Abstract: An example system includes at least one acoustic sensor configured to generate at least one time-dependent acoustic data signal indicative of an acoustic signal generated by a cold spray system performing a process possessing a plurality of process attributes, and a computing device including an acoustic data signal processing module configured to receive the at least one time-dependent acoustic data signal, and transform the at least one time-dependent acoustic data signal to a frequency-domain spectrum, wherein each process attribute of the plurality of process attributes is associated with at least one respective frequency band, and a correlation module configured to determine a process attribute of the plurality of process attributes by identifying at least one characteristic of the frequency-domain spectrum.

Abstract: An example system includes at least one acoustic sensor configured to generate at least one time-dependent acoustic data signal indicative of an acoustic signal generated by an atomization system performing a process possessing a plurality of process attributes, and a computing device including an acoustic data signal processing module configured to receive the at least one time-dependent acoustic data signal, and transform the at least one time-dependent acoustic data signal to a frequency-domain spectrum, wherein each process attribute of the plurality of process attributes is associated with at least one respective frequency band, and a correlation module configured to determine a process attribute of the plurality of process attributes by identifying at least one characteristic of the frequency-domain spectrum.

Abstract: An example system includes at least one acoustic sensor configured to generate at least one time-dependent acoustic data signal indicative of an acoustic signal generated by a system performing a fluid transport process possessing a plurality of process attributes. The fluid transport process may include a flow of a fluid along at least one path. The system may further include a computing device including an acoustic data signal processing module configured to receive the at least one time-dependent acoustic data signal, and transform the at least one time-dependent acoustic data signal to a frequency-domain spectrum. Each process attribute of the plurality of process attributes may be associated with at least one respective frequency band. The computing device may include a correlation module configured to determine a process attribute of the plurality of process attributes by identifying at least one characteristic of the frequency-domain spectrum.

Abstract: An example system includes at least one acoustic sensor configured to generate at least one time-dependent acoustic data signal indicative of an acoustic signal generated by an engine performing a process possessing a plurality of process attributes, and a computing device including an acoustic data signal processing module configured to receive the at least one time-dependent acoustic data signal, and transform the at least one time-dependent acoustic data signal to a frequency-domain spectrum, wherein each process attribute of the plurality of process attributes is associated with at least one respective frequency band, and a correlation module configured to determine a process attribute of the plurality of process attributes by identifying at least one characteristic of the frequency-domain spectrum.

Abstract: An example system includes at least one acoustic sensor configured to generate at least one time-dependent acoustic data signal indicative of an acoustic signal generated by a system performing a powder transport process possessing a plurality of process attributes. The powder transport process may include a flow of a powder stream along at least one path. The system may further include a computing device including an acoustic data signal processing module configured to receive the at least one time-dependent acoustic data signal, and transform the at least one time-dependent acoustic data signal to a frequency-domain spectrum. Each process attribute of the plurality of process attributes may be associated with at least one respective frequency band. The computing device may include a correlation module configured to determine a process attribute of the plurality of process attributes by identifying at least one characteristic of the frequency-domain spectrum.

Abstract: An example system includes at least one acoustic sensor configured to generate at least one time-dependent acoustic data signal indicative of an acoustic signal generated by an nuclear power plant performing a process possessing a plurality of process attributes, and a computing device including an acoustic data signal processing module configured to receive the at least one time-dependent acoustic data signal, and transform the at least one time-dependent acoustic data signal to a frequency-domain spectrum, wherein each process attribute of the plurality of process attributes is associated with at least one respective frequency band, and a correlation module configured to determine a process attribute of the plurality of process attributes by identifying at least one characteristic of the frequency-domain spectrum.

Abstract: An additive manufacturing technique may include depositing, via a filament delivery device, a filament onto a surface of a substrate. The filament includes a binder and a powder including at least one metal or alloy and at least one braze alloy. The technique also includes sacrificing the binder to form a preform. The technique also includes sintering the preform to form a component including the at least one metal or alloy and the at least one braze alloy.

Abstract: In some examples, a method of forming an article for a gas turbine engine, the method comprising depositing a powder to form a protective coating on a leading edge of an airfoil substrate. The deposited powder includes carbide particles in a metal matrix and the carbide particles in the powder have an average particle size of about 1 micron or less. The protective coating on the leading edge of the airfoil substrate includes the carbide particles in the metal matrix.

Abstract: A suspension plasma spray deposition system comprising a suspension plasma spray device configured to deposit coating material on a surface of a component. The surface of the component includes a plurality of apertures. The system further includes a fluid flow system configured to flow fluid through the plurality of apertures in the surface of the component to reduce deposition of coating material in plurality of apertures. The fluid flow through each respective aperture of the plurality of apertures in the surface of the component is between about 0.095 and about 0.200 cubic feet per minute (cfm).

Abstract: An article may include a substrate and a coating system on the substrate. The coating system may include a thermal barrier coating (TBC) layer and a CMAS resistant layer on the TBC layer. The CMAS layer includes a rare-earth (RE) monosilicate composition including a plurality of RE metal cations, wherein RE monosilicate composition is configured to react with CMAS to form a reaction product including a RE apatite phase with a RE2O3·SiO2 composition, wherein the RE of the RE2O3·SiO2 composition includes at least one of the plurality of RE metal cations of the RE monosilicate.

Abstract: An article may include a substrate defining at least one at least partially obstructed surface. The substrate includes at least one of a ceramic or a ceramic matrix composite. The article also may include a multilayer, multi-microstructure environmental barrier coating on the at least partially obstructed substrate. The multilayer, multi-microstructure environmental barrier coating includes a first layer comprising a rare earth disilicate and a substantially dense microstructure; and a second layer on the first layer. The second layer includes a columnar microstructure and at least one of a rare earth monosilicate or a thermal barrier coating composition comprising a base oxide comprising zirconia or hafnia; a primary dopant comprising ytterbia; a first co-dopant comprising samaria; and a second co-dopant comprising at least one of lutetia, scandia, ceria, gadolinia, neodymia, or europia.

Abstract: An article may include a substrate including a ceramic matrix composite (CMC); a composite coating layer including a first coating material that includes a rare-earth disilicate and a second coating material that includes at least one of a rare-earth monosilicate, a CMAS-resistant material, or a high-temperature dislocating material, where the second coating material forms a substantially continuous phase in the composite coating layer.

Abstract: In general, techniques are described for fused filament fabrication of abradable coatings. An additive manufacturing system comprising a substrate defining a major surface, a filament delivery device, and a computing device may be configured to perform various aspects of the techniques. The computing device may be configured to control the filament delivery device to deposit a filament on the substrate, the filament including a powder and a binder, wherein the binder is configured to be substantially removed from the filament and the powder includes a metal or alloy configured to be sintered to form an abradable layer.

Abstract: An article that includes a substrate; a first layer including yttria and zirconia or hafnia, where the first layer has a columnar microstructure and includes predominately the zirconia or hafnia; a second layer on the first layer, the second layer including zirconia or hafnia, ytterbia, samaria, and at least one of lutetia, scandia, ceria, neodymia, europia, and gadolinia, where the second layer includes predominately zirconia or hafnia, and where the second layer has a columnar microstructure; and a third layer on the second layer, the third layer including zirconia or hafnia, ytterbia, samaria, and a rare earth oxide including at least one of lutetia, scandia, ceria, neodymia, europia, and gadolinia, where the third layer has a dense microstructure and has a lower porosity than the second layer.

Abstract: In some examples, an article may include a substrate and a coating system on the substrate. The coating system may include a layer comprising a plurality of voids, wherein respective voids of the plurality of voids define respective void volumes; and a nucleating agent within at least some of the respective void volumes of the layer, wherein the nucleating agent is configured to induce crystallization of the molten CMAS. The coating system may include an environmental barrier coating, thermal barrier coating, and/or abradable coating.

Abstract: In some examples, a method comprising: controlling a first ratio of a first liquid to a second liquid to form a first suspension comprising a powder and a first carrier liquid composition comprising at least one of the first liquid or the second liquid; directing the first suspension comprising the first carrier liquid and the powder to a plume of a thermal spray device; forming a first portion of a coating comprising the powder on a substrate from the first suspension; controlling a second ratio of the first liquid to the second liquid to form a second suspension comprising a second carrier liquid composition and the powder; directing the second suspension comprising the second carrier liquid composition and the powder to the plume of the thermal spray device; and forming a second portion of the coating comprising the powder on the substrate from the second suspension.

Abstract: An additive manufacturing technique includes depositing, via a filament delivery device, a filament onto a surface of a substrate. The filament includes a binder and a high entropy alloy powder. The technique also includes sacrificing the binder to form a preform and sintering the preform to form a component.

Abstract: An additively manufactured component that includes a tool with a region having a plurality of overlying metal layers each derived from a metal powder filament. The region has a predetermined yield point selected based on an operation to be performed with the tool.

Abstract: In some examples, an additive manufacturing technique including forming an as-deposited coating on a substrate by depositing a filament via a filament delivery device, wherein the filament includes a sacrificial binder and a powder; removing substantially all the binder from the as-deposited coating; and sintering the as-deposited coating to form a thermal coating; wherein the thermal coating is configured to ablate in response to absorption of energy from an external environment, and wherein the ablation of the thermal coating reduces the energy transferred to the substrate.

Abstract: The disclosure describes articles and techniques that include an airfoil having a hybrid coating system to provide improved particle impact resistance and improve CMAS attack resistance on the pressure side of the airfoil and improved thermal load protection on the suction side of the airfoil. An example article for a gas turbine engine may include a substrate, and a hybrid environmental barrier coating (EBC) including a relatively dense EBC layer on a first portion of the substrate and a relatively porous EBC layer on a second portion of the substrate, where the first portion of the substrate is different from the second portion of the substrate, and wherein at least a portion of the relatively porous EBC layer overlaps at least a portion of the relatively dense EBC layer in an overlap region.