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1.
An alloy containing 80.0 pct Ni, 12.65 pct Fe, 6.74 pct Mo, 0.36 pct Zr, and 0.25 pct Mn by weight was cast, homogenized,
and successively cold rolled into thin strips with area reductions of 0, 50, 75, and 90 pct. Annealed samples were studied
by optical and electron microscopy, electron diffraction, and magnetic testing to determine the effects of cold work and annealing
upon the microstructure and magnetic properties of the alloy. Cold work produced a high initial hardness together with high
coercive force. Recrystallization of the cold worked structures occurred upon annealing at 600°C (873 K) and above and caused
significant and parallel decreases in hardness and coercive force. The activation energy for recrystallization was found to
be 80.5 kcal/g mole (337.0 kJ/g mole) for the 50, 75, and 90 pct cold worked specimens. After annealing at 600°C (873 K),
a small number of spherical Ni4Mo particles were observed, but the particles produced little change in magnetic properties apparently because of their relatively
coarse size and large spacing. Beginning at 700°C (973 K) ribbon-shaped particles of a Ni5Zr intermetallic compound also precipitated out of solid solution. Both the Ni4Mo and Ni5Zr precipitates were the result of a homogeneous continuous precipitation reaction within the grains. A peak in coercive force
at 800°C (1073 K) is attributed to domain wall pinning associated with the fine distribution of rodlike Ni5Zr particles. Cold working 90 pct and aging at 800°C (1073 K) was found to increase coercive force by almost 60 pct from the
minimum produced by complete recrystallization. Annealing, however, decreased hysteresis and improved squareness. 相似文献
2.
U. Kamachi Mudali N. Bhuvaneswaran P. Shankar H. S. Khatak B. Raj 《Metallurgical and Materials Transactions A》2004,35(6):1799-1806
This article presents the preparation, characterization, and hot-salt oxidation behavior of nitrogen-containing type 316L
stainless steel (SS), surface modified with intermetallic coatings. Three different types of intermetallic coating systems,
containing aluminum, titanium, and titanium/aluminum multilayers, were formed by diffusion annealing of type 316L austenitic
SS containing 0.015, 0.1, 0.2, and 0.56 pct nitrogen. Analysis by using X-ray diffraction (XRD), scanning electron microscopy
(SEM), and secondary ion mass spectroscopy (SIMS) confirmed the formation of various intermetallic phases such as AIN, Al13Fe4, FeAl2, FeTi, Ti2N, and Ti3Al in the coatings. Hot salt oxidation behavior of the uncoated and surface-modified stainless steels was assessed by periodic
monitoring of the weight changes of NaCl salt-applied alloys kept in an air furnace at 1023 K up to 250 hours. The oxide scales
formed were examined by XRD and stereomicroscopy. Among the various surface modifications investigated in the present study,
the results indicate that the titanium-modified alloys show the best hot-salt oxidation resistance with the formation of an
adherent, protective, thin, and continuous oxide layer. Among the four N-containing alloys investigated, the titanium and
Ti/Al multilayer modified 0.56 pct N alloy showed the best hot-salt oxidation resistance as compared to uncoated alloys. The
slower corrosion kinetics and adherent scale morphology indicate that the surface-modified titanium intermetallic coatings
could provide high-temperature service applications up to 1073 K, particularly in chloride containing atmospheres, for austenitic
stainless steels. 相似文献
3.
Formation and Stability of Equiatomic and Nonequiatomic Nanocrystalline CuNiCoZnAlTi High-Entropy Alloys by Mechanical Alloying 总被引:1,自引:0,他引:1
Varalakshmi S. Kamaraj M. Murty B.S. 《Metallurgical and Materials Transactions A》2010,41(10):2703-2709
Nanocrystalline equiatomic high-entropy alloys (HEAs) have been synthesized by mechanical alloying in the Cu-Ni-Co-Zn-Al-Ti
system from the binary CuNi alloy to the hexanary CuNiCoZnAlTi alloy. An attempt also has been made to find the influence
of nonequiatomic compositions on the HEA formation by varying the Cu content up to 50 at. pct (Cu
x
NiCoZnAlTi; x = 0, 8.33, 33.33, 49.98 at. pct). The phase formation and stability of mechanically alloyed powder at an elevated temperature
(1073 K [800 °C] for 1 hour) were studied. The nanocrystalline equiatomic Cu-Ni-Co-Zn-Al-Ti alloys have a face-centered cubic
(fcc) structure up to quinary compositions and have a body-centered cubic (bcc) structure in a hexanary alloy. In nonequiatomic
alloys, bcc is the dominating phase in the alloys containing 0 and 8.33 at. pct of Cu, and the fcc phase was observed in alloys
with 33.33 and 49.98 at. pct of Cu. The Vicker’s bulk hardness and compressive strength of the equiatomic nanocrystalline
hexanary CuNiCoZnAlTi HEA after hot isostatic pressing is 8.79 GPa, and the compressive strength is 2.76 GPa. The hardness
of these HEAs is higher than most commercial hard facing alloys (e.g., Stellite, which is 4.94 GPa). 相似文献
4.
J. P. Neumann A. Mikula Y. A. Chang 《Metallurgical and Materials Transactions A》1982,13(7):1123-1126
The crystal structure and the precise lattice parameters of palladium-cadmium alloys containing 33 to 60 at. pct Cd were determined
by X-ray diffraction at 294 K, using samples quenched from 1073 K. The results indicate that at 1073 K the β1(Ll0) phase extends from 33 to 55 at. pct Cd while the β′(B2) phase is stable from 56 to 60 at. pct Cd. No evidence for the existence
of a separate high-temperature phase between the β, and β′ phase fields was found. A modification of the currently accepted
Pd-Cd phase diagram near the equiatomic composition is proposed. The lattice parameters of the fct β1 - phase have the following values at the stoichiometric composition:a = 0.4 2817 nm,c = 0.3 6310 nm. The molar volume of the β1-phase is a linear function of composition from 33 to 50 at. pct Cd. The partial molar volumes of Pd and Cd have the following
values in this range: VPd = 8.87 cm3/g-atom, VCd = 11.18 cm3/g-atom. An analysis of Pd-and Pt-based Ll0 phases indicates that the c/a ratio of these phases is related to their enthalpy of formation. Phases with a small enthalpy
of formation have a high c/a ratio while phases with a large enthalpy of formation exhibit a small c/a ratio.
Y. A. CHANG, formerly Professor of Materials Engineering and Associate Dean for Research, Graduate School, University of Wisconsin-Milwaukee 相似文献
5.
Yu-Kai Chen Chia-Ming Hsu Sinn-Wen Chen Chih-Ming Chen Yu-Chih Huang 《Metallurgical and Materials Transactions A》2012,43(10):3586-3595
Sn-Co-Cu ternary alloys are promising lead-free solders, and isothermal sections of Sn-Co-Cu phase equilibria are fundamentally important for the alloys?? development and applications. Sn-Co-Cu ternary alloys were prepared and equilibrated at 523?K, 1073?K, and 1273?K (250?°C, 800?°C, and 1000?°C), and the equilibrium phases were experimentally determined. In addition to the terminal solid solutions and binary intermetallic compounds, a new ternary compound, Sn3Co2Cu8, was found. The solubilities of Cu in the ??-CoSn3 and CoSn2 phases at 523?K (250?°C) are 4.2 and 1.6?at. pct, respectively, while the Cu solubility in the ??-Co3Sn2 phase is as high as 20.0?at. pct. The Cu solubility increases with temperature and is around 30.0?at. pct in the ??-Co3Sn2?at 1073?K (800?°C). The Co solubility in the ??-Cu6Sn5 phase is also significant and is 15.5?at. pct at 523?K (250?°C). 相似文献
6.
J. Breuer A. Grün F. Sommer E. J. Mittemeijer 《Metallurgical and Materials Transactions B》2001,32(5):913-918
The enthalpy of formation of the ordered B2 phases in the Fe-Al and Fe-Ni-Al systems was measured with very good accuracy
using a special, laboratory-built differential-solution calorimeter. The measurements were performed at 1073 K as a function
of composition, with an accuracy of about 1 pct. The enthalpy of formation of B2-FeAl is most negative for the composition
Fe0.50Al0.50 (−36.29 kJ/mol). Compounds with Al contents less than about 40 at. pct show a deviation from the linear dependence of the
enthalpy of formation with composition which prevails for Al contents larger than 40 at. pct. Upon replacing Fe by Ni while
maintaining a constant Al content, the enthalpy of formation of B2-(Fe,Ni)Al compounds becomes more negative. With decreasing
Al content and for a constant Fe/Ni ratio, the enthalpy of formation of the ternary phase becomes less negative. 相似文献
7.
T. Chen P. M. Green J. L. Jordan J. M. Hampikian N. N. Thadhani 《Metallurgical and Materials Transactions A》2002,33(6):1737-1742
The oxidation of Ti3SiC2 composites (75 at. pct Ti3SiC2 and 25 at. pct TiC
x
), prepared via self-propagating high-temperature synthesis (SHS) and subsequent shock consolidation, has been studied in the range of 1073
to 1573 K in this research. The oxidation kinetics are parabolic with an activation energy of approximately 240±20 kJ/mol.
As shown by transmission electron microscopy (TEM) during the very early stages of oxidation, the oxide layer formed contains
amorphous SiO2 and crystalline rutile (TiO2). As oxidation proceeds, a two-layered oxide scale is observed with the outer oxide layer consisting of columnar TiO2 with trace amounts of SiO2 and the inner oxide layer being comprised of a mixture of amorphous SiO2 and fine crystalline TiO2. The grain size of the outermost oxide (TiO2) increases with increasing oxidation temperature. The oxidation resistance of the Ti3SiC2 composites prepared by SHS and subsequent shock consolidation is similar to the oxidation of Ti3SiC2 prepared by other means with comparable parabolic constants. 相似文献
8.
Guillaume Reboul Shoichi Nambu Junya Inoue Toshihiko Koseki 《Metallurgical and Materials Transactions A》2012,43(7):2366-2377
Liquid-phase bonding experiments were performed at 1073?K (800?°C) between ZIRCALOY-2 and type 316 austenitic stainless steel by inserting zinc as an interlayer. The evolution of the microstructure at the interface was studied and the formation of various phases was detected. On the zirconium side, the very rapid formation of Zn3Zr was detected, whereas on the steel side, an unexpectedly large amount of the base austenitic steel was observed to react with liquid Zn. The reacted iron solidified into a nickel-poor ferritic phase containing around 10?mol?pct?zinc, which grew into the austenite accompanied by a formation of a zinc-rich phase containing nickel. The reaction stopped when the zinc-rich phase reached saturation with a nickel content between 20 and 25?mol?pct. Thermodynamic calculations showed that the addition of nickel to liquid zinc greatly decreases the free energy of the liquid phase, thus enabling a large stability range for the ferrite?+?liquid zone and reducing the stability range of the austenite. The primary equilibrium between the austenite and the liquid phase is thus metastable, and thus, the austenite transforms into ferrite and a high-nickel-content liquid. The transformation front then progresses until ternary equilibrium is reached between austenite, ferrite, and the zinc-rich phase. 相似文献
9.
Fe-V alloys containing 1.06 wt pct V, 5.23 wt pct V and 15.55 wt pct V, have been nitrided in purified NH3 gas in temperatures ranging between 773 K and 1173 K. The nitriding kinetics of all these alloys in this temperature range
obey a parabolic rate law. The comparison of the nitriding rate constants evaluated from experimental results and from the
calculations based on Wagner's internal oxidation model show a deviation which is explained in terms of the effect of the
lattice strains on the solubility and diffusivity of nitrogen in the Fe matrix. The hardness of the nitrided zone increases
with the vanadium content in solution and reaches a saturation value of about 1300 VHN (12.75 GNm−2) which corresponds to about 4 wt pct V. The hardening in the nitrided region is cuased by the precipitation of VN which cannot
be observed on specimens nitrided at the lower limits of the temperature range. Precipitates grown in size can be seen on
specimens nitrided at 1073 K and 1173 K. 相似文献
10.
S. Majumdar D. Schliephake B. Gorr H.-J. Christ M. Heilmaier 《Metallurgical and Materials Transactions A》2013,44(5):2243-2257
The oxidation behavior of 0.2 Y-alloyed Mo-9Si-8B (at. pct) was investigated in a wide temperature range from 923 K to 1673 K (650 °C to 1400 °C). Formation of a thin yttrium-silicate scale at the outer layer along with the thick silica-rich inner layer containing Y-rich oxide inclusions was detected beyond 1573 K (1300 °C). A substantial improvement in the oxidation resistance of the alloy could be realized at 1073 K to 1273 K (800 °C to 1000 °C) with the addition of yttrium. The formation of a viscous silica-rich protective scale could prevent the permeation of MoO3 at the initial stages of oxidation at this temperature regime. The growth of the internal oxidation zone followed a parabolic rate at 1273 K to 1673 K (1000 °C to 1400 °C), and the activation energy values calculated for both the outer oxide scale and internal oxidation zone formation indicated the inward diffusion of oxygen as the dominant rate controlling mechanism. The microstructural and kinetic data obtained for internal and external oxidation indicate that yttrium-silicate scale reduces the inward diffusion of oxygen, thereby improving the oxidation resistance of the alloy at high temperatures in any oxidizing environment. 相似文献
11.
D. K. Mukhopadhyay C. Suryanarayana F. H. FROES 《Metallurgical and Materials Transactions A》1995,26(8):1939-1946
The structural evolution in mechanically alloyed binary aluminum-iron powder mixtures containing 1, 4, 7.3, 10.7, and 25 at.
pct Fe was investigated using X-ray diffraction (XRD) and electron microscopic techniques. The constitution (number and identity
of phases present), microstructure (crystal size, particle size), and transformation behavior of the powders on annealing
were studied. The solid solubility of Fe in Al has been extended up to at least 4.5 at. pct, which is close to that observed
using rapid solidification (RS) (4.4 at. pct), compared with the equilibrium value of 0.025 at. pct Fe at room temperature.
Nanometer-sized grains were observed in as-milled crystalline powders in all compositions. Increasing the ball-to-powder weight
ratio (BPR) resulted in a faster rate of decrease of crystal size. A fully amorphous phase was obtained in the Al-25 at. pct
Fe composition, and a mixed amorphous phase plus solid solution of Fe in Al was developed in the Al-10.7 at. pct Fe alloy,
agreeing well with the predictions made using the semiempirical Miedema model. Heat treatment of the mechanically alloyed
powders containing the supersaturated solid solution or the amorphous phase resulted in the formation of the Al3Fe intermetallic in all but the Al-25 at. pct Fe powders. In the Al-25 at. pct Fe powder, formation of nanocrystalline Al5Fe2 was observed directly by milling. Electron microscope studies of the shock-consolidated mechanically alloyed Al-10.7 and
25 at. pct Fe powders indicated that nanometer-sized grains were retained after compaction. 相似文献
12.
13.
The formation of zinc ferrite (ZnFe2O4) during the fluidized-bed roasting of zinc concentrates presents subsequent processing difficulties both for zinc recovery
and for iron separation and disposal. A major source of iron in these concentrates is from the iron sulfides — pyrite and
pyrrhotite. This study examined the changes undergone by these iron minerals when roasted together with sphalerite at 1223
K in a fluidizing gas mixture of 3 pct oxygen and 97 pct nitrogen. Optical microscopy and electron microprobe analysis were
employed to identify the three stages that lead to ferrite formation and to examine the processes that occur within each stage.
The first stage is oxidation of the sulfides to highly vesicular, amorphous magnetite particles containing small amounts of
zinc. The second stage involves both densification of these particles by sintering and counterdiffusion of iron and zinc cations
to form a continuous phase of homogeneous zinc-rich spinel and a precipitate of hematite. In the third stage, continuation
of cation diffusion and increasingPo
2 results in the formation of stoichiometric zinc ferrite. These observations have been interpreted by reference to the established
phase relationships that occur in the Zn-Fe-O system, and a detailed, solid state reaction mechanism for the formation of
zinc ferrite has been proposed. 相似文献
14.
The formation of zinc ferrite (ZnFe2O4) during the fluidized-bed roasting of zinc concentrates presents subsequent processing difficulties both for zinc recovery and for iron separation and disposal. A major source of iron in these concentrates is from the iron sulfides — pyrite and pyrrhotite. This study examined the changes undergone by these iron minerals when roasted together with sphalerite at 1223 K in a fluidizing gas mixture of 3 pct oxygen and 97 pct nitrogen. Optical microscopy and electron microprobe analysis were employed to identify the three stages that lead to ferrite formation and to examine the processes that occur within each stage. The first stage is oxidation of the sulfides to highly vesicular, amorphous magnetite particles containing small amounts of zinc. The second stage involves both densification of these particles by sintering and counterdiffusion of iron and zinc cations to form a continuous phase of homogeneous zinc-rich spinel and a precipitate of hematite. In the third stage, continuation of cation diffusion and increasingPo 2 results in the formation of stoichiometric zinc ferrite. These observations have been interpreted by reference to the established phase relationships that occur in the Zn-Fe-O system, and a detailed, solid state reaction mechanism for the formation of zinc ferrite has been proposed. 相似文献
15.
Pascal Coursol Arthur D. Pelton Manuel Zamalloa 《Metallurgical and Materials Transactions B》2003,34(5):631-638
The liquidus surfaces of the Cu2O-CaO, Cu2O-Na2O, and Cu2O-CaO-Na2O phase diagrams in equilibrium with metallic Cu were measured by thermal analysis at compositions varying from approximately
0 to 35 wt pct Na2O and 0 to 15 wt pct CaO. Solubilities in the solid binary terminal solutions were also measured by wavelength dispersive
X-ray spectrometer analysis. Copper oxide activities in binary liquid slags were determined from the measured oxygen content
of the metallic copper equilibrated with the slags. The ternary system is a simple eutectic system. No ternary compounds were
observed. The Cu2O-CaO binary eutectic was measured at 1140 °C±10 °C at 10±1 wt pct CaO and the Cu2O-Na2O binary eutectic was measured at 803 °C±15 °C at 28±2 wt pct Na2O. The liquid slag was thermodynamically modeled with the modified quasi-chemical model, while the solid Cu2O-rich solution was treated as Henrian ideal. All data from the present work and from the literature (phase diagrams and activities)
for the binary systems were evaluated simultaneously by least-squares optimization in order to obtain the best model parameters.
With only these binary parameters, the calculated ternary liquidus surface is in very good agreement with the measurements.
Finally, using the model, the liquidus projection of the Cu2O-CaO-Na2O system in equilibrium with Cu was calculated as well as the oxygen content of the equilibrated Cu as a function of slag
composition. 相似文献
16.
The ball milling of elemental powders corresponding to Γ (Fe3Zn10)+0.12 wt pct Si; Γ1 (Fe5Zn21) + 0.12 wt pct Si; δ (FeZn7)+0.12 wt pct Si; and ζ (FeZn13)+0.12 wt pct Si composition ratios yields crystalline, mechanically alloyed phases. Differential scanning calorimetry (DSC)
measurements of these materials show that they evolve differently, with well-defined characteristic stages. The activation
energies for processes corresponding to these stages, based on kinetic analyses, are determined and correlated to microstructural
evolvements. The processes occurring during the first stage below 250 °C, for all of the materials studied using X-ray diffraction
(XRD) analysis, are associated with release of strain, recovery, and limited atomic diffusion. The activation energies for
recovery processes are 120 kJ/mole for the Γ+0.12 wt pct Si, 131 kJ/mole for δ+0.12 wt pct Si, and 96 kJ/mole for ζ+0.12 wt pct Si alloys. At higher temperatures, recrystallization and other structural transformations occur with activation
energies of 130 and 278 kJ/mole for Γ+0.12 wt % Si; of 161 kJ/mole for Γ1+0.12 wt pct Si; of 167 and 244 kJ/mole for δ+0.12 wt pct Si; and of 641 kJ/mole for the ζ+0.12 wt pct Si. In addition, a eutectic reaction at 420 °C±3 °C, corresponding to the Zn-Si system, and a melting of Zn in
Fe-Zn systems are observed for the ζ+0.12 wt pct Si material. The relation of FeSi formation in the Sandelin process is discussed. 相似文献
17.
High-temperature thermodynamic properties of Pt−Zr alloys containing 2 to 25 at. pct Zr and Pt−Hf alloys containing 20 to
25 at. pct Hf have been measured over the temperature range 1100 to 1400 K by a galvanic cell technique using a thoria-based
electrolyte. Activities of Zr and Hf show large negative deviations from Raoult's Law; at 1300 K and 23 at. pct Zr of Hf,
for instance,a
Zr=6.5×10−16 anda
Hf=7.9×10−17. Correlation of emf results with X-ray phase data enables calculation of standard free energies of formation of the intermetallic
compounds ZrPt5, ZrPt3, and HfPt3. At 1300 K ΔG
f
0
(ZrPt5) =−92,680 cal/mole; ΔG
f
0
(ZrPt3)=−91,740 cal/mole; and ΔG
f
0
(HfPt3)=−97,350 cal/mole. The high stabilities of phases in the Pt−Ti, Pt−Zr, and Pt−Hf systems verify the predictions of the Engel-Brewer
correlation. The large negative entropies of formation of TiPt3, ZrPt3 are discussed. Applications including side reactions in fuel cells and thermocouple systems are mentioned.
P. J. MESCHTER, formerly a Graduate Student at the University of Pennsylvania
This paper is based upon a dissertation submitted by P. J. Meschter in partial fulfillment of the requirements of the degree
of Doctor of Philosophy at the University of Pennsylvania. 相似文献
18.
The heat of formation of the metastable phase y(Au-Sn) with the D81-3 (γ-brass) structure containing 20.5 at. pct Sn was measured by tin solution calorimetry as △Hγ = —0.94 ±0.16 kcal/g-atom.
Its free energy of formation was estimated and suggests that y at low temperatures comes close to being an equilibrium phase.
The undercooling required for the formation of y was also estimated. This undercooling is prohibitively high (285 to 440 K)
for an alloy containing 20.5 at. pct Sn, but is moderate (70 to 160 K) for an alloy containing 29.0 at. pct Sn. This difference
explains why y forms only in splat-cooled melts with an excess of =>7.5 at. pct Sn above the composition of the γ phase. 相似文献
19.
E. W. Dewing 《Metallurgical and Materials Transactions B》1978,9(4):687-690
Electrical resistivity measurements have been used to demonstrate the existence of solid solutions of AlF3 in the high-temperature form of cryolite above the transition at 565°C. An expression was derived for the resistivity of single-phase mixtures as a function of composition and temperature, and it was then used to deduce the composition at the solid-solid phase boundaries. At the NaF-cryolite eutectic temperature (880°C) the boundary lies at 74.8 mole pct NaF, and at the chiolite peritectic temperature (737°C) the other boundary lies at 74.4 mole pct NaF. The variation of composition with activity of NaF is reasonably consistent with the hypothesis that solid solution leads to formation of AlF 4 1 ions and cation vacancies. On this basis extrapolation is made for the solid-liquid boundaries, and the solid solution region is found to touch the liquidus at 74.0 mole pct NaF. On the above hypothesis the anomalous heat content of cryolite between 888°C and the melting point can be accounted for. 相似文献
20.
B. Vishwanadh R. H. Naina S. Majumdar R. Tewari G. K. Dey 《Metallurgical and Materials Transactions A》2013,44(5):2258-2269
In the current work, silicide coatings were produced on the Nb alloy (Nb-1 pct Zr-0.1 pct C) using the halide activated pack cementation (HAPC) technique. Coating parameters (temperature and time) were optimized to produce a two-layer (Nb5Si3 and NbSi2) coating on the Nb alloy. Subsequently, the oxidation behavior of the Nb alloy (Nb-1 pct Zr-0.1 pct C) and silicide-coated Nb alloy was studied using thermogravimetric analysis (TGA) and isothermal weight gain oxidation experiments. Phase identification and morphological examinations were carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. TGA showed that the Nb alloy started undergoing accelerated oxidation at and above 773 K (500 °C). Isothermal weight gain experiments carried out on the Nb alloy under air environment at 873 K (600 °C) up to a time period of 16 hours exhibited a linear growth rate law of oxidation. In the case of silicide-based coatings, TGA showed that oxidation resistance of silicide coatings was retained up to 1473 K (1200 °C). Isothermal weight gain experiments on the silicide coatings carried out at 1273 K (1000 °C) in air showed that initially up to 8 hours, the weight of the sample increased, and beyond 8 hours the weight of the sample remained constant. The oxide phases formed on the bare samples and on the coated samples during oxidation were found to be Nb2O5 and a mixture of SiO2 and Nb2O5 phases, respectively. SEM showed the formation of nonprotective oxide layer on the bare Nb alloy and a protective (adherent, nonporous) oxide layer on silicide-coated samples. The formation of protective SiO2 layer on the silicide-coated samples greatly improved the oxidation resistance at higher temperatures. 相似文献