Even at the highest temperatures, our hot zones don't feel the heat. They are designed for temperatures between 1 000°C (1 832°F) and 2800°C (5072°F).
We are experts in the field of thermal processes: whether in high vacuum, protective gas atmospheres or during hot isostatic pressing (HIP). And for any questions you have about sintering, brazing, annealing and heating systems, we are the right people to ask.
Is your process not yet on the list? That makes it all the more exciting. Because we regularly develop hot zones for new thermal processes in collaboration with system engineers and users. And precisely in growth sectors such as sapphire or silicon crystal growing, it is important for us to work with you right from the development phase in order to come to the optimum solution.
Our range at a glance.
Hot zones consist of countless individual parts such as heating elements, shield packs and hearth assemblies and charge carriers. You can find all of these components at Plansee.
- Hot zones made from molybdenum, tungsten, tantalum, niobium and their alloys
- Full metal or hybrid hot zones with graphite or ceramic fiber insulation
- From very small (a few cm³) through to very large (several m³) hot zones
- For temperatures of between 1000°C (1832°F) and 2800°C (5072°F)
- Tailor-made design: round, rectangular, vertical, horizontal or special geometries
By ensuring the correct configuration of the heat shielding and heating capacity, our team makes certain that there is a uniform temperature throughout the furnace and simultaneously reduces heat losses. We will choose the materials for your hot zone individually to meet your specific needs. For temperatures of around 1300 °C (2372°F), we supply molybdenum hot zones with steel supporting frames. At temperatures of 1700 °C (3092°F) or above, we mostly choose tungsten for the components exposed to the greatest thermal stress. Our hybrid hot zones have graphite felt or ceramic fiber insulation.
Why use metallic hot zones?
Fully metallic furnaces are the clean solution for particularly demanding applications. Graphite furnaces frequently cause impurities due to the presence of carbon – a highly reactive material that can damage your products. In contrast, metallic furnaces with hot zones from Plansee do not suffer from this problem. They are exceptionally clean and guaranteed carbon-free.
Below is a summary of the advantages you benefit from:
- higher ultimate vacuums
- No contamination due to oxygen, humidity or carbon
- Short cycle times
- Extremely fast quenching with high gas pressures
- Special metal alloys for outstanding dimensional stability
When other materials give up, it's time for molybdenum and tungsten to take over. These two materials are both refractory metals and are ideally suited for use at high temperatures. With their special properties, molybdenum and tungsten are the perfect choice for components in the furnace construction industry.
- High melting points permitting operating temperatures of up to 2800°C (5072°F)
- Outstanding creep resistance
- High level of dimensional stability
- Extremely pure
- Excellent corrosion resistance
- Low coefficient of expansion
Whenever materials have to meet special challenges, we add titanium and zirconium to strengthen the microstructure of pure molybdenum. Mo-Ti solid solution and Ti-Zr carbides ensure that optimum strengths are achieved at temperatures up to 1400°C (2552°F).
What can TZM do better than pure molybdenum?
- Better creep resistance
- Higher recrystallization temperature
- Greater thermal stability
By using suitable alloys and optimized production processes, we are able to improve the properties of molybdenum. To achieve a particularly high level of ductility and creep resistance, we dope pure molybdenum with small quantities of La2O3. The stabilized microstructure and modified recrystallization behavior prevent the premature embrittlement and fracture of our furnace components.
What makes ML better than pure molybdenum?
Enerzone®. Unbeatable efficiency.
- Higher recrystallization temperature
- Elongated grain structure for higher ductility
- Greater creep resistance
Less mass, better shielding and ceramic fiber insulation. That is the secret of our new low energy hot zones. Although they consume 20 - 25 % less energy, they still outperform conventional metal hot zones.
One example: In a furnace, less weight means faster heating, a shorter heating cycle and reduced energy consumption. In order to reduce energy consumption in the furnace through the use of a special lightweight construction, we have replaced pure molybdenum with the molybdenum alloys ML and TZM. Thanks to the exceptional strength of the material, we can use significantly thinner shieldpacks and charge carrier components. In addition, we have replaced a number of stainless steel components with molybdenum. This is because a single layer of molybdenum has the same shielding effect as five layers of steel.
Planned to the last detail.
We have a team of ten engineers specializing entirely in furnace construction. Whether in the field of coating systems, annealing furnaces or sintering furnaces: We are experts in all high-temperature processes. Taking account of the atmosphere, cycle times and temperatures, we will work together with you to fine-tune the very best solution for your furnace. Every detail must be right. FEM analyses help make sure there are no mistakes. For example, we can simulate how your hot zone will function in live operation.
In complex projects, our team of engineers constructs models using 3D computer drawings. And before production starts, everything is checked right down to the last detail. For our engineers, good isn't good enough. As a result, our team often comes up with some very special solutions. One example: In the past, hot zones have always been designed to lie in the same plane. This has a disadvantage: In very large furnace installations, these hot zones soon start to sag at high temperatures. This leads to short-circuits, fractures and downtimes. The new Plansee-patented design is curved. Sagging? No thank you!
A giant? Of course, it's one of ours.
50000 individual parts and eight meters long. Clearly a case for Plansee - and a very big one, too. The largest hot zone that we have ever manufactured is a construction weighing more than six tonnes. Our team had to work hard to achieve this feat: from design right through to installation in the boiler at the customer's premises. It was even necessary to develop new tools for the demanding heating components.
However, the effort was worthwhile: The result is an innovative heating insert in proven Plansee quality. Are you planning something big? Tell us about it.
It makes no difference whether you need an entire hot zone or simply a spare part for your existing furnace. With Plansee, you are in good hands. We are happy to install your products for you at your premises. And, of course, we are there to lend a hand when it comes to inspecting, maintaining and optimizing existing furnaces.