Sample Surface Temperature Research Articles

Deformation Heat in Tension of Steel Elements

The purpose of the work is an approximate computational and experimental assessment of the specific energy intensity and heat generation at various stages of the material’s operation when the sample is stretched. The paper discusses an approximate method for estimating the specific energy intensity and heat generation at four stages of tensile deformation of a steel sample. Finite element modeling of the work of the manufactured sample under elastic-plastic tension was performed in the ANSYS multifunctional software package. The load in the digital model of the sample was applied according to the full-scale test program. The experiment used flat samples in accordance with GOST 1497, a WAW-1000 testing machine with a 100T microcomputer, and a testo 875i thermal imager with a temperature sensitivity of 0.05 °C at 30 °C. We compared the obtained values on graphs of full-scale tests and a digital model of the samples, identifying critical points and deviation values. Phased loading revealed that the development of destruction occurs on the descending branches and is accompanied by the gradual development of local instability of plastic deformation in the form of a “neck”. It is shown that the heating temperature of the tensile metal can be calculated using the formulas proposed in the paper or by calculation using the ANSYS software package. The test results showed that the surface temperatures of the samples at each stage differ significantly. Four main areas were identified on the graph of changes in the sample surface temperature at a point. An analysis of the existing database of measuring instruments and the ability to obtain and process data was carried out. Experimental values of surface temperatures during continuous quasi-static deformation exceed their calculated values (up to 5 times). The kinetics of changes in the temperature field of the sample surface was carried out using thermographic instruments.

NIR-triggered arsenic-loaded layered double hydroxide-based films for localized thermal synergistic chemotherapy

Portal vein tumor thrombus (PVTT) formed by cancer cell invasion is a major cause of high mortality in hepatocellular carcinoma (HCC), and the formation of thrombus will be accelerated by bacterial colonization on the surface of the implant after surgery. In this work, Polypyrrole-coated arsenic-loaded layered double hydroxide films were in situ constructed on the nickel-titanium alloy for the efficient killing of tumour cells by thermo-therapeutic synergistic chemotherapy. The good near-infrared photothermal conversion ability of polypyrrole enables the sample surface temperature to be raised to about 51 °C at a low photothermal power (0.5 w/cm2), while the elevated temperature could further accelerate the release of drug arsenic. In addition, when NIR light is not applied, the polypyrrole coating also cleverly acts as a “barrier layer” to reduce the natural release of arsenic in normal tissues to avoid toxicity issues. In vivo and in vitro experiments have demonstrated that the platform exhibits excellent antitumor and antibacterial abilities. In contrast to the systemic toxicity issues associated with systemic circulation of nanotherapeutic drugs, this in situ functional film is expected to be used in localised interventions for precise drug delivery, and is also more suitable for surgical treatment scenarios in PVTT surgeries.

Experimental investigation on the high-temperature corrosion of 12Cr1MoVG boiler steel in waste-to-energy plants: Effects of superheater operating temperature and moisture

Waste-to-energy (WTE) technology via municipal solid waste incineration (MSWI) have developed very rapidly with the advantages of achievement on waste disposal and energy conversion. This technology is developing towards higher capacity and efficiency. Therefore, the operation parameters of WTE boilers must be improved. However, higher steam parameters means higher surface temperature of exchange tube in superheaters and reheaters in WTE boilers, resulting higher risk of engineering failure due to high-temperature corrosion. Additionally, the incineration of MSW releases flue gas with a high content of corrosive species and water vapor, which can cause severe high-temperature corrosion. This experimental investigation details the effect of surface temperature and water vapor concentration on the high-temperature corrosion behavior of 12Cr1MoVG boiler steel under an atmosphere mimicking MSWI. The corrosion test environment consists of high temperature, ash deposit and simulated flue gas of waste incineration according to a real WTE boiler. The experiment was conducted using a two-zone bench-scale tube furnace with a gas temperature of 600℃ and the sample temperatures of 380℃, 430℃, and 480℃. For the investigation of water vapor concentration effect, 18 % vol and 23 % vol were set up in this study. After 240 hours of exposure, the corrosion weight curves illustrated that the corrosion kinetics was highly dependent on the surface temperature of corrosion samples. Furthermore, an increase in water vapor concentration exacerbated the high-temperature corrosion. XRD analysis identified the corrosion products as metal chlorides and metal oxides. Cross-sectional SEM images and EDS analysis revealed that an increase in water vapor accelerated the corrosion rate of the steel samples due to chromium dilution behavior.

The Use of Artificial Neural Network for Predicting the Thermal Conductivity of Cement Based Mortar with Natural Zeolites

Zeolites, in their natural state, have been used in construction materials since ancient times. The pozzolanic activity of zeolites and their use as supplementary cementitious materials has been investigated over the past three decades. The indoor comfort provided by a modern life style comes at a cost of consuming enormous amounts of energy. Materials with improved insulation properties are continuously researched and the use of zeolites showing encouraging results. The paper presents experimental results obtained on different cement-based mortar mixes incorporating natural zeolites. The main parameters of the research were: substitution of cement and sand by natural zeolites, three different replacement percentages for cement and sand (10%, 20% and 30%) and the curing age of mortar specimens (14 days, 21 days and 28 days). An artificial neural network (ANN) was developed to predict the values of the thermal conductivity by taking into account parameters such as density, humidity and surface temperature of the mortar samples. The ANN was able to accurately predict the experimental results for the thermal conductivity of cement-based mortars with natural zeolites.

Phase evolution during conventional and reactive flash sintering of (Mg,Ni,Co,Cu,Zn)O via in situ X‐ray diffraction

AbstractReactive flash sintering (RFS) enables the simultaneous synthesis and sintering of ceramics and has been shown to affect the reaction pathway of different materials. Herein, in situ synchrotron X‐ray diffraction (XRD) is used to investigate the (Mg,Ni,Co,Cu,Zn)O entropy‐stabilized oxide formation during: (i) conventional heating and (ii) RFS under current rate‐controlled mode. The same reaction pathway is verified in both instances: the starting rock‐salt (RS), spinel (Co3O4), tenorite (CuO), and wurtzite (ZnO) phases transform into a single RS phase with a (1 1 1) to (2 0 0) intensity ratio of 0.67, consistent with a random distribution of the cations into the structure. Pt lattice peak shift from the XRD patterns is used as standard to monitor the sample surface temperature, revealing a strong endothermic reaction during the RS single‐phase formation (Pt peaks shift toward higher angles while increasing sample temperature/current density). In RFS, the single‐phase RS structure is formed in just 60 s at a furnace temperature of 600°C and a current rate of 220 mA mm−2/min. Therefore, RFS greatly accelerates the synthesis of (Mg,Ni,Co,Cu,Zn)O, however, it does not play a role in the reaction pathway for this material formation.

Analysis of the Effect of Temperature on the Ultimate Strength of Refractory Materials

The energy efficiency of high-temperature batch aggregates largely depends on the modes of their heating and cooling. The modes of heating and cooling of aggregates in which thermal stress does not exceed the critical values of the ultimate strength of the refractories make it possible to increase their service life. The increase in the service life of refractories will lead to a reduction in the number of lining repairs and a decrease in the specific consumption of refractory materials per ton of technological product. Shorter warm-up and cool-down times result in lower energy consumption. Reducing the time for variable modes for casting ladles increases their turnover (the number of melt discharges into the ladle per day). Increasing ladle turnover not only reduces the number of ladles but also improves the economic performance of the enterprise. The ultimate strength of the refractory material significantly affects the rate of temperature change during heating and cooling of the refractory masonry. The purpose of this research is to study the dependence of the ultimate compression and tensile strengths of chamotte materials of the ShKU brand on temperature. The determination of the compression and tensile strengths was carried out on new samples of refractory materials as well as on samples of refractories that were in operation until the intermediate repair. To determine the ultimate compression strength of chamotte refractories, the standard technique for axial compression of the test specimen until its destruction was used. To determine the ultimate tensile strength, a three-point bending test was used with additional control of the surface temperature of the test sample during the test. The ultimate compression strength of chamotte refractories of the ShKU-32 brand increased for the new refractories by a maximum of 44%. For refractories that were in operation until the intermediate repair, the ultimate compression strength increased by a maximum of 56%. The value of the ultimate tensile strength at elevated temperatures turned out to be higher than the value at a temperature of 20 °C. For new refractories, the maximum ultimate tensile strength is 25% higher than the ultimate tensile strength under normal conditions. For refractories that were in operation until the intermediate repair, the maximum ultimate tensile strength increased by 24%. The obtained results can be used to increase the rate of heating or cooling of linings.

Dielectric and physico-chemical behavior of single thermally thick wood blocks under microwave assisted pyrolysis

Pyrolysis of thermally thick beech wood blocks with a size of around 2.5 × 8 × 6 cm3 (width × length × height) was carried out in a lab scale microwave reactor with a frequency of 2.45 GHz, operated, both, at 300 W and 600 W under inert conditions, using N2 at around 400 mbar absolute pressure. The microwave cavity had a size of 20 × 20 × 20 cm3. The specific energy supply referred to the untreated wood block was 4–8 W/g, with slight variations depending on the initial water content. The mass loss and the reflected microwave power were in-situ monitored during the experiments. The sample surface and chamber temperatures were measured with a pyrometer and a thermocouple, respectively. Physico-chemical and dielectric properties of the produced solids were investigated and compared to those of chars produced under conventional pyrolysis using the same raw materials. It is shown that the complex dielectric permittivity of the solid products changed drastically during the pyrolysis process, with increasing heating properties as the conversion process evolved. This was easily achieved using 600 W without susceptors. However, 300 W was not enough to achieve a high conversion degree, independently of the irradiation time. This, together with the physico-chemical analyses of the solids, hinted to the importance of the transport kinetics in thermally thick materials, although further investigation is still required.

Determining thermodynamic temperature of sample surface based on area ratio of photoelectron spectrum

The Fermi–Dirac (FD) distribution describes the occupancy of electronic states in a material at thermal equilibrium as a function of the thermodynamic temperature. By measuring the electron energy distribution using photoelectron spectroscopy, we can obtain the FD distribution and determine the thermodynamic temperature. This study proposes a method for determining the thermodynamic temperature, which involves calculating the area ratio between the photoelectron spectra above and below the Fermi level. This thermometric technique offers several advantages, including surface selectivity, noncontact measurement, and coordination with other measuring devices commonly used in surface analysis and nanoscale measurements under ultrahigh vacuum conditions. In this study, we measured the photoelectron spectra near the Fermi level on an Au (110) surface at three different temperatures: liquid nitrogen, liquid helium, and room temperatures. Using the area ratio method, we successfully determined the thermodynamic temperatures with an accuracy of less than 1 K.

Enhancement of infrared stealth performance of ultra-high molecular weight polyethylene-based composites through the multilayer structural construction

According to the infrared stealth mechanism, combining the low emissivity material and temperature control material is an effective way to improve the infrared stealth performance. In this paper, ultra-high molecular weight polyethylene (UHMWPE)-based multilayer composites with low emissivity and thermal conductivity are prepared through the combination of the low emissivity layers and the thermal insulation layers. The infrared stealth performance of the composites is varied by changing the layer numbers and the thickness of the functional layers as well as the structural design. And the orientation of the low emissivity fillers is realized to further reduce the emissivity of the low emissivity layers. The infrared emissivity of the low emissivity layer is as low as 0.297 and 0.247 at 3–5 μm and 8–14 μm, respectively, which is 25.9% and 46.4% lower than that before modification. The surface temperature of the multilayer sample reaches 26.8 °C after being placed on a 60 °C hot stage for 30 min, exhibiting excellent infrared stealth performance. Meanwhile, the density of the sample is 0.48 g/cm3, and the thickness is 2.8 mm, which is permissible for the infrared stealth applications.

Enhanced Optical–Thermal Performances of High-Power LED by Plated Copper on Thick Film Ceramic Substrate

Thick printed ceramic substrate (TPC) is a promising technique for the packaging of high-power light-emitting diode (LED). Nevertheless, the incorporation of glass phase and voids in the sintered Ag layer decrease the electrical conductivity and heat dissipation of TPC substrate, which contributes to an increase in the junction temperature of LED. This article demonstrates a novel packaging design to plate copper on the sintered Ag layer of TPC substrate, which was applied to enhance the optical–thermal performances of high-power LED. After plating, the copper layers are well bonded with the Ag layer and the sheet resistance decreases rapidly. With the plated copper on thick film (PCTF) substrate package, the total thermal resistance is 17.45% lower than that with TPC package, while the junction temperature change of LED samples is 8.04 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> C and 9.92 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> C, respectively. Moreover, the surface temperature of LED sample packaged with PCTF is 11.16% lower than that with TPC at the working current of 1600 mA, and the optical power is 4.79% and 3.2% higher at the working current of 400 and 1200 mA, respectively. The results demonstrate that the optical–thermal performances of LED are enhanced by using the PCTF substrate due to its excellent heat dissipation.

Bio-PCM to enhance dynamic thermal properties of dry-assembled wooden walls: Experimental results

The lightweight features of dry-assembled wooden walls make the building envelopes not suitable for significantly limiting energy demands. Natural Phase Change Materials (bio-PCM) can be used to enhance the buildings thermal mass preserving the structures sustainability. For this purpose, an experimental campaign was carried out on different configurations of wooden walls, installable both vertically and horizontally, and in which PCM can face both internal and external environments. Preliminary, transient simulations were conducted to identify the suitable PCM melting temperature and the best allocation that conciliates winter and summer needs. Successively, experimental tests allowed for thermally characterizing the wall through dynamic indices, since standardized procedures cannot be employed in the presence of PCMs. At an annual level, energy results showed that a bio-PCM with a melting temperature of 23 °C inserted in the internal side of the wooden wall is preferable, whereas PCMs on both sides produce marginal improvements. Experimentally, a single layer of bio-PCM on the inner side produced a decrement factor of 0.032 (−81%) and a time-lag increase of 2 h when compared with the base case without PCM, whereas the periodic thermal transmittance reduced from 0.148 W/m2K to 0.091 W/m2K. When bio-PCMs are allocated in both the sample sides, a further time-lag increase of 1.6 h and a limitation of the periodic thermal transmittance to 0.086 W/m2K was observed. Conversely, an increase of the decrement factor to 0.049 was detected, due to a negative interference of the PCM melting and solidification processes on the sample surface temperatures. Therefore, in these circumstances experimental data could define unreliable decrement factors for the considered envelope component.

Microwave hybrid and conventional sintering of Al2O3 and Al2O3/ZrO2 multilayers fabricated by aqueous tape casting

AbstractIn this study, microwave hybrid sintering and conventional sintering of Al2O3‐ and Al2O3/ZrO2‐laminated structures fabricated via aqueous tape casting were investigated. A combination of process temperature control rings and thermocouples was used to measure the sample surface temperatures more accurately. Microwave hybrid sintering caused higher densification and resulted in higher hardness in Al2O3 and Al2O3/ZrO2 than in their conventionally sintered counterparts. The flexural strength of microwave‐hybrid‐sintered Al2O3/ZrO2 was 70.9% higher than that of the conventionally sintered composite, despite a lower sintering temperature. The fracture toughness of the microwave‐hybrid‐sintered Al2O3 increased remarkably by 107.8% despite a decrease in the relative density when only 3 wt.% t‐ZrO2 was added. The fracture toughness of the microwave‐hybrid‐sintered Al2O3/ZrO2 was significantly higher (247.7%) than that of the conventionally sintered composite. A higher particle coordination and voids elimination due to the tape casting and the lamination processes, the microwave effect, the stress‐induced martensitic phase transformation, and the grain refinement phenomenon are regarded as the main reasons for the mentioned outcomes.

Study on the Thermal Distribution Characteristics of a Molten Quartz Ceramic Surface under Quartz Lamp Radiation.

More and more researchers are studying the heat transfer performance of aeronautical materials at high temperatures. In this paper, we use a quartz lamp to irradiate fused quartz ceramic materials, and the sample surface temperature and heat flux distribution were obtained at a heating power of 45~150 kW. Furthermore, the heat transfer properties of the material were analyzed using a finite element method and the effect of surface heat flow on the internal temperature field was investigated. The results show that the fiber skeleton structure has a significant effect on the thermal insulation performance of fiber-reinforced fused quartz ceramics and the longitudinal heat transfer along the rod fiber skeleton is slower. As time passes, the surface temperature distribution tends to stability and reaches an equilibrium state. The surface temperature of fused quartz ceramic increases with the increase in the radiant heat flux of the quartz lamp array. When the input power is 5 kW, the maximum surface temperature of the sample can reach 1153 °C. However, the non-uniformity of the sample surface temperature also increases, reaching a maximum uncertainty of 12.28%. The research in this paper provides important theoretical guidance for the heat insulation design of ultra-high acoustic velocity aircraft.

Compact sample environment for in situ X-ray scattering during spin-coating.

We demonstrate a compact sample environment for the in situ study of crystallization kinetics of thin films on synchrotron beamlines, featuring atmospheric control, automated deposition, spin-coating, and annealing stages. The setup is suitable for studying thin film growth in real time using grazing-incidence X-ray diffraction techniques. Humidity and oxygen levels are being detected by sensors. The spinning stage exhibits low vertical oscillation amplitude (∼3μm at speeds up to 10 000 rpm) and can optionally be employed for antisolvent application or gas quenching to investigate the impact of these techniques, which are often used to assist thin film growth. Differential reflectance spectroscopy is implemented in the spin-coater environment for inspecting thin film thickness and optical properties. The infrared radiation-based annealing system consists of a halogen lamp and a holder with an adjustable lamp-to-sample distance, while the sample surface temperature is monitored by a pyrometer. All features of the sample environment can be controlled remotely by the control software at synchrotron beamlines. In order to test and demonstrate the performance, the crystallization pathway of the antisolvent-assisted MAPbI3 (MA = methylammonium) perovskite thin film during the spinning and annealing stages is monitored and discussed.

Modeling and calibration of micro/nano FBG temperature probe for scanning probe microscopy.

To accurately measure the local temperatures of the micro-nano area, we propose an optical method using a tapered fiber Bragg grating (FBG) probe with a nano tip for scanning probe microscopy (SPM). When the tapered FBG probe senses local temperature through near-field heat transfer, the intensity of the reflected spectrum decreases, along with a broadening bandwidth and a shift in the central peak position. Modeling the heat transfer between the probe and the sample shows that the tapered FBG probe is in a non-uniform temperature field when approaching the sample surface. Simulation of the probe's reflection spectrum reveals that the central peak position shifts nonlinearly with increasing local temperature. In addition, the near-field temperature calibration experiments show that the temperature sensitivity of the FBG probe increases nonlinearly from 6.2 pm/°C to 9.4 pm/°C as the sample surface temperature increases from 25.3°C to 160.4°C. The agreement of the experimental results with the theory and the reproducibility demonstrate that this method offers a promising approach for exploring micro-nano temperature.

Photoelectrochemical and Photovoltaic Performance of As-deposited Ink-based CuInS2 Heterojunction Thin Film

In this report, we demonstrate low-temperature ink-based fabrication of CuInS2-based photoelectrodes for hydrogen production capable of producing photocurrent densities as high as 8.8 mA.cm−2. In this process, molecular ink made of metal chlorides and thiourea dissolved in methanol was spin coated onto Mo-coated soda lime glass substrates. Samples were then placed on a hot plate (sample surface temperature: 250 °C) to induce CuInS2 formation and remove the solvent and by-products. No further processing, such as high temperature sulfurization, was performed. The CuInS2 films were then integrated as photocathode for hydrogen evolution by photoelectrodeposition of Pt nanoparticles. Photocurrent density of 0.4 mA.cm−2 at 0 V vs. RHE was detected from such electrodes. However, samples coated with CdS/ZnO/ITO overlayers forming heterojunction prior to Pt deposition exhibited significant improvement of the photocurrent density, reaching 8.8 mA.cm−2 at 0 V vs. RHE, highlighting the improved charge transfer by the p-n junction formed at the CuInS2/CdS interface. The charge transfer resistance of the CuInS2/CdS/ZnO/ITO-Pt photoelectrode was almost 5 times lower than that of the CuInS2-Pt photoelectrode as revealed by electrochemical impedance spectroscopy analysis. In addition, the onset potential was shifted by ca. 0.45 V toward the anodic direction, reaching 0.75 V vs. RHE. Solar cell made of identical structure (Mo/CuInS2/CdS/ZnO/ITO) showed power conversion efficiency of 2.1% with short-circuit photocurrent density and open circuit voltage of 7.4 mA.cm−2 and 820 mV, respectively.

Influences of Microwave Irradiation on the Physicomechanical Properties and Cerchar Abrasivity Index of Rocks

The research is aimed at exploring the influences of microwave irradiation on the physicomechanical properties and Cerchar abrasivity index (CAI) of rocks. For this purpose, basalt collected in Chifeng (the Inner Mongolia Autonomous Region, China) was taken as research objects to carry out microwave irradiation tests for different durations in a multimode cavity. By using the MTS815 mechanical testing machine and the abrasion servo tester of rocks, mechanical tests and Cerchar abrasion tests were conducted before and after microwave irradiation. Changes in the mass, volume, surface fractures, surface temperature, ultrasonic wave velocity, uniaxial compressive strength (UCS), and CAI of the basalt samples before and after microwave irradiation were analyzed. Results show that the surface temperature of basalt samples linearly increases with the duration of microwave irradiation. The volume and fracture coalescence of the rock samples both increase with the prolonging duration of microwave irradiation. The mass, ultrasonic wave velocity, UCS, and CAI of the basalt samples all decrease with the increase in the duration of microwave irradiation. The reduction of the physicomechanical properties and CAI of rocks indicates that microwave irradiation can reduce the wear of rock-breaking tool and thus improve the efficiency of rock breaking.

Исследование антифрикционных и противоизносных свойств смазочных материалов судового назначения, содержащих слоистый модификатор трения

The paper highlights the results of anti-friction and anti-wear tests of samples of lubricating media containing a layered friction modifier - molybdenum diselenide. The main variable test conditions are the load on the test samples, volume concentration of the layered friction modifier in the lubricating oil, preliminary storage time of the lubricating composition before testing. The main evaluation criteria are the mass wear of samples, wear intensity, friction coefficient. Each of the eight test cycles was implemented on a tribotechnical installation of an original design using a cylindrical contact type. The resource indicators transferred from the model conditions of the tests to the real tribological unit “ring-cylinder” of a marine diesel engine 6ChSP 18/22 were evaluated. According to the results of tribological studies, the effect of increasing the load on the model friction unit of the installation, containing a cylindrical wear pair of alloyed gray cast iron, was revealed, as a result of which the mass wear of the annular movable sample increases, and the resource transferred to the real tribological interface of the marine diesel engine “ring-cylinder” decreases in 1.13-1.23 times. The greatest influence on the wear indicators of model samples and the resource transferred to the real “ring-cylinder” interface of a marine diesel engine is the time of preliminary storage of a lubricant composition containing molybdenum diselenide as an additive. It has been proven that the deterioration of anti-friction properties (an increase in the average surface temperature of a segment sample and the friction force) is largely affected by a decrease in the volume concentration of an anti-wear additive in the oil. It has been found out that serious changes in the indicated estimated parameters are valid for the smallest loading step on the samples. General recommendations are formulated for the use of antiwear additives considered in the studies. It has been proved that storing lubricating compositions with additives is possible for a period of no longer than 3-4 days at given volume concentrations in the range of 0.5-1.0%, since if this period is exceeded by 25-40%, the diesel CPG resource may be halved with increased wear of its piston rings and cylinder liners.

Contribution of thermal dissociation during steel nitriding in electron beam plasma

We report the results of measurements of mass-to-charge ion composition of the beam plasma generated by a forevacuum plasma-cathode electron source in a nitrogen atmosphere during electron beam interaction with the surface of a steel sample. It has been found that as the sample surface temperature increases from 540 ℃ to 930 ℃, the fraction of atomic nitrogen ions in the spectrum increases by 4-10%. This increase in atomic nitrogen occurs at the backdrop of decreasing number of molecular nitrogen monoxide ions and is associated with thermal dissociation of its molecules.

Quasi-Static and Dynamic Tensile Behavior of Water-Bearing Sandstone Subjected to Microwave Irradiation

Microwave irradiation on rocks before excavation is an effective method to reduce equipment wear and energy consumption during mechanical cutting. Rock mass excavation is usually carried out in a water-rich environment and exposed to dynamic loads, thus understanding the coupled effects of water content and loading rate on the mechanical behavior of rocks under microwave radiation is essential. In this study, sandstone samples with five levels of water content (from oven-dried to water-saturated) were exposed to microwave irradiation at a power of 700 W for 10 min. Brazilian disc tests were conducted on sandstone samples after microwave radiation under both quasi-static and dynamic loading conditions. Test results revealed that, with the increase of the initial water content, the microwave heating capacity of the rock is significantly improved. The surface temperature of the saturated samples is approximately 1.38 times higher than that of the dry ones. Moreover, weight, P-wave velocity, quasi-static and dynamic tensile strength of the rock decrease, while porosity and damage factor exhibit a similar growth law. Before microwave irradiation, the average value of the P-wave velocity and the quasi-static tensile strength of sandstone were about 2521.3 m·s−1 and 4.65 MPa. However, after microwave treatment, when the initial water content was 2%, 3%, 4% and 5.4%, the P-wave velocity decreased by 6.1%, 9.8%, 16.4% and 30.2%, while that quasi-static tensile strength reduced by 9.2%, 16.7%, 30.6% and 48.9%, respectively. For water-saturated samples under microwave irradiation, the porosity increases from 13.02% to 18.12% (showing an increase of 39.2%), and the damage value rises to 0.51. In addition, the dynamic tensile strength shows a significant loading rate dependence, and as the initial water content increases, also the dynamic increase factor (DIF) increases. At a given loading rate, the energy dissipation decreases with the increase of the initial water content, which indicates that the presence of water cause more significant damage to the rock when subjected to microwave radiation. Scanning electron microscopy (SEM) results indicate that the internal damage of the rock after microwave radiation is dominated by intergranular cracks, and crack density increases with increasing initial water content of the samples. The underlying damage mechanisms of microwave radiation on water-bearing sandstone were interpreted with the theory of pore water pressure and structural thermal stresses.