High-temperature Infiltration Research Articles

High temperature infiltration behavior and reaction characteristics of Colima volcanic ashes on gadolinium zirconate coatings deposited by atmospheric plasma spraying

AbstractVolcanic ashes are considered a serious threat to the aircraft industry. At high temperatures, they inflict severe thermochemical damage to the typical 7 wt.% yttria-stabilized zirconia thermal barrier coatings that protect the aircraft turbine. There is a need to evaluate alternative materials with excellent resistance to infiltration of molten siliceous particles, such as gadolinium zirconate. In this work, free-standing thermal barrier coatings of gadolinium zirconate were manufactured by atmospheric plasma spraying, varying deposit parameters to obtain different relative densities to evaluate the infiltration of molten Colima volcanic ashes for 1 h and 10 h at 1250 °C. The infiltration depth and the reaction products resulting from each interaction, were studied by different characterization techniques. In general, the coatings show high resistance to the infiltration of the volcanic ashes, reaching infiltration depths between 50 µm and 80 µm after 10 h of infiltration time. In this sense, gadolinium zirconate coatings are excellent candidates against the infiltration of Colima volcanic ashes compared to the typical yttria-stabilized zirconia-based thermal barrier coatings.

Amorphous interlayer assisted ductility of Mo-Cu alloy

Generally, binary immiscible alloys have poor plasticity due to weak interfacial bonding. In this study, an amorphous interlayer was introduced between Mo and Cu phases in Mo-Cu alloys by using the high-temperature infiltration method. With the increase of infiltrated temperature from 1300 °C to 1450 °C, the thickness of the amorphous interlayer wad increased from 2 nm to 13 nm. The formation process, thermodynamic driving force, stability of the amorphous interlayer in Mo-Cu alloy, and its contribution to mechanical properties were systematically investigated. By using the “macroscopic atom approach” Miedema's model, the thermodynamic driving force and stability of the amorphous interlayer were proved. It was found that the thickening of the amorphous interlayer can significantly improve the interfacial bonding, thus leading to an increase in the tensile strength of the Mo-Cu alloy from 520 to 600 MPa and failure strain from 0.15 to 0.31 The deformation behavior of the Mo-Cu alloy shows that the amorphous interlayer can effectively absorb interfacial dislocations during deformation, and relieve the stress concentration at the interface by crystallization, thus delaying the initiation and propagation of cracks at phase boundaries, which broke through the limitation of the trade-off between strength and plasticity of such Mo-Cu immiscible materials.

The effect of pre-sintering and high-temperature infiltration on the properties of single-domain YBCO bulk superconductors by the Y + 011 top-seeded infiltration growth process

The top-seeded infiltration growth process (TSIG) is one of the most important methods for the fabrication of single-domain rare-earth barium copper oxide (REBCO) bulk superconductors. The performance of samples is in the main closely related to the quality of the solid phase pellets (SPPs). In this paper, we report a new method for optimizing the SPPs and properties of single-domain REBCO bulks, including sintering of the SPPs (Y2O3 + BaCuO2), infiltration of the Ba–Cu–O liquid phase and the melting growth process. A group of single-domain YBCO bulk superconductors with a diameter of 20 mm have been fabricated by the modified RE + 011 TSIG method. Both the levitation force and the trapped field of the samples increase at first and then decrease with increase in the sintering time. The largest levitation force of 42.8 N and trapped field of 0.41 T (77 K, 0.5 T) are obtained in the sample sintered at 1000 °C for 4.5 h; this is mainly related to the optimal microstructure of the pre-sintered SPPs and the YBCO bulk. These results indicate that pre-sintering and high-temperature infiltration is a very important method for controlling the microstructure and improving the physical properties of single-domain YBCO bulk superconductors.

The Effect of Pre-Sintering and High Temperature Infiltration on the Properties of Single Domain Ybco Bulk Superconductors by Y + 011 Tsig Process

The Effect of Pre-Sintering and High Temperature Infiltration on the Properties of Single Domain Ybco Bulk Superconductors by Y + 011 Tsig Process

Friction and Wear Characteristics of Microporous Interface Filled with Mixed Lubricants of M50 Steel at Different Loads.

Improving the tribological performance of M50 steel under the conditions of wide load range is of great significance. In this study, the interfacial structure of surface micropores filled with Sn–Ag–Cu or Sn–Ag–Cu/whisker carbon nanotubes (whiskerCNT) of M50 material was prepared by laser additive manufacturing and high-temperature infiltration. From 2 to 22 N, the lubrication characteristics of Sn–Ag–Cu and whiskerCNT in surface micropores of M50 was investigated. Results indicate that Sn–Ag–Cu can precipitate to the worn surface and form a lubricating layer, which has a good lubricating effect. Moreover, the flow behavior of Sn–Ag–Cu on a worn surface can play the role of crack healing. At higher load, the strength of the lubricating film is enhanced by whiskerCNT, which renders the lubricating film not vulnerable to premature rupture.

Analysis of friction interfaces with sinusoidal microchannels and the hybrid lubrication mechanisms of a tribo-film

The tribological behavior of Ti-alloys is crucial for increasing the service life and improving their usage accuracy of aero/avia-components. In this study, the friction interfaces covered with sinusoidal microchannels filled with SnAgCu, graphene, and Al2O3 were successfully prepared using high-temperature infiltration and laser additive manufacturing. The tribological behaviors, which were measured using the MFT-5000 tribometer of a Ti-(SnAgCu-Al2O3-Graphene), were better than those of the Ti-alloy, Ti-SnAgCu, Ti-(SnAgCu-Al2O3), and Ti-(SnAgCu-Graphene). The low-hardness tribo-film acted as a new-style friction interface during wear and yielded good lubrication. Excellent lubrication of a tribo-film was mainly essential for SnAgCu plastic deformation, inter-lamellar separation of multilayer graphene, and rolling-sliding mixture of spherical Al2O3. This was also attributed to the coordinating functions of SnAgCu-Al2O3, SnAgCu-Graphene, and SnAgCu-Al2O3-Graphene.

Investigation of the preparation and tribological behavior of a frictional interface covered with sinusoidal microchannels containing SnAgCu and Ti3SiC2

Tribological behavior of 37NbCrCo steel is a key factor with regard to the service life of the gearing systems. We prepared the frictional interfaces covered with sinusoidal microchannels in 37NbCrCo material, using laser additive manufacturing. Subsequently, lubricants of SnAgCu and Ti3SiC2 were filled into the microchannels using high-temperature infiltration. On a MFT-5000 tribometer, tribological behaviors of 37NbCrCo–SnAgCu–Ti3SiC2 were superior to 37NbCrCo and 37NbCrCo–SnAgCu. Moreover, the Ti3SiC2 was wrapped into the SnAgCu alloys to ensure the formation of soft tribo-film on the high-hardness supporting layer. The following factors were responsible for the excellent friction and wear behaviors, namely: the Ti3SiC2-induced the formation of the tribo-film, plastic deformation of SnAgCu, the rolling friction of Ti3SiC2, and their cooperation functions.

High temperature interaction of volcanic ashes with 7YSZ TBC's produced by APS: Infiltration behavior and phase stability

High-temperature infiltration behavior and phase stability of yttria-stabilized zirconia (7YSZ) thermal barrier coatings (TBC) produced by atmospheric plasma spray interacting with volcanic ashes (VAs) are presented here. Three VAs from the Colima, Popocatepetl, and Eyjafjallajökull volcanoes have been used in this work. Previous to infiltration experiments, physicochemical characterization of the VAs was carried out including thermal analyses by DSC, structural studies by XRD, and ICP chemical composition measurements. TBCs' infiltration tests were carried out at 1250 °C for different times. Results showed that infiltration depth as a function of time behaves in a non-linear way. Mainly two important infiltration behaviors were identified corresponding to high- and slow-speed infiltration regimes. Higher infiltration kinetics was detected for VAs with lower SiO2 content. The extent of chemical degradation of the 7YSZ is directly related to the silica content. For greater SiO2 values, a higher content of monoclinic ZrO2 was observed leading to maximum values at intermediate annealing times between 2 and 5 h. This behavior can be correlated with the high-speed tetragonal to monoclinic ZrO2 transformation at short times (between 2 and 5 h) until a maximum monoclinic content is reached. After that, the reaction follows by the interplay of ZrSiO4 formation at the expense of previously formed m-ZrO2 together with the incorporation of Y and Zr to the glass melt.

Episodic heating of continental lower crust during extension: A thermal modeling investigation of the Ivrea-Verbano Zone

Rheology of the continental lower crust plays an integral role in governing the style of continental extension. Temperature-dependent creep deformation in the lower crust decreases lithospheric strength and promotes coupling of deformation in the brittle crust and upper mantle; however, few constraints exist concerning the thermal evolution of extending lower crust. Here, we present a high-temperature thermochronological investigation of the Ivrea-Verbano Zone—archetypal continental lower crust that was attenuated during opening of the Alpine Tethys oceanic basin. Rutile U–Pb dates collected from three samples spanning the bottom ∼2-km of the crustal section are between ∼160 and ∼180 Ma, and exhibit near-rim zonations in Zr, Hf, Nb and Ta. Thermal-kinematic modeling of these data, combined with existing rutile U–Pb dates, show that the base of the Ivrea-Verbano Zone experienced heating on two timescales: conductive heating over ∼10 Myr, associated with thinning of the lithospheric mantle, and advective heating over <0.1 Myr, associated with high-temperature infiltration of fluids during crustal exhumation. These constraints match the thermal predictions of geodynamic models that predict high-magnitude thinning of lithospheric mantle during the early stages of extension. Conductive heating of lower crust directly preceded mantle exhumation and crustal excision, suggesting that thermal weakening of the lithosphere promotes focusing of extensional strain.

Corrosion characteristics of Fe3Si intermetallic coatings prepared by molten salt infiltration in sulfuric acid solution

Alloyed Fe3Si intermetallic compound coatings were prepared through non-electrolysis high-temperature infiltration in molten salt on the surface of AISI420 and AISI304 stainless steel containing Cr and Cr, Ni elements, compared with Fe3Si coating on A3 carbon steel surface. The microstructure of infiltration coatings was examined by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and glow discharge optical emission spectroscopy. The electrochemical corrosion properties and behavior of Fe3Si coatings in H2SO4 solution were evaluated via electrochemical techniques and static immersion tests. The results revealed that the permeation coatings prepared on the stainless steel surface are composed of a Cr- and Cr-, Ni-alloyed Fe3Si intermetallic-compound layer and a diffusion layer. Owing to the presence of alloying elements Cr and Ni from the substrate, the permeation coatings were relatively thick, dense, and contained only a few defects. The Cr-, Ni-alloyed Fe3Si coating prepared on AISI304 surface was the most compact, contained fewer defects, and was thicker than the coating prepared on AISI420. The Fe3Si infiltration coatings exhibited significant passivation characteristics in 10 vol% H2SO4 aqueous solution. Alloyed Fe3Si coatings of AISI420 and AISI304 exhibit better corrosion resistance in 10 vol% and 20 vol% H2SO4 than the Fe3Si coating of carbon steel. Therefore, these coatings can protect both types of stainless steel from surface corrosion. The best corrosion resistance was realized for the alloyed Fe3Si coating on AISI304 surface. The corrosion resistance and protection performance of Fe3Si intermetallic-compound coatings in H2SO4 solution are directly correlated with the thickness, compactness, defect characteristics, and passivation properties of the infiltration coatings. However, alloying elements from the alloy steel substrates had a significant effect on these four factors, during the infiltration process in the molten salt.

High temperature infiltration at low overpressures: Darcy’s law, the slug-flow hypothesis and percolation

Experiments on liquid metal infiltration into porous preforms at low overpressures give a linear relationship between the square of the infiltrated height and the applied over-pressure. This result can be derived from Darcy’s law under the Slug Flow Hypothesis SFH. Two features characterize SFH: (i) a step-like drainage curve, i.e., homogeneous, not necessarily full, filling of the empty space, and (ii) a linear drop of pressure through the infiltrated sample. However, experimental data do also indicate that, in most cases, (i) is not fulfilled. In this work, going beyond SFH, we utilize several combinations of drainage curve (Brooks and Corey, Van Genuchten and percolation) and permeability (Mualem, Burdine and a power law) to investigate whether the linear relationship may show up even though the SFH is not fulfilled. We show that, at low over-pressures, the integro-differential equation which describes this system admits a power law solution whose exponent and constant can be analytically related to the model parameters. This allows to predict that all combinations, except those including Burdine permeability, reproduce that linear relationship. In addition, the remaining six give a proportionality coefficient \(\ge \)1 as in SFH, actually is equal to 1 only for full filling (in the case of Mualem the coefficient of the drainage curve has to be \(\le \)1). However, only the two combinations based upon Percolation have a drainage curve with an exponent that can be less than 1, in agreement with recent experimental studies. Finally, albeit the drainage curve is not a step function, pressure approximately varies linearly throughout the infiltrated sample. The present analysis and methodology may be of help in a variety of fields such as soil science, oil extraction, hydrology, geophysics, metallurgy, etc.

Effect of sintering parameters on the microstructure and thermal conductivity of diamond/Cu composites prepared by high pressure and high temperature infiltration

Pure Cu composites reinforced with diamond particles were fabricated by a high pressure and high temperature (HPHT) infiltration technique. Their microstructural evolution and thermal conductivity were presented as a function of sintering parameters (temperature, pressure, and time). The improvement in interfacial bonding strength and the maximum thermal conductivity of 750 W/(m·K) were achieved at the optimal sintering parameters of 1200°C, 6 GPa and 10 min. It is found that the thermal conductivity of the composites depends strongly on sintering pressure. When the sintering pressure is above 6 GPa, the diamond skeleton is detected, which greatly contributes to the excellent thermal conductivity.

Post-emplacement fluids and pluton thermobarometry: Mount Stuart batholith, Washington Cascades

The effects of post-emplacement infiltration of externally derived, high-temperature fluids into arc-related batholiths are often not well characterized. Such infiltration can have far-reaching effects on the elemental and light isotopic chemistry of a batholith and on its mineral phases. At high temperature, fluid infiltration can be less easily detected, especially if widespread. The Mount Stuart batholith of the Washington Cascades is offered as an example of high-temperature infiltration of high δ18O fluids derived from its contact aureole. Some of the fluid infiltration coincided with and may have been partly derived from a kyanite-grade, post-emplacement metamorphic event that affected northern portions of the batholith. However, the effects of the fluid infiltration were far reaching and affected the entire margin of the batholith, including southerly portions that did not experience post-emplacement metamorphism. The result led to an oxygen isotopic zonation of the batholith, which is viewed as secondary in origin, with expected effects on mineral chemistry, including derived estimates of thermobarometry, a portion of which is also substantially subsolidus in origin. Our revised emplacement barometry of the Mount Stuart batholith, excluding areas affected by fluid infiltration, demonstrates that it was emplaced at ∼350–400 MPa. Soon after emplacement, the batholith was tilted to the north by loading processes and subsequently was righted and unroofed during erosion in the Eocene. Its current near palaeohorizontal orientation has implications for palaeomagnetic studies supporting northward transport (the Baja–British Columbia hypothesis), but these results need further study, given the batholith's complex metamorphic and deformation history and the nature of its dominant magnetic mineralogy (pyrrhotite).

High-Temperature Infiltration of Non-Metallic Articles Produced via Selective Laser Sintering

There are several commercial processes for producing metallic parts by selective laser sintering (SLS) followed by infiltration of a molten metal at 700-900C. These parts are used in rapid manufacturing and rapid tooling applications. The present work centers around research to produce non-metallic parts infiltrated with materials at temperatures exceeding 1300C. Specific systems include siliconized silicon carbide. Of primary concern are: process control during the high-temperature infiltration; the binder system which must bind powder together during SLS, provide structural strength continuously from room temperature to the infiltration temperature, and react favorably with the infiltrant. This research was funded by State of Texas Technology Development and Transfer Grant Number 003658.

Low temperature polymer infiltration for rapid tooling

Common infiltration methods used in rapid tooling have certain limitations viz., cracks, distortion and shrinkage caused by high temperature infiltration. Poor surface quality is also a limitation of conventional infiltration techniques. The high temperatures involved in conventional infiltration techniques make the process more expensive, complex and difficult to control. To overcome these difficulties, as well as to generate tooling for a small batch production, a low temperature polymer infiltration method has been developed in conjunction with existing rapid tooling techniques. Based on the curing principles of polymer materials, several infiltration materials were selected and their mechanical and chemical characteristics were investigated. To determine the necessary amount of polymer materials and infiltration height in the sintered mold an infiltration model is derived and results compared with experimental data. Testing results have shown significant improvements in the thermal resistance and mechanical properties of the rapid tool as a result of the resin infiltration.

High-Temperature Fluid-Rock Interaction and Scapolitization in an Extension-Related Hydrothermal System, Mary Kathleen, Australia

In the polymetamorphic Mary Kathleen Fold Belt, at the centre of the Proterozoic Mount Isa Inlier, Queensland, an early phase of extension (1760–1730 Ma) resulted in intrusion of voluminous granitic and doleritic magmas into the carbonate-evaporite-dominated Corella Formation at ∼5–10 km depths. Widespread high-temperature metasomatism ensued, involving scapolitization in dolerite, formation of albite-scapolite shear zones in granite, exo- and endoskarn formation, and a zone of K−Na−Ca alteration in the lowermost Corella Formation. Granites and dolerites were altered to an unusual Na−Ca-rich bulk composition, reflecting high-temperature infiltration of highly saline, chemically reactive externally derived fluid. The alteration products and their distribution suggest not only reaction of magmatic/aqueous fluids with the country rocks but also extensive halite dissolution and recirculation of saline fluids back into the intrusive bodies. The bulk of fluid flow occurred at high temperatures (500–700 °C), and major element and isotopic fronts were generally not smoothed out by the effects of temperature gradients, with the exception of one part of the system which shows evidence for up-temperature fluid flow. Analysis of oxygen isotopic data and the position of isotopic and geochemical fronts reveals time-integrated fluid fluxes of up to 2 × 104 m3/m2 for the metasomatism. Although very high salinities (up to 50 mol% NaCl) were attained by evaporite dissolution, δ18O values of most alteration products are in the range 7–12%, reflecting a predominance of oxygen derived from an igneous fluid. The position and interrelationships of metasomatic and isotopic fronts indicate an earlier stage of infiltration dominated by fluid released from crystallizing granite (with δ18O 10–12%), and a later stage (δ18O 7–9%) in which fluid had already interacted with halite and a mixed mafic-felsic igneous source or was repeatedly circulated between these rock types during alteration. The data reflect only a minimal contribution from fluids produced by devolatilization of the abundant carbonate-bearing rocks in the Corella Formation, and there are substantial areas of Corella Formation rocks that have escaped metasomatism during this phase of intrusion-related hydrothermal activity and during the subsequent regional metamorphic overprint. Along with the requirement that the fluids dissolved large amounts of halite from the same sequence, and the structural observations, we favour a model where fluid was preferentially channelled along specific permeable conduits, including former evaporite layers, before interaction with the now exposed altered rocks. Fluid was probably driven by both convective circulation and dilatancy-related deformation accompanying emplacement of magmas into a major crustal extensional décollement.