SBIR-STTR Award

Surmets Sinter/HIP process for producing transparent spinel has demonstrated material of much higher strength than has been achieved through our competitors hot press/HIP process. However, our spinel material has also been plagued with inclusions which are optically undesirable and may act as potential flaw sites for mechanical failure. These inclusions are believed to be associated with the starting powder, purchased from Baikowski. Recently, Surmet has developed a process for producing our own optical quality spinel powder, and is currently producing this powder in tens of kilogram sized batches. Importantly, Surmet is able to produce inclusion free spinel material using its own spinel powder, colloidal processing and its Sinter/HIP process. This is a major technical breakthrough for Surmet. We believe that the combination of new powder, colloidal processing and Sinter/HIP will produce inclusion free material that is much stronger than has been achieved by our competitors hot press/HIP process. Furthermore, Surmet is currently bringing a very large HIP (40-in diameter x 60-in long) on-line in the 3rd quarter of 2013 as part of its ongoing Title III program. This puts Surmet in a unique position to be able to produce large high strength spinel windows for the DDG-1000 and other programs.

Benefit:
The biggest demand and opportunity for large size transparent ceramics continues to be in the area of transparent armor, however, the market for Reconnaissance (Recce) windows and sensor domes and windows is also increasing. Spinel is a prime candidate for airborne and shipboard electro-optic sensor applications that operate from the visible through the midwave infrared (3-5 microns). One such application includes the Navys DDG 1000 class destroyer. Other applications include unmanned Recce aircraft. UAV spending is anticipated to double during the next decade from current worldwide expenditures of $5.9 billion annually to $11.3 billion.

Keywords:
Infrared, Infrared, Sensor Window, Reconnaissance Window, High-strength spinel, colloidal processing, magnesium aluminate, Spinel

Spinels combination of extended MWIR transmission and its ability to be produced in large sizes using conventional powder processing techniques, make it the material of choice for many sensor window applications. However, the severe environmental requirements for these applications drive the spinel windows strength requirements well beyond that has been demonstrated using the LiF hot pressing/HIP process. This is the most common method for producing large plates of spinel. By contrast, Surmets spinel is produced by a sinter/HIP process, which has long been known to provide much stronger spinel than hot pressing. During the Phase I effort, Surmet produced spinel blanks of up to 6 0x9D x10 0x9D x0.6 0x9D using its solid state sinter/HIP process. Biaxial flexure strength testing showed that Surmets spinel was significantly stronger (225-245MPa) than the spinel produced by LiF hot pressed/HIP (~100 MPa). The overall objective of the Phase II is to manufacture large spinel windows that meet the strength and optical requirements. Threshold set for part size is at 19 0x9D x27 0x9D x0.6 0x9D , with objective at 30 0x9D x28 0x9D x0.6 0x9D . This effort would leverage Surmets considerable expertise in commercially producing large ALON blanks up to 19 0x9D x36 0x9D size and its very large furnace capabilities to demonstrate commercial production capability for large spinel windows.

Benefit:
The biggest demand and opportunity for large size transparent ceramics continues to be in the area of transparent armor, however, the market for Reconnaissance (Recce) windows and sensor domes and windows is also increasing. Spinel is a prime candidate for airborne and shipboard electro-optic sensor applications that operate from the visible through the midwave infrared (3-5 microns). The applications include unmanned Recce aircraft. UAV spending is anticipated to double during the next decade from current worldwide expenditures of $5.9 billion annually to $11.3 billion.

Keywords:
Spinel, Reconnaissance Window, colloidal processing, High-strength spinel, infrared., magnesium aluminate, Sensor Window