Pigmented coating resists thermal shock
Coating pigment composed of zinc oxide and potassium silicate resists the effects of thermal shock and long exposure to direct sunlight.
Harada, Y.↗
SEARCH · Engineering Papers
Results for “thermal shock”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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The bond stress in a viscoelastic propellant disk during thermal shock
Analysis of bond stress in viscoelastic case bonded solid propellant rocket assembly during thermal shock
Levitsky, M.↗
SNAP 8 refractory boiler development program - Mercury thermal shock testing of 2 1/2-inch-diameter bimetallic joints for SNAP 8 applications Topical report no. 4
Thermal shock testing of coextruded and brazed tubular joints of stainless steel and tantalum for SNAP-8 application
Thompson, S. R.↗
The development of an environmental disturbance model for large space structures after the onset of thermal shock
Expressions for the temperature response across a thin large space structure during and immediately following the onset of thermal shock are obtained as a function of the properties of the material and the solar incidence angle. The thermal gradients induced due to solar radiation heating result in thermal deformation. From the temperature gradient information, expressions are developed for the time history of the thermally induced deflections based on the thermoelastic relationships. The effect of the variation of the solar incidence angle and the variation of the emissivity of the surface is considered. From the deflection time history, a model of the disturbance moments is developed and evaluated for different solar incidence angles.
Hamsath, N.↗
Identification and analysis of factors affecting thermal shock resistance of ceramic materials in solar receivers
An analysis was conducted of the possible modes of thermal stress failure of brittle ceramics for potential use in point-focussing solar receivers. The pertinent materials properties which control thermal stress resistance were identified for conditions of steady-state and transient heat flow, convective and radiative heat transfer, thermal buckling and thermal fatigue as well as catastrophic crack propagation. Selection rules for materials with optimum thermal stress resistance for a particular thermal environment were identified. Recommendations for materials for particular components were made. The general requirements for a thermal shock testing program quantitatively meaningful for point-focussing solar receivers were outlined. Recommendations for follow-on theoretical analyses were made.
Hasselman, D. P. H.↗
Simple, reproducible methods for thermal shock testing of brittle materials
Technique requires radio frequency induction power source, induction furnace and good vacuum system to induce brittle material thermal shock testing.
Rowley, J. C.↗
Strength and thermal shock resistance of porous reaction-bonded silicon nitride by direct nitriding of binder jet additively manufactured silicon
The direct nitridation of binder jet additively manufactured silicon to produce porous silicon nitride was explored. The Taguchi Design of Experiments method was used to systematically study the effect of time, temperature, and nitrogen flow rate on the direct nitriding of binder jet additively manufactured silicon to produce porous reaction-bonded silicon nitride (RBSN). Highly porous (61%) samples with high conversion (99%) to silicon nitride were achieved using a thermal profile that utilized two isothermal holds. Further, it was shown that these samples exhibited thermal shock resistance and a low coefficient of thermal expansion. These results indicate that RBSN is readily achievable through additive manufacturing.
Ceramics↗
Smoother Turbine Blades Resist Thermal Shock Better
Surface treatment increases resistance of turbine blades to low-cycle fatigue. Smoothing removes small flaws where cracks start. Intended for blades in turbines subject to thermal shock of rapid starting. No recrystallization occurs at rocket-turbine operating temperatures.
Czerniak, Paul↗
Silicon nitride: A ceramic material with outstanding resistance to thermal shock and corrosion
The known physical, mechanical and chemical properties of reaction-sintered silicon nitride are summarized. This material deserves interest especially because of its unusually good resistance to thermal shock and corrosion at high temperatures. Two types are distinguished: reaction-sintered (porous) and hot-pressed (dense) Si3N4. Only the reaction-sintered material which is being produced today in large scale as crucibles, pipes, nozzles and tiles is considered.
Huebner, K. H.↗
Evaluation of microcrack thermal shock damage in ceramics: Modeling and experiment
In this paper we present an experimental and theoretical study of the effect of microcrack damage on ceramic properties. For the experimental investigation, ceramic samples of aluminum oxide and reaction bonded silicon nitride (RBSN) are used. Thermal shock treatment from different temperatures up to 1000 C is applied to produce the microcracks. Both surface and bulk ultrasonic wave methods are used to correlate the change of elastic constants to microstructural degradation and to determine the change in elastic anisotropy induced by microcrack damage. For the theoretical investigation, damage mechanics, which relates microstructural damage to material service life and mechanical failure, is used. The change in elastic properties due to microcrack damage calculated from the theoretical model is compared with the experimental results for determination of the applicability of damage theory. It is shown that two independent experimental methods (bulk wave and surface wave) give the same results for shear moduli of damaged ceramics. The experimental results aagree reasonably well with the moduli predicted from the cracked solid model.
Chu, Y. C.↗
A sputtered zirconia primer for improved thermal shock resistance of plasma-sprayed ceramic turbine seals
It is shown that the application of sputtered Y2O3-stabilized ZrO2 (YSZ) primer in plasma-sprayed YSZ ceramic-coated turbine blades results in an improvement, by a factor of 5-6, in the thermal shock life of specimens with a sprayed, porous, Ni-Cr-Al-Y intermediate layer. Species with and without the primer were found to be able to survive 1000 cycles when the intermediate layer was used, but reduced laminar cracking was observed in the specimen with the primer. It is suggested that the sputtered YZS primer-induced properties are due to (1) more effective wetting and adherence of the plasma-sprayed YZS particles to the primer, and (2) the primer's retardation of impinging, molten plasma sprayed particles solidification rates, which result in a less detrimental residual stress distribution.
Bill, R. C.↗
Laboratory-Based Thermal Shock Investigation of Heat Flux Sensors for the Mars 2020 Backshell
In 2012 during the entry, descent, and landing of the Mars Science Laboratory (MSL), the MSL Entry, Descent, and Landing Instrumentation (MEDLI) sensor suite was collecting in-flight heatshield pressure and temperature data. The data collected by the MEDLI instruments has since been used for reconstruction of vehicle aerodynamics, atmospheric conditions, aerothermal heating, and Thermal Protection System (TPS) performance as well as material response model validation and refinement. The Mars Entry, Descent, and Landing Instrumentation 2 (MEDLI2) sensor suite for the Mars 2020 heatshield and backshell is being designed to expand on the measurements and knowledge gained from MEDLI. Similar to MEDLI, MEDLI2 will measure the pressure and temperature of the heatshield. MEDLI2 will additionally measure the temperature, pressure, total heat flux, and radiative heat flux on the backshell. Since the backshell instrumentation is new to MEDLI2, Do No Harm (DNH) testing was conducted on instrumented backshell TPS (SLA-561V) panels. The panels consisted of four pressure port holes, one Mars Entry Atmospheric Data System (MEADS) pressure port plug, one MEDLI2 Integrated Sensor Plug (MISP) thermal plug, and one heat flux sensor. DNH testing was conducted to ensure the performance of the TPS was not degraded due to sensor integration and to characterize any TPS performance changes. The testing consisted of environmental testing— vibration, shock, thermal vacuum (TVAC) cycling— and bounding aerothermal (arc jet) testing.
Miller, R. A.↗
Shock-thermal history of Kapoeta howardite matter on data of thermoluminescence analysis of individual mineral grains
The artificially induced thermoluminescence (TL) was measured in OPx grains from Kapoeta howardite. The TL glow curves for individual OPx grains are significantly distinguished from each other both by their shape and TL sensitivity; five groups of OPx grains were characterized. The observed variety of glow curves of OPx grains could be caused by their distinct shock-thermal events at the regolith stage of meteorite parent body formation.
Ivliev, A. I.↗
Thermal conductivity and thermal shock qualities of zirconia coatings on thin gage Ni-Mo-C metal
Thermal conductivity and shock resistance of flame and plasma sprayed zirconia coatings on Ni-Mo-C metal
Buckley, J. D.↗
Rocket nozzle thermal shock tests in an arc heater facility
A rocket motor nozzle thermal structural test technique that utilizes arc heated nitrogen to simulate a motor burn was developed. The technique was used to test four heavily instrumented full-scale Star 48 rocket motor 2D carbon/carbon segments at conditions simulating the predicted thermal-structural environment. All four nozzles survived the tests without catastrophic or other structural failures. The test technique demonstrated promise as a low cost, controllable alternative to rocket motor firing. The technique includes the capability of rapid termination in the event of failure, allowing post-test analysis.
Painter, James H.↗
Ar-40/Ar-39 age of the Shergotty achondrite and implications for its post-shock thermal history
Ar-40/Ar-39 measurements are used to determine the age of the Shergotty achondrite and the chronology of the shock event responsible for the complete conversion of its plagioclase to maskelynite is discussed. Apparent ages are found to vary between 240 and 640 million years for the whole rock sample, with a plateau age of 254 million years for a maskelynite separate. The Rb-Sr age of 165 million years determined by Nyquist at al (1978) suggests that the maskelynite as well as the whole rock was incompletely degassed. Argon diffusion characteristics indicate a post-shock cooling time greater than 1000 years and a burial depth greater than 300 m for a thermal model of a cooling ejecta blanket of variable thickness. It is concluded that the shock event which degassed the argon and reset the Rb-Sr systematics occurred between 165 and 250 million years ago when the parent body experienced a collision in the asteroid belt.
Bogard, D. D.↗
Thermal shock in a circumferentially cracked hollow cylinder with cladding
An theoretical analysis is presented which demonstrates the effect of cladding on the thermal resistance of a circumferentially cracked hollow cylinder. The cladding is assumed to be bonded to the inner wall of the hollow cylinder. The axisymmetric circumferential crack may be either embedded in the cylinder wall or may be an edge crack which passes through the clad and opens into the inner wall of the hollow cylinder. The problem is formulated mathematically and a solution is found which is in the form of a single integral equation. The integral equation is solved numerically and yields estimates of transient temperature distributions, thermal stresses in the uncracked cylinder, and stress intensity factors as a function of time for various cladding thickness to cylinder wall thickness ratios. It is shown that yielding of the clad under certain conditions can result in a reduction in the magnitude of the stress intensity factor for the crack tip in the elastic base material.
Nied, H. F.↗
Reinforced thermal-shock resistant ceramics
Composite material, made by dispersing short tungsten-rhenium fibers randomly throughout zirconium oxide, is highly resistant to oxidizing environments at temperatures above 2000 degrees F. This reinforced ceramic is also thermal stress resistant.
Crump, D. N.↗