Powder metallurgy has long since developed from a niche technology to an integral part of modern manufacturing processes whereby this fascinating and versatile manufacturing process has become indispensable in numerous industrial sectors. Whether in the automotive industry, medical technology or aerospace - the production of components from metallic powders offers unique advantages over conventional casting or machining techniques
In this blog article, we take a practical look at the strengths of boron nitride in powder metallurgy with a compact overview for anyone looking for high-performance solutions in practice.
Metal atomization is one of the key processes for the production of high-quality metal powders; especially when fine grain size, controlled properties and reproducible quality are required. The process is used whenever powdered metals are required, for example for sintering, additive manufacturing or for complex high-performance materials such as hard metals or magnetic alloys. Issues such as lightweight construction, individualized components and more efficient use of resources are also contributing to the fact that more and more companies are turning to atomized metal powder, not least due to the growing use of metallic 3D printing in industry.
A whole range of metals and alloys are used: Stainless steel, titanium, aluminum, nickel-based alloys, copper, cobalt-chromium or even refractory metals such as tungsten and molybdenum. Depending on the material and field of application, the choice is between gas atomization for particularly clean, spherical powder or water atomization, which is more cost-efficient but involves a coarser structure.
First and foremost, a uniform particle size of the metal powder, a shape that is as spherical as possible for good flow behavior and low oxidation - especially with reactive metals. The cooling rate also plays a role, as it influences the microstructure of the powder. For industrial applications, one thing counts above all: consistent quality with every batch.
Conventional steel or iron powders do not pose any major challenges for metal atomization and get by with standard nozzle materials such as zirconium dioxide. However, when it comes to specialties, the quality requirements increase rapidly. Certain particle size distributions of the metal powders are required or even the shape of the powder particles is a decisive factor. The quality of the powders is determined by the narrow and constant particle size distributions. These requirements must be guaranteed with process reliability and require maximum precision during the atomization process.
In powder metallurgy, quality cannot be achieved without quantity. In order to operate the metal atomization process economically, the powder yield must be as high as possible and the reject rate correspondingly low. Long downtimes or maintenance times must be avoided and the energy used must be utilized as efficiently as possible.
This is where our HeBoSint® SL-N 300 comes into play.
HeBoSint® SL-N 300 is a boron nitride-silicon aluminum oxynitride mixed ceramic that has been specially developed for contact with molten metal. It exhibits an optimized wear behaviour and an excellent non-wetting behavior that prevents clogging of the nozzle whilst ensuring not only a continuous process with uniform particle size of the metal powder but also a long service life and repeated use of the nozzle - batch after batch. The low thermal expansion of boron nitride in general ensures uniform powder particles.
Boron nitride is hot-pressed in the form of a sintered body and then manufactured into precise components using conventional machining methods. Conventional nozzles made of zirconium dioxide or aluminum dioxide are usually green-machined and the final step is sintering, which can lead to fluctuations in the component geometry. In particular, the tolerances of the nozzle bore, which is critical for atomization, can be kept significantly lower with the HeBoSint® SL-N 300. In the process itself, the precise nozzle and the low thermal expansion of the boron nitride can be used to specifically influence the particle shape and distribution.
An additional advantage is the excellent thermal shock behavior of boron nitride ceramic. There is no need for extensive preheating of the nozzle, which reduces preparation time and energy consumption. Using HeBoSint® SL-N 300 as a nozzle material can reduce process costs and increase quality at the same time.
With the growing use of additive manufacturing processes, the development of new alloys and the increasing demand for individualized, high-performance components, the importance of powder metallurgy will continue to grow. Materials such as HeBoSint® SL-N 300 will play a key role in making processes even more stable, economical and precise. Further developments in material design and production technology could even expand the range of applications for boron nitride - for example in the field of additive manufacturing or for particularly reactive melts.
