing Options
Layer Construction: Available in Solid Alloy, Bimetal (Copper backing), or Tri-metal configurations (featuring a pure silver intermediate layer 0.05 - 0.15 mm to facilitate thermal and electrical conduction).
Backing & Brazing Preforms: Fine silver backing layer, solderable flux plating, or pre-applied silver brazing alloy layer (Ag-Cu-Zn solder 0.05 - 0.10 mm) for automated joining.
Custom Geometries: Stamped profiles produced to customer CAD specifications, including chamfered edges, positioning locator dimples, and custom radius crowns.
Quality Assurance & Verification
Ultrasonic Bond Inspection: 100% C-scan acoustic testing to detect interface micro-voids, unbonded areas, or delamination between silver alloy and copper backing layers.
Elemental Composition Analysis: X-Ray Fluorescence (XRF) and Inductively Coupled Plasma (ICP) testing to verify chemical composition and trace impurity limits.
Metallographic Examination: Microstructural analysis verifying fine SnO2 particle dispersion with agglomerate sizes strictly controlled below 3 um.
Packaging & Automated Assembly Support
Vacuum Anti-Oxidation Packaging: Sealed in heavy-duty moisture-barrier bags with desiccant packaging (1,000 to 5,000 units per bag).
Automated Line Packaging: Available in precision thermoformed Tape & Reel or Matrix Trays optimized for automatic pick-and-place systems and high-speed brazing machinery.
Export Packaging: Packed in reinforced double-wall corrugated cartons with outer poly-banding for international sea and air freight protection.
Technical Inquiries & Selection RFQ Requirements
To help our engineering team provide an accurate quotation and technical recommendation, please provide the following parameters when submitting an inquiry:
Target Application & Device Type ( AC Contactor, Automotive Relay, MCCB).
Operating Conditions: Rated current (A), voltage (V), load type (inductive, resistive, lamp load), and peak inrush current.
Dimensions & Profile: Length, width, thickness, radius crown, or step geometry (CAD drawing preferred in .STEP or .DWG format).
Structure & Layer Ratio: Solid, Bimetal (AgSnO2/Cu), or Tri-metal, including required backing layer thickness.
Backing Requirement: Plain backing, silver-plated, or pre-brazed solder coating.
Frequently Asked Questions
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