Developing special, tailor-made silicon carbide powders together with our customers makes up a significant portion of the ongoing effort in the global silicon carbide innovation teams. At the end of such development process we end up with a silicon carbide powder having unique properties that will improve the customer’s manufacturing process or their end products. Some examples of silicon carbide properties that we can customize during the development process are:
Having the optimal PSD for the application is of key importance in most applications, whether sub-micrometer sized particles or large, millimeter-sized crystals are used. By carefully selecting the optimal crushing or milling technology together with the appropriate dry or wet classification techniques, the PSD can be optimized for the customer’s specific application.
By applying various chemical treatment procedures Saint-Gobain can purify the powder and remove certain elements, like silicon, carbon, iron and oxygen.
For certain high-tech applications very low content of specific elements (including trace elements) are required, something which can be addressed on a case-to-case basis. For other applications there might a need to dope certain elements into the silicon carbide in order to get the optimal chemistry.
The shape of the grains (from very sharp to round) can be addressed using various crushing and milling technologies. For some end applications, the correct grain shape can be crucial to achieving optimal performance.
Thickness and composition of the silica-layer present on the surface of the SiC-crystals will influence the reactivity of the powder, and can be carefully controlled by our manufacturing processes. The surface properties will also influence the pH of SiC-based slurries that customers produce for their casting processes. Being able to adjust the surface properties is therefore of great importance.
Having a certain electrical and/or thermal conductivity can be critical for some specific applications and having necessary knowhow to adjust such parameters is crucial.
The PSD and the particle shape will together highly influence the bulk density and the flow of most powders. In some cases there is still room to optimize the flow or the density of the powders.
The combination of these properties and the customers own processes determine the quality of the end product.By working closely together, within the framework of confidential agreements, we are able to achieve the best end results, like:
Sintered density very close to theoretical value, combined with extreme strength and excellent wear resistance. Typical applications are seal rings and hot-pressed armor protection.
Controlled porosity while maintaining high strength and excellent resistance to thermal shock. This is for example important when used in high temperature filtration applications.
Superb high temperature oxidation resistance, for instance in kiln furniture applications.