SiC Coating by Thermal Spray made possible (SiCoat)

De mekaniske, termiske, kjemiske og tribologiske egenskapene av til silisiumkarbid (SiC) er av stor interesse. Disse egenskapene gjør SiC et ideelt materiale for bruk i meget krevende anvendelser. På grunn av mangelen på smeltepunkt er SiC per i dag mest brukt som bulk materiale eller som sintrert. Dette betyr at silisiumkarbid går direkte fra fast stoff til gass ved sublimering). Derfor kan ikke termisk sprøyting brukes til å produsere SiC belegg. Derfor ble dette prosjektet etablert med det formål å bringe til markedet et så krevende termisk spraybelegg. Siden starten av dette prosjektet har Seram Coatings vært i stand til å flytte produksjonen av et laboratorieskala produkt til pilotskala. Gjennom hele prosjektets varighet har det foregått diskusjoner med mulige kunder. Prosjektet har vært sentralt for å forberede ThermaSiC pilot produksjonslinje for testing av produktakvslifisering. Det er produsert flere kilo kvalifiseringsmateriale med den nåværende pilotlinjen. Pilotproduktet er sendt til forskjellige potensielle klienter for testing. Dette har ført til å definere noen viktige applikasjoner for å forberede pilotlinjen for industrialisering. Blant disse viktige applikasjonene kan vi finne bremseskiver for både biler og sykler, stempler for glassindustrien og romapplikasjoner blant mange andre. Pilotmaterialet kvalifiseres for flytende drivstoff med høy hastighet oksygenbrensel (HVOF) og atmosfæriske plasmaspraymetoder (APS). En ny behandlingsrute utvikles ved FoU -anleggene for å fortette det nåværende pilotproduktet for å gjøre det mer egnet for plasma.

Despite many global efforts, no one has been able to produce SiC thermal spray coatings. SiCoat has made it possible for Seram Coatings to enable the lab production of SiC coatings to pilot level, making it ready for the market. At the project start, Seram Coatings' production was limited to few kilograms per day. Within this project, the production has been upscaled to several hundred kilos per month. A new production site has been established with a potential capacity of several tonnes per day. The production of SiC feedstock materials for thermal spray has now been patented in several countries by Seram Coatings. And a new product using a metal matrix is patent pending. Seram Coating´s business model has changed from R&D-based to market-driven business model. Seram Coatings has established its core business in Norway (split between R&D in Trøndelag and production in Porsgrunn), extending the Norwegian process industry offerm, improving the Norwegian value chain for coating services.

SiC (Silicon Carbide) is one of the most attractive ceramic coating material for wear and corrosion protection due to its excellent mechanical, chemical and thermal properties. Therefore, SiC has attracted considerable interest for aerospace components (turbine blades, moving components, thermal barrier coatings for rocket nozzles), automotive parts (turbochargers, valve train, fuel injectors etc.), metal working tools (cutting tools, drill bits), etc. However, despite the attractive properties of SiC, the lack of melting point at atmospheric pressure (SiC tends to decompose or sublimate at 2500-2600 °C) makes it an impossible material to be thermally sprayed, thus limiting the number of processes that can be used for producing SiC coatings to Physical Vapour Deposition (PVD) and Chemical Vapour Deposition (CVD). The main drawback of these technologies is that CVD and PVD are costly and slow processes that are considered unsuitable for producing SiC coatings on large-scale machine components as items to be coated must fit into a low pressure/vacuum chamber, while thermal spray is more versatile and large samples can be coated in a very simple and effective procedure. In 2014 Seram Coatings succeeded for the first time in producing SiC coatings using thermal spray technologies enabling their use on large machine parts, hence opening a vast industrial market for such coatings. The technology was protected and patented and it needs now to be further developed according to specific working conditions. Experience over the last years showed that thermal spraying is a complex technology with many parameters having strong influence on the final properties of the coating. Therefore this projects aims at demonstrating the viability of applying SiC coatings on two different market applications (demonstrators), verify the feasibility of expanding the use of these coatings from an industrial perspective and upscaling the powder production for covering the market demands.