SBIR-STTR Award

MRi is proposing to investigate exothermic braze technology that will provide cost effectivemethods to join and attach ceramic composites to nickel base alloys and to themselves forfabricating CMC aircraft engine components. The initial application of this technology will beaimed at jet engine components for reliable, affordable high thrust to weight ratio jet enginesthat have been investigated under the VAATE programs. The engines developed under thisprogram have been targeted to power the US Army’s Joint Heavy Lift Transport. Theproposed program is a technology demonstration effort aimed at developing joiningtechnologies that utilize exothermic materials that upon ignition, react and generate over3,000ºC locally, enough to fuse and react adjoining CMC or CMC:metal surfaces. MRi hasteamed with Ohio Aerospace Institute (OAI) for their connection to the CMC joining work atNASA-Glenn Research Center and their capability to contribute to the proposed exothermicbrazing technology. MRi is also teaming with Exotherm Corporation for their expertise indesigning and manufacturing exothermic Phase I investigations would focus on design,analyzing and developing high energy density, refractory nano-phase braze mixtures andbraze processes for joining melt infiltrated SiC:SiC to superalloys and also to SiC:SiC.Various exothermic material systems will be investigated and demonstrated on small scaleflat SiC:SiC and superalloy coupons followed by metallographic evaluations and mechanicaltests.

Benefits:
The proposed nano-phase technology has applications for joining CMC materials for use inwide range of aircraft applications such as combustor liners, ducts, deflectors and enginenozzles. The technology also has application in joining CMC rocket engine nozzles andducts, thermal protection (TPS) systems for aero or space structure would be more easilyand cost effectively produced if such a cost effective joining technology were developed.Other DoD applications include joining large ceramic gun barrel liners and bondingcomposite ceramic armor plates to metal. Commercially, the ability to directly join ceramicceramicand ceramic-metal structures would make applications for power turbines, industrialthermal processing equipment, ceramic tooling, x-ray targets, and high temperature moldspossible.

Keywords:
CMC, nickel base superalloys, exothermic brazing, joining, attachment, jet engine

In this Phase II effort MRi and its partners are teaming with GE, Boeing and Goodrich develop exotherm assisted bonding (EAB) technology as a cost effective method to join and attach ceramic composites to metals for application in the fabrication of CMC aircraft engine and missile components. This Phase II program is a technology demonstration effort aimed at developing MRi’s innovation which is based on the use of specially prepared nano-phase exothermic particulate materials in combination with polycarbosilane (PCS) to produce composite joints that bond SiC:SiC to metallic structures. The Phase II program will continue to investigate the use of a range of exotherm assisted bonding (EAB) materials, teamed with Ohio Aerospace Institute (OAI) and Exotherm Corporation. Phase II investigations will develop high energy density, refractory nano-phase exothermic fillers and conduct experiments that join melt infiltrated SiC:SiC to Waspalloy and IN718. Nano-phase exothermic filler mixtures will be prepared and used to join flat overlap SiC:SiC and superalloy joints that are representative in size and geometry to those in actual components. Joints will be tested from R.T up to 2,000ºF and selected samples will be subjected to mechanical testing and thermal burner rig testing at NASA-Glenn Research Center.

Keywords:
Nano-Phase, Exothermic Particulates, Bonding Of Cmc's To Metals, Melt Infiltrated Sic:Sic