Oxide/Metal Composite Infiltration for Near-Net-Shape Components
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Solution Overview
Problem
Existing methods struggle to produce high-melting, thermally, chemically, and mechanically robust ceramic/refractory metal composites in complex, near-net shapes for high-temperature applications like hypersonic vehicles and energy conversion devices, while being cost-effective.
Innovation Solution
A displacive compensation of porosity (DCP) process is used to infiltrate a porous preform with a fluid reactant containing yttrium, reacting with niobium oxide to form an yttria/niobium composite, filling pores and maintaining near-net shape, utilizing a displacement reaction that increases solid volume to compensate for porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sintering and machining methods are used to produce ceramic/refractory metal composites, then manufacturing precision can be achieved, but production cost increases and sintering shrinkage occurs
Solution Approach 1:
The porous preform is prepared in advance with a controlled pore structure that will transform into the desired final shape. The displacement reaction is designed to occur within this preform structure, allowing the final composite to achieve near-net shape directly from the reaction process, eliminating subsequent machining operations
Solution Approach 2:
The invention changes the physical state parameters of the reactants - using a liquid or gaseous displacing metal that transforms into a solid metal phase during the displacement reaction. This phase change enables pore filling and volume compensation, achieving dimensional accuracy without conventional sintering shrinkage
2Manufacturing precision
If displacement reaction is used to fill pores and maintain near-net shape, then sintering shrinkage is avoided, but manufacturing complexity increases
Solution Approach 1:
The displacing metal reactant self-generates the pressure and fluid flow needed to infiltrate the porous preform through the displacement reaction itself. The reaction products automatically fill the pores and maintain the near-net shape without requiring external pressure equipment or complex process control
Solution Approach 2:
The porous preform structure serves as an intermediary that guides the displacement reaction. The preform's pore network acts as a template that directs the infiltrating displacing metal and controls the reaction progression, simplifying the overall process by providing a built-in reaction pathway
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process produces thermally, chemically, and mechanically robust oxide/metal composites with high melting temperatures and thermal shock resistance, suitable for high-temperature environments, while being cost-effective and avoiding sintering shrinkage and machining costs.
Implementation Method 1
The yttrium of the fluid reactant is capable of displacing the niobium cations in the solid oxide reactant to produce at least yttria (yttria is used to refer herein to yttrium oxide) as a solid oxide reaction product and niobium metal as a solid metal reaction product
Implementation Method 2
The porous preform is then infiltrated with the fluid reactant to react the yttrium of the fluid reactant with the niobium oxide of the solid oxide reactant
Implementation Method 3
the reaction product volume is greater than the solid volume lost by the solid oxide reactant as a result of the reaction of the yttrium and the niobium oxide
Data Source
AI summary
Methods for producing oxide/metal composite components for use in high temperature systems, and components produced thereby. The methods use a fluid reactant and a porous preform that contains a solid oxide reactant. The fluid reactant contains yttrium as a displacing metal and the solid oxide reactant of the preform contains niobium oxide, of which niobium cations are displaceable species. The preform is infiltrated with the fluid reactant to react its yttrium with the niobium oxide of the solid oxide reactant and produce an yttria/niobium composite component, during which yttrium at least partially replaces the niobium cations of the solid oxide reactant to produce yttria and niobium metal, which together define a reaction product. The pore volume of the preform is at least partially filled by the reaction product, whose volume is greater than the volume lost by the solid oxide reactant as a result of reacting yttrium and niobium oxide.