GE Aviation plans to build two adjacent factories in Huntsville, Alabama, to mass-produce silicon carbide (SiC) materials used to manufacture ceramic matrix composite components (CMCs) for jet engines and land-based gas turbines, the company announced Tuesday. The company said construction will cost it more than $200 million. Expected to enter operation in mid-2018, the factories will employ as many as 300 people, according to GE.
Alabama Governor Robert Bentley and members of the Alabama delegation at the state capital in Montgomery joined GE Aviation’s CMC program vice president Sanjay Correa in Huntsville to announce the plans. “Establishing the new GE factories in Alabama is a very significant step in developing the supply chain we need in order to produce CMC components in large volume,” said Correa.
Plans call for one plant to produce silicon carbide ceramic fiber. Today, NGS Advanced Fibers in Japan—a joint company of Nippon Carbon, GE and Safran of France—operates the only large-scale SiC ceramic fiber factory in the world. The adjacent GE factory in Alabama will use the SiC ceramic fiber to produce the unidirectional CMC tape necessary to fabricate CMC components.
GE expects to start building the two plants in mid-2016 and complete construction by the first half of 2018. GE has already begun hiring the technical team that will transfer to the Huntsville operation and it expects to begin hiring the hourly workforce in late 2016.
GE considers the use of CMCs in the hot section of GE jet engines a “breakthrough” for the jet propulsion industry. CMCs comprise SiC ceramic fibers in a SiC matrix, enhanced by proprietary coatings.
Carrying one-third the density of metal alloys, CMCs reduce engine weight and their high-temperature properties enhance engine performance, durability and fuel economy. Far more heat resistant than metal alloys, CMCs require less cooling air in the engine’s hot section.
Scientists at GE’s Global Research Centers and GE’s industrial businesses have worked to develop CMCs for commercial applications for more than 20 years. The new Leap turbofan, developed by the GE-Snecma joint venture CFM International, is the first commercial jet engine to use CMCs in the high-pressure turbine. Schedules call for it to enter airline service next year on the Airbus A320neo, and in 2017 on the Boeing 737 Max.
Supported by $21.9 million in funding from the U.S. Air Force Research Lab Title III Office, the ceramic fiber plant will license fiber-producing technology from Japan’s NGS Advanced Fibers, in which GE holds a 25 percent stake. NGS, which already produces SiC fibers for GE’s CMC components, plans to open a second factory in Japan to increase production capacity. The GE fiber plant in Huntsville will complement the growing capacity at NGS.
Once the Huntsville plant enters operation, it will sell fiber to the Department of Defense, GE businesses, fellow NGS stakeholder Herakles Safran of France and other outside customers subject to U.S. regulations. The two other NGS partners—50-percent owner Nippon Carbon of Japan and Herakles Safran—will ultimately get a chance to become equity partners in the Huntsville plant, said GE.
The adjacent plant, financed solely by GE, will apply proprietary coatings to the ceramic fiber and form them into a matrix to produce CMC tape. GE Aviation plans to use the ceramic tape at its new CMC manufacturing site in Asheville, N.C., which opened last year. The Asheville facility fabricates CMC shrouds for the Leap engine’s high-pressure turbine section.
Meanwhile, GE continues its testing of CMCs for the GE9X, a new 100,000-pound-thrust-class turbofan chosen to power both variants of the Boeing 777X. Using a GEnx test engine at its Peebles, Ohio testing facility, GE in January began ground testing of CMC components in the high-pressure turbine (HPT) and combustor.
Part of the advertised fuel-burn improvement in the GE9X will come from what GE advertises as the highest pressure ratios among any commercial engine in production; the 9X design calls for a 60:1 overall pressure ratio and a 27:1 pressure ratio in the high-pressure compressor. Of course, higher pressure ratio means a higher operating temperature in the back of the compressor and high-pressure turbine, necessitating the development of new nickel-based disc alloys and CMCs for the inner and outer combustion liner, the Stage 1 high-pressure turbine shroud and the Stage 1 and 2 high-pressure turbine nozzles. The design of the 9X calls for the most extensive use of CMCs ever by GE Aviation.