Furnaces for High Temperature Sintering of Technical Oxide Ceramics
Debinding and sintering of technical oxide ceramics usually takes place in air atmosphere. For the debinding processes (debinding of green parts) most manufacturers use accordingly modified chamber furnaces with an efficient air circulation system for high temperature uniformity and a catalytic or thermal converter for waste gas cleaning. Subsequently the parts (brown parts) are sintered at up to 1800°C in a separate high temperature furnace.
Examples of sintered ceramics
A debinding/sintering line can, for instance, be composed of a furnace combination, which consists of a debinding furnace and a high temperature sintering furnace
Debinding Furnace
- Hot zone made of heat resistant stainless steel
- Special sealing of furnace door
- Fresh air inlet by means of ball cock valve
- Exhaust with automatically controlled vapor vent flaps
- Inert-gas inlet and outlet for furnace operation
- Catalytic converter or thermal post combustion for waste gas treatment
Options:
- Air preheating system
- Protective gas purging
- Gas-tight retort
- Loading aids like forklift stacker, etc.
High Temperature Sintering Furnace
- Delivery of custom-made furnaces precisely tailored to the desired process
- Different maximum temperatures available either 1600°C or 1750°C or 1800°C
- Either SiC or MoSi2 heating elements, depending on maximum operating temperature
- Double-walled housing with air cooling to maintain low level outside temperature
- Insulation made of high-grade Al2O3-fibre with low thermal mass for fast heating and cooling. Exhaust with manual flap in the roof
- State-of-the-art switchgear and control technology. Heating elements controlled by thyristors for very precise temperature control, wear-free and noiseless
Many of our customers decide for a combo-furnace meaning debinding and sintering in one process cycle. Such a furnace avoids an additional unloading/loading procedure between debinding and sintering furnace and will thus reduce damages on very sensitive brown parts.
Example: Debinding/Sintering Furnace Type IHO
- Gas-tight, double-walled housing in stainless steel
- Integrated design for debinding and sintering in one cycle
- Multilayer quality fiber insulation for different application temperatures
- Various heating systems possible
- Up-scaling of processes to larger production volumes are easy and without risk
- Furnace sizes from laboratory applications to production scale
- Safe elevator drive (lift bottom)
- Several system solutions for product charging and handing
- Robust design for production and industrial application
- Safe conversion of waste gases by either catayltic or thermal post combustion
- Short cycle times by means of a rapid cooling device (optional)
- Siemens S7 PLC with Siemens operator panel
Advantages:
- Debinding and sintering without interruption
- Residue-free driving off binders
- Ability to use inert-gas for debinding
- Sintering under high purity atmosphere (low residual oxygen)
- Furnace structure in double-wall design to maintain safe outer housing temperatures
- Multilayer fiber insulation with low thermal mass allowing for fast temperature changes
- Energy savings through reduced specific energy consumption
- Inert gas backflushing of the fibrous insulation extends the lifetime of the insulation
- Guided gas routing to avoid binder residues and other contaminants
- Fast gas exchange rates or rapid cooling device for shortening cycle times
Separate furnaces and combi-furnaces for debinding and sintering each have their pros and cons. Which system suits best to your process, your material, your workpiece geometry and your work-flow, we would be pleased to work out in a close cooperation with you.