A hybrid ceramic structure (10), for use in high temperature environments such as in gas turbines, is made from an insulating layer (12) of porous ceramic that is thermally stable at temperatures up to 1700 C bonded to a high mechanical strength structural layer (8) of denser ceramic that is thermally stable at temperatures up to 1200 C, where optional high temperature resistant adhesive (9) can bond the layers together, where optional cooling ducts (11) can be present in the structural layer and where hot gas (14) can contact the insulating layer (12) and cold gas (15) can contact the structural layer (8).

Hybrid ceramic material composed of insulating and structural ceramic layers

An immersion pyrometer having an outer casing comprising a mixture of graphite and a refractory metal oxide for contact with molten metal, an inner sheath enclosed by said outer casing, said inner sheath comprising a closed end metal tube wherein the closed end is in heat transfer contact with said outer casing, and a thermocouple within said inner sheath.

Protective structure for an immersion pyrometer

A hybrid vane ( 50 ) for a gas turbine engine having a ceramic matrix composite (CMC) airfoil member ( 52 ) bonded to a substantially solid core member ( 54 ). The airfoil member and core member are cooled by a cooling fluid ( 58 ) passing through cooling passages ( 56 ) formed in the core member. The airfoil member is cooled by conductive heat transfer through the bond (( 70 ) between the core member and the airfoil member and by convective heat transfer at the surface directly exposed to the cooling fluid. A layer of insulation ( 72 ) bonded to the external surface of the airfoil member provides both the desired outer aerodynamic contour and reduces the amount of cooling fluid required to maintain the structural integrity of the airfoil member. Each member of the hybrid vane is formulated to have a coefficient of thermal expansion and elastic modulus that will minimize thermal stress during fabrication and during turbine engine operation.

Ceramic matrix composite gas turbine vane

A ceramic matrix composite material (CMC) vane for a gas turbine engine wherein the airfoil member (12) and the platform member (14) are formed separately and are then bonded together to form an integral vane component (10). Airfoil member and the platform member may be bonded together by an adhesive (20) after being fully cured. Alternatively, respective joint surfaces (16,18) of the green body state airfoil member and platform member may be co-fired together to form a sinter bond (30). A mechanical fastener (38) and/or a CMC doubter (42) may be utilized to reinforce the bonded joint (40). A matrix infiltration process (50) may be used to create or to further strengthen the bond.

Ceramic matrix composite turbine vane

A segmented abradable ceramic coating system having superior abradability and erosion resistance is disclosed. The system includes a duct segment having a metallic substrate, a MCrAlY bond coat on the substrate and a segmented abradable ceramic coating on the bond coat. The segmented abradable ceramic coating includes a base coat foundation layer, a graded interlayer and an abradable top layer for an overall thickness of preferably about 50 mils (1.270 mm). The coating is characterized by a plurality of vertical microcracks. By precisely controlling the deposition parameters, composition of the layers and layer particle morphology, segmentation is achieved, as well as superior abradability and erosion resistance.

Segmented abradable ceramic coating

A composite laminate capable of exposure to high temperature differentials without damage, comprising a first layer, a second layer and an intermediate web interface layer of a low modulus metallic low density structure having a high melting point. The first layer is secured to the low modulus structure directly or through an intermediate composite layer, and the second layer is bonded or secured to the intermediate low modulus layer. The thermal strains caused by a temperature differential between the first and second layers are taken up without harmful effect by the intermediate low modulus web layer.

Method of attaching ceramics to metals for high temperature operation and laminated composite

A ceramic-metal composite laminate capable of exposure to high temperature differentials without damage, consisting of an inner ceramic layer, an outer metal layer and an intermediate interface layer of a low modulus metallic low density structure having a high melting point. The ceramic layer is secured to the low modulus structure directly or through an intermediate ceramic-metal composite, and the outer metal layer is brazed to the intermediate low modulus layer. Thermal strains caused by a temperature differential between the inner and outer layers are taken up without harmful effect by the intermediate low modulus layer.

Robert P. Tolokan

Papers

Method of attaching ceramics to metals for high temperature operation and laminated composite

Ceramic-metal laminate