Rubber-to-Metal Bonding Failure: Analyzing Adhesive vs. Material Separation.

Rubber-to-Metal Bonding Failure: Analyzing Adhesive vs. Material Separation

Problem Statement

A rubber-to-metal bonded engine mount exhibited premature failure during thermal cycling at 150°C. Inspection revealed separation at the rubber-metal interface, raising questions about adhesive vs. material failure.

Material Science Analysis

The failure occurred due to insufficient thermal stability of the NBR compound. NBR lacks the fluorine content found in FKM, which provides superior heat resistance. The adhesive (Chemlok 205) remained intact, indicating material degradation rather than adhesive failure. Fluorine atoms in FKM form strong carbon-fluorine bonds, enhancing thermal and chemical resistance.

Technical Specs

• Material: FKM (Fluorocarbon Rubber)
• Shore A Hardness: 75 ± 5
• Tensile Strength: 15 MPa
• Elongation at Break: 200%
• Temperature Range: -20°C to 200°C
• Compression Set: 15% (22 hrs @ 200°C)

Material Comparison

Parameter	FKM	NBR	EPDM
Temperature Range (°C)	-20 to 200	-40 to 120	-50 to 150
Compression Set (%)	15	35	20
Chemical Resistance	Excellent	Good	Fair
Adhesion Strength (MPa)	8.5	7.0	6.5

Standard Compliance

RubberQ adheres to IATF 16949 standards, ensuring batch-to-batch consistency. Our process includes:

• Surface preparation per ASTM D429.
• Material callouts compliant with ASTM D2000.
• Cleanliness verification per ISO 16232.

For custom material compound development or IATF 16949 documentation, consult RubberQ’s engineering department.