Aero-engine turbine stator blades are often used in harsh environments with high temperatures and high pressure and are prone to fatigue fractures. Real-time and accurate monitoring of blade surface ...stress and strain is critical to ensure safe operation. In this study, thin-film strain gauges (TFSGs) that can be used in high-temperature environments above 1000 °C were designed and fabricated using a PtRh6 thin film as the sensitive material. The hysteresis effect of the stress transfer upon establishing a thermo-mechanical coupling finite element model of the Inconel718 high-temperature nickel-based alloy equal-strength beam PtRh6 TFSGs was analyzed and the optimal combination of thin-film thickness and longitudinal grid length of wire-grid TFSGs was determined. In order to solve the problem of high-temperature insulation, the insulating properties of a single-layer Al2O3 insulating film, a single-layer ZrO2 insulating film, a double-layer Al2O3/ZrO2 composite insulating film, and a four-layer Al2O3/ZrO2/Al2O3/ZrO2 composite insulating film at high temperature were compared and studied using scanning electron microscopy to analyze the microscopic morphology and composition of the four insulating film structures. The results showed that the four-layer Al2O3/ZrO2/Al2O3/ZrO2 composite insulating film had the best insulating properties at high temperatures. On this basis, an Al2O3/ZrO2/Al2O3/ZrO2 composite insulating film, PtRh6 sensitive layer, and Al2O3 protective film were sequentially deposited on a high-temperature nickel-based alloy equal-strength beam using DC pulsed magnetron sputtering technology to obtain an Inconel718 high-temperature nickel-based alloy equal-strength beam PtRh6 TFSG. Its gauge factor (GF) and temperature coefficient of resistance (TCR) were calibrated, and the results showed that the sensor could be used in harsh environments of 1000 °C. The above results provide new ideas for measuring stress and strain in aerospace under high-temperature and high-pressure environments.
During the titanium alloy milling process, high temperatures in the tool-chip contact area will affect the tool life and precision of titanium alloy machining. Therefore, it is essential to measure ...the temperature of the tool-chip contact area continuously. In this paper, a finite element simulation model of the milling process was established using ABAQUS2020 to obtain the highest temperature location in the tool-chip contact area when milling titanium alloy. The integration of the wire with the alumina ceramic substrate formed an integrated wire substrate. Furthermore, NiCr, NiSi, and SiO2 films were deposited on the substrate sequentially using the DC pulsed magnetron sputtering technique. Finally, its microscopic morphology and static and dynamic performance were tested. The results show that the developed thin-film thermocouple temperature sensor has a Seebeck coefficient of 40.72 μV/°C and a dynamic response time of 0.703 ms. The application of the sensor to our titanium alloy milling experiments showed that the sensor can monitor the transient temperature in the tool-chip contact area, and its temperature measurement performance showed no detrimental effect from wearing. The effect of each milling parameter on the milling temperature was analyzed using ANOVA, and a regression model with an R-sq of 96.76% was obtained for the milling temperature.
The absence of suitable composition unit model hampered the exploration of composition origin of garnet-type solid inorganic electrolytes (G-SIE), which further hindered the development all ...solid-state lithium ion (Li
+
) cells. In this report, the cluster-plus-glue-atom (CPGA) model was used to explore the chemical composition origin of G-SIE, as well as the relation between weak binding Li
+
and Li
+
vacancy/interstitials in G-SIE. Taking typical garnet structure Ca
3
Al
2
Si
3
O
12
as the original target, CPGA cluster formula Cluster
Ca/Al
is established as Al-O
6
(Si/Ca)
3
. Then, CPGA unit cluster of garnet structure is established as (Cluster)-(Cluster)
14
(Cluster). By introducing Li
+
, La
3+
, and Nb
5+
cations, the garnet structure Li
5
La
3
Nb
2
O
12
is obtained, which consists of Cluster
La/Nb
with Nb-O
6
(Li/La)
3
Li structure. Here, the weak binding Li
+
has been introduced into the garnet-type Li
5
La
3
Nb
2
O
12
, successfully. However, because of lacking Li
+
vacancy/interstitials, the ionic conductivity of Li
5
La
3
Nb
2
O
12
is unsatisfactory. By replacing Nb
5+
with Zr
4+
, the garnet structure Li
7
La
3
Zr
2
O
12
is obtained, which consists of Cluster
La/Zr
in Zr-O
6
(Li/La)
3
Li
2
structure. Because of containing both weak binding Li
+
and Li
+
vacancy/interstitials, the ionic conductivity of Li
7
La
3
Zr
2
O
12
is improved obviously. Now, the composition origin of G-SIE has been explored by CPGA model. In future, based on CPGA cluster formula and unit cluster of garnet structure, the ionic conductivity of G-SIE based on Li
7
La
3
Zr
2
O
12
could be further improved by the replacement of Zr
4+
with trivalent cations and/or variable valence cations, the reduction of SIE film thickness, as well as the improvement of Li
+
transport route.
Pure and Sn/Fe co-doped (0.2 at.% Sn and 0.6 at.% Fe, 0.6 at.% Sn and 0.2 at.% Fe, 1.0 at.% Sn and 1.0 at.% Fe) TiO2 nanoparticles were synthesized via a sol-gel method and subsequently calcined at ...different temperatures. Furthermore, the particles were analyzed by TG-DSC, XRD, TEM, HRTEM, EDS, SAED and UV–Vis for investigating the influences of dopant and calcination temperature on the thermal effect, composition, morphology, energy band gap (Eg) and the degradation efficiency of methyl orange (MO) under various light irradiations respectively. Results indicated that Sn/Fe co-doping inhibited the crystallization transformation from anatase to rutile phase of TiO2 and decreased the Eg. The increased calcination temperature and Sn/Fe co-doped effect brought about the abnormal grain growth of TiO2 nanoparticles. 0.6 at.% Sn/0.2 at.% Fe and 1.0 at.% Sn/1.0 at.% Fe co-doped TiO2 nanoparticles presented better photocatalytic performance than pure and 0.2 at.% Sn/0.6 at.% Fe co-doped TiO2 nanoparticles under visible light irradiation mainly due to the decreased Eg. On the contrary, 0.2 at.% Sn and 0.6 at.% Fe co-doped TiO2 nanoparticles calcined at 650 °C showed the most excellent photocatalytic performance under UV light irradiation, which was about twice as large as that of pure TiO2 possibly due to the formed hybrid structure of anatase and rutile phase as well as the h+-mediated decomposition pathway.
Metal atoms were deposited on an Si (111)-7 × 7 surface, and they were adsorbed with alcohol gases (CH3OH/C2H5OH/C3H7OH). Initially, CnH2n+1OH adsorption was simply used as an intermediate layer to ...prevent the chemical reaction between metal and Si atoms. Through scanning tunneling microscopy (STM) and a mass spectrometer, the CnH2n+1OH dissociation process is further derived as the construction of a surface quasi-potential with horizontal and vertical directions. With the help of three typical metal depositions, the surface characteristics of CH3OH adsorption are more clearly presented in this paper. Adjusting the preheating temperature, the difference of thermal stability between CH3O– and H+ could be obviously derived in Au deposition. After a large amount of H+ was separated, the isolation characteristic of CH3O– was discussed in the case of Fe deposition. In the process of building a new metal-CH3O–-H+ model, the dual characteristics of CH3OH were synthetically verified in Sn deposition. CH3O– adsorption is prone to influencing the interaction between the metal deposition and substrate surface in the vertical direction, while H+ adsorption determines the horizontal behavior of metal atoms. These investigations lead one to believe that, to a certain extent, the formation of regular metal atomic structures on the Si (111)-7 × 7-CH3OH surface is promoted, especially according to the dual characteristics and adsorption models we explored.
Previous studies on the preparation of ZnSnO
3
under normal pressure and non-epitaxy conditions are ambiguous and contradictory. Therefore, the phase evolution in preparing ZnSnO
3
powder with ...different calcination temperatures was systematically studied by precipitation method under normal pressure in the present work. The phase of the samples was characterized by XRD and Raman spectroscopy. Due to lacking the reliable Raman data of ZnSnO
3
in previous literatures, the Raman spectra of ZnSnO
3
with LiNbO
3
-type structure and ilmenite-type structure were simulated by first principle based on CASTEP module of Materials Studio. Moreover, the TG-DSC analysis was carried out for the as-dried precursor powder to further clarify the phase evolution. The results indicated that the phase of the as-dried precursor powder was ZnSn(OH)
6
with cubic structure and a series of decomposition reactions occurred with increasing calcination temperature. Wherein, ZnSn(OH)
6
began to decompose into ZnSnO
3
at about 170 °C, and then ZnSnO
3
began to decompose into Zn
2
SnO
4
and SnO
2
at about 320 °C. Namely, the thermal stability temperature of ZnSnO
3
should be lower than 320 °C under normal pressure. Furthermore, the beginning crystallization temperature for the decomposition-achieved Zn
2
SnO
4
and SnO
2
was about 670 °C. In addition, the morphologies of all the samples were detected by SEM, and mainly determined by the crystal structures of the phases in the samples.
Aluminum zinc oxide (AZO) nanoparticles were successfully synthesized by a facile and environment friendly ethanol-assisted coprecipitation method. The other two coprecipitation methods were studied ...to obtain AZO nanoparticles using the same granular Zn but different processes (i) homogeneous coprecipitation and (ii) seed-induced coprecipitation simultaneously for comparison. The AZO precursor prepared by ethanol-assisted coprecipitation displayed the unique endothermic heat behavior which was different from the other two counterparts, leading to the hexagonal ZnO structure with (002) crystallized preferred orientation and flat-elongated-granulated complex morphology after calcination at 600 °C, exhibiting outstandingly higher sinter activity than other two counterparts, and achieving a nearly full relative density (99.1%) of AZO ceramic at only 1200 °C through the traditional pressureless sintering technique. The mechanism of crystallized preferred orientation of AZO nanoparticles and sintering densification of AZO ceramics were lastly proposed.
SnO
2
nanoparticles were successfully synthesized by a novel one-pot route using two various Sn salts of SnCl
4
·5H
2
O and SnCl
2
·2H
2
O as raw materials, respectively. The ...thermogravimetric-differential scanning calorimeter (TG-DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and gas sensitivity measurement were characterized to determine the influences of salt type and calcination temperature on the thermal effect, crystal structure, crystallite size and gas sensitivity of SnO
2
nanoparticles. Results indicated that the two series of samples had different crystallization process, crystallite size and gas sensitivity changed with calcination temperature. SnCl
4
·5H
2
O helped to promote crystallization, but SnCl
2
·2H
2
O suppressed the crystallization and crystallite growth even at the same calcination temperature. SnO
2
nanoparticles calcined at 500 °C using SnCl
4
·5H
2
O and 250 °C using SnCl
2
·2H
2
O displayed better gas sensitivity because of high crystallinity and small crystallite size, possibly decreasing the number of boundary defects which can cause electron recombination as well as providing more reaction cites, respectively.
N, Fe single doped and co-doped anatase TiO
2
nanoparticles were successfully prepared by coprecipitation method using TiCl
4
, NH
4
OH, Fe(NO
3
)
3
·9H
2
O as raw materials and polyvinyl alcohol as ...dispersant. The samples were characterized by TG-DSC, FTIR, XRD, FESEM, EDS, XPS, and UV–Vis to investigate the influence of doping concentration on the thermal effect, crystal structure, morphology, composition, energy band gap and photocatalytic activity of TiO
2
nanoparticles. Results indicated that TiO
2
nanoparticles doped with 0.15 at.% N and 0.3 at.% Fe showed the best photocatalytic activity. N, Fe co-doping had a synergistic effect: (1) The transformation inhibition of anatase to rutile phase was achieved, leading to formation of high crystallized monophasic anatase TiO
2
; (2) The bandgap narrowing effect was significant, increasing the light absorption range; (3) The small grain size of ~ 10 nm in diameter was obtained, resulting in effective separation of photo-induced electrons and holes.
Display omitted
•For face and body centered cubic metal element A, clusters based on cluster-plus-glue-atom model are ACentral-A12NearestneighborA3Glue and ACentral-A14NearestneighborAGlue.•For face ...centered cubic solid solution alloys, unit cluster with cluster-plus-glue-atom model is ClusterCentral-ClusterNearestneighbor14ClusterGlue.•For body centered cubic solid solution alloys, unit cluster with cluster-plus-glue-atom model is ClusterCentral-ClusterNearestneighbor12ClusterGlue3.•The composition origin of all solid solution alloys used in thermocouple are analyzed by unit cluster with cluster-plus-glue-atom model.
The chemical composition proportion of solid solution alloys in thermocouples (TCs) field is preliminarily explored by the cluster-plus-glue-atom (CPGA) model. CPGA clusters for face-centered cubic (fcc) and body-centered cubic (bcc) structure elemental metal are established, which are the cubic octahedron and rhombic dodecahedron respectively. With introducing the solute A element into solvent B matrix, the solute A atoms will prefer to the certain sites of solvent B atoms in CPGA cluster. Setting a CPGA cluster consisted of solute A and solvent B atoms as the central cluster, Friedel oscillation perturbation of central cluster on surrounding CPGA clusters will be totally shielded along radial at the position of 3 times of size of central cluster. Then, CPGA unit clusters for fcc and bcc structure solid solution alloys are established, which consist of the central, nearest neighbor, and glue clusters. Take K type TCs as an example. The nominal and theoretical stable composition proportion for Ni-Cr/Ni-Si solid solution alloys are Ni90Cr10/Ni97Si3 (wt. %) and Ni96.9Si3.1/Ni89.5Cr10.5 (wt. %), which correspond well with each other. Finally, CPGA unit clusters for most solid solution alloys in TCs field are analyzed, which display the better correspondence to the nominal composition proportion of them.
PDF
