Aluminum Nitride Ceramic Heaters


Rapid Fire™ Aluminum Nitride (AlN) Heaters

Durex Industries’ Rapid Fire aluminum nitride (AlN) ceramic heater solutions combine the thermal conductivity of aluminum and dielectric strength of specialty ceramics with physical properties similar to stainless steel. Additionally, a tungsten (W) RTD Sensor is integrated into the multi-layer heater construction to provide maximum control of this high watt density heater. New levels of machine design and thermal performance can be achieved through the excellent thermal, dielectric and physical properties of AlN heaters.

Ceramic heater technologies offer significant advantages over metal based sheath heaters that have limitations in thermal performance or material compatibility. Durex’ ceramic heaters can operate in atmospheric and vacuum environments up to 1000°C (1832°F). With its excellent thermal conductivity, AlN heaters can be designed with a multilayer construction that can deliver up to 2000 W/in2 (310 W/cm2 ). With chemical resistance to most acidic and alkaline solutions, these compact robust heaters are an ideal solution for demanding thermal applications. Ceramic heaters can be custom designed to optimize thermal performance for instrumentation and equipment applications.

Rapid Fire AIN Advantages

  • Thermal conductivity equivalent to aluminum for fast and uniform thermal response
  • Watt density higher than any metal or ceramic heater technology for concentrated heat in a small area
  • Integrated RTD sensor for optimum heater temperature control
  • Dielectric strength eliminates need for magnesium oxide insulation (MgO) layer used in metal heaters
  • Heater temperature up to 1000°C (1832°F) for high-temperature applications
  • Low porosity non-stick surface reduces potential for process contamination
  • Chemically inert to most acid and alkaline environments
  • High mechanical strength, hardness and wear resistance for industrial applications

AlN Heater Capabilities

  • Thermal conductivity equivalent to aluminum for fast and uniform thermal response
  • Watt density: up to 2000 W/in2 (310 W/cm2)
  • AlN thermal conductivity: 180 W/mK
  • Rapid ramp rate: 0-400°C (32 to 752°F) in less than 2 seconds
  • Atmospheric and inert gas environments applications
  • Complex and 3-dimensional geometries
  • Thickness: 0.05 in. to 0.200 in (1.27 mm to 5.08 mm)
  • Size: Up to 10.25 in2 (66.13 cm2 )
  • Encapsulated tungsten (W) RTD sensor
  • Surface tungsten (W) or nickel (Ni) metallization

Multi-Layer Ceramic Heater Design and Manufacturing

Multi-Layer Ceramic Heaters
Multi-layer AlN heater design and manufacturing processes extend the capability and functionality of AlN thermal solutions. Starting with green state (power) ceramic materials, each layer is formed and pressed to the required dimensions. Metallic heater and sensor layers are sandwiched and pressed between the ceramic layers. The entire assembly is then sintered in a high-temperature furnace to create a monolithic assembly. Layers may include a combination of heater circuits, RTD sensor elements, ground planes, radio frequency (RF) grids, metallic and ceramic flow channels.

AlN heaters are used in applications where low thermal expansion and/ or high thermal conductivity are required. When combined with internal chemically-bonded metallic conductors, these components may be used in high power electronic devices and rapid thermal cycling processes. Very high power densities can be realized by designing a solution with metallic structures for mounting and heat removal.

Cylindrical 3D AlN Heaters

Precision manufacturing processes and machining capabilities allow for unique 3D designs such as a cylindrical (tube) heater. Cylindrical heater applications include gas and liquid heating in instrumentation such as gas chromatographs, mass spectrometers, and medical devices. Cylindrical heaters can be designed for process temperatures in excess of 600°C (1112°F) with watt densities up to 1000 W/in2 (155 W/cm2). With design flexibility to distribute wattage and vary the length as well as inside and outside diameter, this heater can be customized to optimize performance in the application.

Z-AXIS Thermal Solution™

Traditional industrial heater designs are usually 2-dimensional and have inherent heat transfer and thermal solution limitations. Durex’ aluminum nitride (AlN) ceramic heater technology gives engineers the ability to actualize a Z-axis thermal solution. The AlN material layers and circuits are sintered at high temperature to form a monolithic 3-dimensional solution. This integrated thermal solution may include multi-layers of heater circuits, RTD sensor elements, RF grids, ground plains, cooling, gas and vacuum channels.

Sheath Material Thermal and Physical Properties