# US 10,371,588 B2 · High resolution strain gages for ceramic matrix composites and methods of manufacture thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,588 B2 - Document ID: US10371588B2 - Status: Granted - Kind: B2 - Application number: 15/640,348 - Filed: 2017-06-30 - Published: 2018-01-04 - Granted: 2019-08-06 - Earliest claimed: 2016-07-01 - Assignees: Rhode Island Council on Postsecondary Education - Applicants: Rhode Island Council on Postsecondary Education - Inventors: Otto Gregory; John T. Rhoat; Kevin Rivera - Web page: https://patentgrep.com/patent/US10371588B2 ## CPC - G01L 1/2281: {for temperature variations} - G01L 1/2293: {of the semi-conductor type} - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) ## Abstract Strain gages for use with ceramic matrix composites (CMCs), and methods of manufacture therefore. The strain gages use the CMC as a strain element. For semiconductor CMCs, for example SiC fiber-reinforced SiC CMC, their large gage factor enables high sensitivity, high accuracy strain measurements at high temperatures. By using a single elemental metal such as platinum, or another high temperature conductive material, the strain gages can operate at temperatures over 1600° C. The conductive material is preferably deposited on a dielectric or insulating layer, and contacts the CMC substrate through openings in that layer. The materials can be deposited using thin film vacuum techniques or thick film techniques such as pastes or inks. The strain gages can be configured to measure only the mechanical strain independent of the apparent or thermal strain. The strain gages can be incorporated into a bulk CMC structure during layup, and can optionally measure the strain of only desired fiber weave orientations. ## Claims ### Claim 1 A strain gage comprising: a ceramic matrix composite (CMC) layer; a film deposited on a portion of said CMC layer; and a conductive material deposited partially on said film and partially on said CMC layer, said conductive material transmitting a change in an electrical property of said CMC layer when said CMC layer is strained. ### Claim 2 (depends on 1) The strain gage of claim 1 capable of operating at greater than 1000° C. ### Claim 3 (depends on 1) The strain gage of claim 1 capable of operating at greater than 1600° C. ### Claim 4 (depends on 1) The strain gage of claim 1 wherein said conductive material is a single elemental metal. ### Claim 5 (depends on 4) The strain gage of claim 4 wherein said metal is platinum. ### Claim 6 (depends on 1) The strain gage of claim 1 wherein said conductive material is indium tin oxide. ### Claim 7 (depends on 1) The strain gage of claim 1 wherein said film comprises a dielectric, insulating, or planarizing film. ### Claim 8 (depends on 7) The strain gage of claim 7 wherein said film comprises mullite. ### Claim 9 (depends on 7) The strain gage of claim 7 wherein said conductive material contacts said CMC layer through openings in said film. ### Claim 10 (depends on 9) The strain gage of claim 9 comprising an oxygen diffusion barrier deposited on said conductive material in a vicinity of said openings. ### Claim 11 (depends on 10) The strain gage of claim 10 wherein said oxygen diffusion barrier comprises indium oxynitride or indium-tin-oxynitride. ### Claim 12 (depends on 7) The strain gage of claim 7 wherein said conductive material comprises a metal and said strain gage comprises a silicide diffusion barrier deposited between said metal and said CMC layer. ### Claim 13 (depends on 12) The strain gage of claim 12 wherein said silicide diffusion barrier comprises indium tin oxide. ### Claim 14 (depends on 7) The strain gage of claim 7 wherein said conductive material and said film is deposited as a paste, ink, spray, or cement. ### Claim 15 (depends on 14) The strain gage of claim 14 wherein said conductive material and said film is deposited without the use of a vacuum chamber. ### Claim 16 (depends on 14) The strain gage of claim 14 wherein damage to said conductive material or said film is reparable by depositing paste, ink, spray, or cement in situ. ### Claim 17 (depends on 1) The strain gage of claim 1 wherein said conductive material and said film are deposited and patterned using vacuum sputtering and/or photolithography. ### Claim 18 (depends on 1) The strain gage of claim 1 comprising a resistor comprising said conductive material oriented perpendicular to a strain direction of said strain gage. ### Claim 19 (depends on 18) The strain gage of claim 18 wherein said resistor is disposed in series with said strain gage or said resistor forms a second strain gage having said resistor as a strain element. ### Claim 20 (depends on 18) The strain gage of claim 18 wherein said strain gage is capable of measuring mechanical strain independent of apparent or thermal strain. ### Claim 21 (depends on 1) The strain gage of claim 1 wherein said CMC layer comprises a semiconductor. ### Claim 22 (depends on 21) The strain gage of claim 21 wherein said semiconductor is a wide bandgap semiconductor. ### Claim 23 (depends on 21) The strain gage of claim 21 wherein said semiconductor is selected from the group consisting of silicon carbide, boron nitride, and carbon. ### Claim 24 (depends on 21) The strain gage of claim 21 wherein said CMC layer comprises a silicon carbide fiber-reinforced silicon carbide matrix, a carbon fiber-reinforced carbon matrix, or a boron nitride fiber-reinforced boron nitride matrix. ### Claim 25 (depends on 1) The strain gage of claim 1 embedded within a bulk composite structure comprising said CMC layer. ### Claim 26 (depends on 25) The strain gage of claim 25 inserted into said bulk composite structure during layup of said bulk composite structure. ### Claim 27 (depends on 25) A bulk composite structure comprising a plurality of the strain gage of claim 25, wherein said strain gages are electrically connected to only CMC layers comprising a desired fiber weave orientation. ### Claim 28 (depends on 1) The strain gage of claim 1 wherein the response of the strain gage depends on the fiber orientation of the CMC layer.