PSI has been awarded a £1 million grant from the U.K's Technology Strategy Board (TSB) to develop ground breaking technology for the mass production of spherical, low oxygen, ceramic-free titanium powder at a fraction of current costs..
The grant provides match funding for a 3 year, £2 million programme undertaken in partnership with the University of Greenwich and Cambridge Quality Technology Ltd. As part of the UK Government's drive to lower weight in transportation applications and cut exhaust emissions (see www.technologyprogramme.org.uk) the Lightweight Materials and Structures Competition encouraged applicants who could demonstrate a significant advance in the relevant technology.
In this case, the ultimate objective is to remove cost and quality barriers, promoting the wider use of titanium in powder metallurgy (PM) components and extend its use, not just in the traditional aerospace and medical sectors, but to mass production applications in automotive and general engineering. Driven by the contrasting demands of a rapid expansion in aircraft construction and the parallel need to reduce global emissions, the demand for lightweight and strong structures, such as are provided by titanium, has never been higher.
The global market is responding by significantly increasing capacity in primary titanium extraction and simultaneously developing new methods to replace the outdated, expensive Kroll method with lower cost processes e.g. MER-Dupont, Armstrong and Fray. This, coupled with the further lowering of cost to convert primary titanium to spherical powder by the new PSI process, will enable the titanium PM sector to rapidly expand.
The potential for this sector has been identified for many years, research is complete, and prototypes have been successfully tested (photograph available) e.g. the engine thrust link for the new Boeing 787 'Dreamliner' supplied by GKN Aerospace. All that is required to release many new engineering applications is for titanium powder costs to fall. Powder Metallurgy, as the most rapidly growing metal forming technology, is expected to feature heavily in the expanded usage.
Over twenty years, PSI has progressively developed gas atomisation as a means of producing fine, pure and spherical, metal powders. More recently is has concentrated on improving yields and lowering costs of the valuable and fine fractions of atomised powders. To this end it has introduced "hot gas" atomistion to the market, constructed atomisers for continuous rather than batch production and fitted gas recycling, all with the objective of lower unit production cost.
Titanium poses a special challenge in that during the melting and feeding stage, as part of the atomising process, the liquid metal must not contact ceramic refractory at any stage; otherwise it will be contaminated by oxygen and ceramic inclusions rendering it unusable for many advanced aerospace applications.
"Cold Wall" melting and feeding techniques must be used throughout and this approach will be adopted in the programme enabling high quality, low cost aerospace grade powders to be made. To achieve low cost, production will be continuous and at a high throughput rate for similar reasons to those which led continuous casting to replace ingot casting in steel production. PSI's development in cold wall melting techniques now make this possible for titanium.
Although the inspiration for the programme was low-cost CP and Ti 6/4 grades, the technology will apply equally to more complex titanium allows and the clean melting techniques will be of interest to users of superalloy powders, nickel-titanium shape memory alloys and indeed any metal powders that are required to be ceramic inclusion-free.
To ensure rapid integration of the new technology into industrial production, the TSB require competition winners to identify exploitation routes at the outset. PSI therefore welcomes approaches by parties looking to acquire an early interest in the new technology.