Vacuum Bonding & Other Methods of Attachment

The following installation methods are used for the application of ceramic tiles:

ADHESIVE BONDING

• Two-part epoxy or Silicone Adhesives
• Vacuum Bonding

MECHANICAL ATTACHMENT

• Weldable tiles
• Interlocking

VACUUM BONDING TECHNOLOGY

Vacuum bonding is an advanced bonding technology that combines specialty structural adhesives, wear resistant materials and controlled processing. Applications which require high reliability, high impact resistance and wear protection are ideal candidates for vacuum bonding solutions. Vacuum bonding has been refined by Thermo Vac into a state of the art technology that gives bonding strengths which can never be achieved with standard adhesives.

Valuable features of vacuum bonded materials are:

• Increased impact resistance of hard wear resistant ceramics.
• Unparalleled performance in dynamic applications
• Extremely high sheer strengths
• Proven performance in light weight designs with ceramic linings as thin as 3 mm thick.
• Existing equipment and complex shapes are lined without redesign.
• Bonded linings can be machined to fit tolerances.
• Extremely high reliability in critical moving applications.

Vacuum bonding is an ideal solution in many tough applications like:

• Fan blades
• Mixer housings and blades
• Valve gates
• Screw conveyors
• Pump volutes

A summary of the Thermo Vac´s vacuum bonding technology gives the following qualities:

• The only bond for dynamic applications
• Used in most power plant applications
• Excellent for dynamic applications with high stress
• Increased resistance to impact and vibration
• Maximum temperature for dynamic applications 135 °C
• Maximum temperature for static applications 325 °C
• High shear and tensile strengths; 31 MPa shear and 41.5 MPa tensile
• Highest installed cost for ceramics

BRAZING

Brazing is used to attach tungsten carbide to steel substrates. Very high bond strengths are achieved; 280 - 500 MPa tensile and 175 MPa shear. It has full bond strength at 1000 °C, and excellent impact resistance.

MECHANICAL ATTACHMENT

Weldable clips or interlocking shapes can be used with most wear materials. The combination of standard adhesives and mechanical attachment provides a cost effective system for medium or low impact applications.

 Summary of qualities:

• Mid-range installed cost for ceramics
• To be best used for static applications with medium impact.
• Secure attachment in higher temperatures.
• To be used for applications with maximum temperatures of 400 °C.

STANDARD ADHESIVES

RTV Silicone and Two Part Epoxies are used in low stress applications, usually together with mechanically attached materials. Normal maximum strengths are 7 MPa tensile and 5.5 MPa shear. RTV silicone is used in temperatures up to 260 °C and epoxy is used in temperatures up to 65 °C. Special adhesives can resist considerable higher temperatures.

Summary of qualities:

• Lowest installed cost for ceramics
• To be used for static applications with low stress
• To be used for applications with minimal vibration or impact
• To be used for applications with maximum temperatures of 260 °C
• Low shear and tensile strengths; 5.5 MPa shear, 10 MPa tensile

COMPOSITE TECHNOLOGY

Thermo Vac´s composite technology uses a variety of dissimilar materials that when bonded together form a system which is superior to the individual components. This system puts the strongest wear materials in the highest wear area and the more cost effective materials in the less intensive areas, all on the same wear surface. The technology may seem simple, but is based on research and development during a long time and puts demands on experience and equipment.

Conclusion:
Vacuum bonded ceramics combined in a system with other wear protective materials like carbides, gives the best and in the long term most cost effective wear protection for severe applications!