Conventional Cermet Research Articles

Degradation and Reactivation of Ni-Doped Strontium Iron Titanate Solid Oxide Cell Fuel Electrodes

Compared with conventional cermet solid oxide cell fuel electrodes, perovskite electrodes have the advantages of redox stability, coking resistance and sulfur resistance. Moreover, cation exsolution, where metal nanoparticles exsolve from the parent perovskite oxide under reducing conditions, has been shown to significantly enhance the electrochemical performance of the perovskite fuel electrodes due to the surface decoration of highly dispersed, catalytically active metal nanoparticles. Unfortunately, the phase transition of perovskite electrodes with time under different fuel conditions and its effect on their durability have not been fully understood. Furthermore, the phase and microstructure transformation of these exsolved perovskite electrodes under redox cycles still need more investigation.Here durability test of Ni-doped strontium iron titanate (STFN) was conducted at 850oC under different fuel conditions and redox cycles were introduced during these life-tests. Degradation in both ohmic resistance (R0) and polarization resistance (Rp) was observed during aging in 97% H2 + 3% H2O, and the introduction of wet Ar after 240-hour aging successfully recovered some of the electrochemical performance of STFN. In-situ X-ray diffraction shows the formation of Ruddlesden-Popper phase together with Ni-Fe alloy exsolution upon exposing to 97% H2 + 3% H2O and the change in composition over time was also observed. Scanning electron microscopy also shows coarsening of exsolved nanoparticles and microstructural change of perovskite electrodes. Moreover, life tests of STFN were also conducted in 50% H2 + 50% H2O and 50% H2 + 50% H2O at 850oC. Despite the more Ni-rich exsolved nanoparticles due to the higher oxygen partial pressure, the durability was worse than that of 97% H2 + 3% H2O. The increased degradation rate was attributed to the microstructural change of the parent perovskite phase.

Ni-Alloy Fuel Electrodes for Reversible Solid Oxide Cells

Reversible solid oxide cells (r-SOCs) are devices that can operate efficiently in both fuel cell and electrolysis operation modes. Nickel is widely used as an anode in conventional solid oxide fuel cells (SOFCs), but this agglomerates due to redox cycling, leading to irreversible performance degradation, making it unsuitable for r-SOCs. Here, we apply alternative electrodes to r-SOCs, in which Ni-Co alloy functions as a catalyst and an electronic conductor, whilst Ce0.9Gd0.1O2 (GDC) functions as a mixed ionic-electronic conductor. The electrochemical performance of these Ni-Co-GDC electrodes and their reverse-operation durability in r-SOCs are evaluated, and the effect of varying the amount of Co is investigated, compared with conventional cermet fuel electrodes. These novel materials exhibit high electrochemical performance and durability against SOFC/SOEC reverse-operation cycling.

Strong yet Ductile High Entropy Alloy Derived Nanostructured Cermet.

Cermet is an important composite composed of ceramics and metals, which has widespread engineering applications but is notoriously known for its poor ductility. This work synthesizes freestanding cermet nanosheets through the reaction of high entropy alloy nanocrystals with the molecular structure of poly-vinyl alcohol, which results in a unique nanostructure consisting of metallic nanocrystals surrounded by complex amorphous ceramics. Atomic force microscopy indentation shows that such a high entropy alloy derived cermet is strong and tough at ambient temperature with a superb strength (∼3.2 GPa) and excellent ductility (∼50%), therefore overcoming the long-standing issue of brittleness facing conventional cermets.

High-performance Ti(C,N)-based cermet with ZrO2 whiskers and Al0.3CoCrFeNi high-entropy alloy

In this study, a high–performance Ti(C,N)-based cermet was prepared by vacuum hot-press sintering technology using Ti(C,N) as the hard phase material, WC, TaC and Mo2C as the second-phase carbides, Al0.3CoCrFeNi high-entropy alloy (HEA) as the metal binding phase and ZrO2 whiskers as the reinforcement phase. The effects of whiskers and the HEA on the room-temperature and high-temperature properties of cermets were studied, including oxidation resistance, hardness, bending strength, fracture toughness and frictional wear properties. The research showed that the high-temperature properties of cermets were improved by ZrO2 whiskers and HEAs compared to those of conventional cermets with Ni/Co as the binding phase. The mechanisms for the weakening of cermets at high temperatures were grain boundary softening and material oxidation. Moreover, the high-temperature strengthening mechanism was attributed to the strength of the grain boundaries in the cermet, high–temperature hardness and oxidation resistance of the HEA binding phase, as well as the strengthening of the ZrO2 whiskers at high temperatures. The results proved that the wear mechanism of cermet materials was adhesive wear at high temperatures.

Highly flexible solid oxide fuel cells using phase-controlled electrolyte support

Flexible solid oxide fuel cells (SOFCs) have attracted increasing attention due to their excellent mechanical stability and lightness. An essential electrolyte material for developing highly flexible SOFCs is 3 mol% yttria-stabilized zirconia (3YSZ), but there remain some difficulties in its application to SOFCs. We report a phase-controlled, bendable, ultra-thin 3YSZ electrolyte with a thickness of ~22 µm, high flexural strength, and improved ohmic resistance that surpasses that of 8 mol% YSZ electrolytes. A flexible cell (total thickness < 60 µm) is fabricated through simple and reproducible methods such as tape casting and screen printing. The highest cell performance is achieved among the reported flexible SOFCs, with the maximum power density of 0.86 W cm−2 at 900 °C using conventional cermet electrodes, Ni-YSZ anode, and LSM-YSZ cathode. Our study provides a well-defined framework for developing flexible SOFCs as next-generation power sources for mobile devices with high volumetric power.

Al-Doped SrMoO3 Perovskites as Promising Anode Materials in Solid Oxide Fuel Cells.

Two perovskite materials with SrMo1−xAlxO3−δ (x = 0.1, 0.2) compositions have been synthesized by reduction from the corresponding scheelite phases, with SrMo1−xAlxO4−δ stoichiometry; the pertinent characterization shows that the defective perovskites can be used as anode materials in solid oxide fuel cells, providing maximum output power densities of 633 mW/cm2 for x = 0.2. To correlate structure and properties, a neutron powder diffraction investigation was carried out for both perovskite and scheelite phases. Both perovskites are cubic, defined in the Pm-3m space group, displaying a random distribution of Mo and Al cations over the 1a sites of the structure. The introduction of Al at Mo positions produced conspicuous amounts of oxygen vacancies in the perovskite, detected by neutrons. This is essential to induce ionic diffusion, providing a mixed ionic and electronic conduction (MIEC), since in MIEC electrodes, charge carriers are combined in one single phase and the ionic conductivity can be one order of magnitude higher than in a conventional material. The thermal expansion coefficients of the reduced and oxidized samples demonstrated that these materials perfectly match with the La0.8Sr0.2Ga0.83Mg0.17O3−δ electrolyte, La0.4Ce0.6O2−δ buffer layer and other components of the cell. Scanning electron microscopy after the test in a real solid oxide fuel cell showed a very dense electrolyte and porous electrodes, essential requirements for this type of fuel. SrMo1−xAlxO3−δ perovskites are, thus, a good replacement of conventional biphasic cermet anodes in solid oxide fuel cells.

The first observation of Ni nanoparticle exsolution from YSZ and its application for dry reforming of methane

Ni nanocatalysts produced through exsolution have shown strong resistance to particle sintering and carbon coking in a beneficial dry reforming of methane (DRM) reaction utilizing greenhouse gases such as CH4 and CO2. However, most of the existing oxide supports for exsolution have been limited to perovskite oxide, while studies on fluorite support have been rarely conducted due to the limited solubility despite its excellent redox stability. Here we demonstrate that 3 ​mol% Ni can be successfully dissolved into the yttria-stabilized zirconia (YSZ) lattice and be further exsolved to the surface in a reducing atmosphere. The YSZ decorated with exsolved Ni nanoparticles shows enhanced catalytic activity for DRM reaction compared to the conventional cermet type of bulk Ni-YSZ. Moreover, the catalytic activity is extremely stable for about 300 ​h without significant degradation. Overall results suggest that the YSZ-based fluorite structure can be utilized as one of the support oxides for exsolution.

When Cermet Applied for Hard Machining of Steel: A Review

Providing an information deals with the application of Ceramic Metal (Cermet) as a cutting tool applied for hard machining of steel is the objective of this review paper. Cermet is made of hard metals and was introduced just after the invention of Cemented Carbide. As a cutting tool, the conventional Cermet was known as TiC-based Cermet. Unfortunately, it was not as successful as Cemented Carbide due to its brittleness of low fracture toughness of TiC substrate. Thanks to TiN material. The addition of TiN improved the fracture toughness, and the modern era of Cermet was begun. A TiCN-based modern Cermet is characterized microstructurally by a structured hard phase featuring core-rim structure embedded in a tough Co-Ni binder. The effort to refine the fracture toughness of TiCN Cermet is discussed in this paper including the effort to raise its performance through coating technologies. In particular, its performance which is given in term of productivity and represented by volume of removal rate (VMR) is discussed. Finally, conclusions and recommendation for future works are written.

Colloidal processing and sintering of WC-based ceramics with low Ni content as sintering aid

To soften the extreme sintering conditions of Tungsten Carbide (WC), a 3 wt.% of metallic nickel (Ni) was added to the starting powders. To ensure a fair distribution of the second phase and an intimate mixture of the phases, the colloidal process was adopted. A commercial Ni and a in-house synthesised nanosized nickel were used as sintering aids. Rheological studies allowed a high dispersion of the nickel in the final composite powders. Sintering studies by Hot-Pressing route (HP) proved the great benefices of Ni as a sintering aid, decreasing the maximum temperature necessary to achieve full densification, from 1900 to 1450 °C and dwell times from 20 to 7 min. Among all the materials obtained, the best results in terms of density, microstructure and properties were obtained for WC-nNi, which achieved hardness of 14.8 GPa and toughness comparable to conventional cermets with much higher content of metallic phase.

Template- and Magnetic Field-Free Chemical Reduction of Ni Nanochains for Ni-Al2O3 Cermet Films: Growth Control, Characterization, and Application.

Cermet-based solar absorbers containing nickel (Ni) in a nanochain (NC) structure embedded in an aluminum oxide (Al2O3) film demonstrated a high absorptance of more than 90% of the solar spectrum. In this work, Ni NCs were successfully prepared by a simple chemical reduction method without the assistance of a template or magnetic field. The formation of Ni nanoparticles (NPs) in different configurations was controlled by adjusting the NaOH:NiCl2 molar ratio. Not only was NaOH used to adjust the solution pH but it also induced the reduction reaction to be faster and so resulted in a larger number of Ni nuclei. Together with the intrinsic magnetic property of Ni, Ni NPs tended to orient in a chain-like manner to form Ni NCs that remained stable throughout the reaction. Increasing the NaOH:NiCl2 molar ratio up to 8 led to a uniform morphology of Ni NCs. However, at higher molar ratios (above 8), the NCs were likely to collapse at the end of the reaction, forming near-globular particles. With its unique structure, metallic Ni NCs were employed by incorporating them into a ceramic layer of Al2O3, which can be used as efficient cermet materials. Compared to a conventional cermet with embedded spherical Ni NPs, a 16.4% increase in solar absorptance was observed with the Ni NCs due to their enhanced absorption and scattering in the solar spectrum. Moreover, increasing the Ni NC content in the Al2O3 layer gradually enhanced the solar absorptance to 0.91 and so was a good solar absorber.

Investigation of the oxidation behavior and high oxidation-resistant mechanism of Ti(C,N)-based cermets

The oxidation kinetics and mechanisms of Ti(C,N)-based cermets have been studied systematically in this work. The continuously stable NiCo2O4-spinel and (Co,Ni)WO4 film are the keys to providing essential reassurance for low oxidation rates in conventional cermets. After the addition of alloyed Cr, the oxidation weight gain of the cermet significantly decreased. The superior oxidation-resistant performance of Cr-doped cermet was a result of the formation of Cr(W,Mo)O4, which showed high stability and a high oxygen migration barrier energy. The distribution of Cr(W,Mo)O4 in the intermediate oxide layer reduced the ions mobility during the oxidation process.

Model-guided design of a high performance and durability Ni nanofiber/ceria matrix solid oxide fuel cell electrode

Mixed ionic electronic conductors (MIECs) have attracted increasing attention as anode materials for solid oxide fuel cells (SOFCs) and they hold great promise for lowering the operation temperature of SOFCs. However, there has been a lack of understanding of the performance-limiting factors and guidelines for rational design of composite metal-MIEC electrodes. Using a newly-developed approach based on 3D-tomography and electrochemical impedance spectroscopy, here for the first time we quantify the contribution of the dual-phase boundary (DPB) relative to the three-phase boundary (TPB) reaction pathway on real MIEC electrodes. A new design strategy is developed for Ni/gadolinium doped ceria (CGO) electrodes (a typical MIEC electrode) based on the quantitative analyses and a novel Ni/CGO fiber–matrix structure is proposed and fabricated by combining electrospinning and tape-casting methods using commercial powders. With only 11.5 vol% nickel, the designer Ni/CGO fiber–matrix electrode shows 32% and 67% lower polarization resistance than a nano-Ni impregnated CGO scaffold electrode and conventional cermet electrode respectively. The results in this paper demonstrate quantitatively using real electrode structures that enhancing DPB and hydrogen kinetics are more efficient strategies to enhance electrode performance than simply increasing TPB.

Preparation of highly toughened Ti(C,N)-based cermets via mechanical activation and subsequent in situ carbothermal reduction

Highly toughened Ti(C,N)-based cermets were successfully fabricated using a novel method of mechanical activation and subsequent in situ carbothermal reduction. The phase transformation, chemical composition, and microstructure of the mechanical activation powders and as-sintered cermets were investigated using XRD, ICP-AES, C/N/O analysis, and SEM. The results revealed that the complex MoNiTi solid solution phase formed after mechanical activation, and the powders after high energy ball milling promoted the solid solution of alloying elements into the hard particles. After the subsequent sintering process containing the in-situ carbothermal reduction reaction and liquid sintering, the microstructure of as-sintered cermet showed a single solid solution phase with a homogenous distribution. Without added WC, the extremely high toughness of the present cermet was 21.3 MPa·m1/2, and this was 66.4% higher than that of the conventional cermet and 62.5% higher than that of the cermet that was fabricated via in-situ carbothermal reduction.

Interfaces and mechanical properties of dual grain structure Ti(C,N)-based cermets prepared by in situ reduction of TiO2

Ti(C,N)-based cermets with dual grain structure were prepared by partially replacing coarse Ti(C,N) particles with TiO2 and carbon via in situ carbothermal reduction. The microstructure and interface structure of the samples were characterized using SEM, EDX, and TEM. With optimized TiO2 content, significant enhancements of the transverse rupture strength (3324 ± 52 MPa) and fracture toughness (18.6 ± 0.5 MPa m1/2) were obtained in the present cermets without losing much of the hardness. The orientation relationship and coherency state at both the rim/binder and rim/rim interfaces in the present cermets changed considerably compared with conventional cermets. Based on detailed analysis of the interface structure, it was demonstrated that interfacial characteristics were the dominant factors for the significantly increased strength and toughness in the present dual grain structured cermets. This study provided an effective method for obtaining an excellent combination of transverse rupture strength and toughness in cermets.

Effect of Mo addition mode on the microstructure and mechanical properties of TiC–high Mn steel cermets

In TiC- and Ti(C,N)-based cermets, the wettability of the ceramic phase with the metallic binder is commonly increased through supplementation with Mo in the form of pure Mo powder or Mo2C. Herein, TiC–high Mn steel cermets were fabricated by conventional powder metallurgy techniques using Fe–Mo pre-alloyed powders as binders to guarantee uniform Mo distribution, and the cermet preparation process was optimized and investigated in detail. The microstructures of the thus obtained cermets were observed by scanning electron microscopy and compared to those of a Mo-free cermet and a cermet prepared using pure Mo powder. The grain size of Fe–Mo powder cermets exceeded that of the Mo-free cermet but was much smaller and more homogeneous than that of the Mo powder cermet. For Fe–Mo powder cermets, angular and tetragonal TiC particles were observed at Mo contents of <1.2 wt%, while round shapes became dominant at higher Mo contents. The hardness of Fe–Mo powder cermets increased with increasing Mo content, as did transverse rupture strength, which was maximal (2264 MPa) at a Mo content of 2.4 wt%, while impact toughness was maximal (11.2 J/cm2) at a Mo content of 1.2 wt%. The above values exceeded those reported for similar conventional cermets, and the use of Fe–Mo pre-alloyed powder as a metallic binder was therefore concluded to be an attractive strategy of increasing the strength and toughness of TiC–high Mn steel cermets.

Effect of Fe–Mo–Cr pre-alloyed powder on the microstructure and mechanical properties of TiC–high-Mn-steel cermet

In the study, a TiC–high-Mn-steel cermet is fabricated using FeMo and Fe–Mo–Cr pre-alloyed powders as metallic binders by powder metallurgy techniques. The effect of Cr on the microstructure and mechanical properties of the cermet is studied and the cermet preparation process is optimized. The microstructure and fracture morphology of the cermets are observed with scanning electron microscopy, while phase identification and analysis are performed by X-ray diffractometry. The results show that the particles of Cr-free cermet are angular and polygonal, while those of cermet with added Cr are rounded and ellipsoidal. The grains of Cr-free cermet are larger than those of the Cr-added cermet, which is unlike similar conventional cermets. The grain size of the Cr-added cermet increases slightly with increased Cr content. In addition, the relative density of the cermet decreases slightly with increased Cr content. The hardness of cermet is maximized at HRC 64.8 with the Cr content of 1.0 wt%; with further increases in Cr, the hardness decreases gradually. The transverse rupture strength and impact toughness first increase and then decrease with increasing Cr content, reaching the maxima of 2355 MPa and 13.42 J/cm2, respectively, at the Cr content of 1.5 wt%. The strength and toughness of the cermet are improved greatly compared to those of conventional similar TiC–high-Mn-steel cermets.

New production of (Ti, W)C-based cermets toughened by in-situ formed WC and twinned (Ti, W)C platelets: Carbonization of the Nix(Ti0.6, W0.4)4C-type η phases

Toughening of (Ti, W)C-based cermets is one of the most important field to expand their application in cutting, Wear-resistant materials and equipment used in harsh environment. Modifying the morphology and composition of the ceramic grains is a highly effective measure. Here, we demonstrate a promising cermet toughened by in-situ formed WC or twinned (Ti, W)C platelets with large size around 5–8 μm. A new method is established by carbonization of synthesized η phases, via sintering of the high-energy crushed TiWNiC powders. Results showed that higher Ni/C ratio and temperature could boost the carbonization process, resulting in more Ni6(W1-x, Tix)6C. Only when Ni/C ratio was higher than 1.0, could WC platelets appeared in the cermets. TiC doped WC platelets with no planar defect began to be precipitated at a low temperature by two-dimension growth, along with the formation of fine spherical (Ti, W)C particles. Plate-like twinned (Ti, W)C was only formed by carbonization of Ni2(W1-y, Tiy)4C above 1200 °C, through the twin-assisted growth along {111} planes at a low supersaturation. Platelets could enhance the strength and toughness with slightly decreased hardness, via crack deflection and platelet pull out mechanisms. Compared to the conventional cermets, (Ti, W)CNi with high fracture toughness (15.80 MPa mm1/2), satisfactory strength (1885 MPa) and hardness (88.3 HRA) were achieved. This work provided not only a new method for preparing the (Ti, W)CNi cermets, but also a new insight to modify the final microstructure with controlled properties.

A comparative study on slurry erosion behavior of HVOF sprayed coatings

Este trabajo investiga el comportamiento del desgaste en mezclas erosivas de recubrimientos depositados mediante la técnica de proyección térmica usando el proceso HVOF. Se analizaron tres tipos de recubrimientos, WC-CoCr con estructura de grano fino, Cr3C2-NiCr 75-25 y NiCrWSiFeB, estos últimos con tamaños de grano convencional. Los ensayos de desgaste erosivo se desarrollaron usando un tribómetro de recipiente de mezclas para evaluar la resistencia a la erosión de los recubrimientos a velocidades de impacto de 3.61 m/s y 9.33 m/s y ángulos de impacto de 30 y 90º. El mecanismo de desgaste de los recubrimientos fue estudiado y discutido sobre la base del examen microestructural y la influencia de sus propiedades mecánicas. Se observó que el recubrimiento de carburo de tungsteno exhibe mejor resistencia a la erosión comparada con los recubrimientos de carburo de cromo y metálico debido a sus propiedades de microdureza, tenacidad a la fractura y menor porosidad.

Neural network analysis for erosive wear of hard coatings deposited by thermal spray: Influence of microstructure and mechanical properties

An artificial neural network (ANN) analysis is used to obtain a model to predict the rate of erosive wear of hard coatings deposited by two different kinds of thermal spray techniques. High Velocity Oxygen Fuel (HVOF) and Flame Spray FlexiCords (FS/FC) techniques were used under various operational conditions. Different microstructural features that control the mechanical and the tribological performances of three groups of deposits: tungsten carbide, chromium carbide and metallic alloy coatings, were analyzed. The ANN technique involves database use to predict erosive wear evolution, having a large number of variables like deposition process, impingement angles and velocity of the erosive particles, porosity, roughness, microhardness and fracture toughness. Commercially available powders were used as feedstock for coatings deposited by HVOF. Commercial cord wires were used in the FS/FC coating deposition. The slurry erosion testing was performed using a laboratory made pot-type slurry erosion tester, at impact velocity of 3,61m/s and 9,33m/s combined with impact angle of 30° and 90°. From the results, it was observed that the microhardness and fracture toughness, as a combination factor, have the greatest influence on erosive rate followed by porosity. Samples coated with WC-CoCr cermet coating with fine WC carbides exhibit higher erosion resistance as compared with the other conventional cermet and metallic alloy coatings, mainly because of its homogenous microstructure and improved properties like low porosity, high microhardness and high fracture toughness. The numerical results obtained via neural network model were compared with the experimental results. The agreement between the experimental and numerical results is considered a good aspect.

Low Ni-Containing Anodes Using Titanate-Based Perovskites for Methane Direct Internal Reforming Power Generation

Direct internal reforming SOFCs (DIR-SOFCs), which directly utilize hydrocarbons as fuels in the anode, can achieve high power generation efficiency due to chemical recuperation of the anodic reaction heat by endothermic reforming reactions. DIR-SOFCs often suffer from carbon deposition on the anode and the resultant severe degradation of power generation performance and stability [1]. Nickel contained in SOFC anodes as an electronic conductor acts as catalytic sites for carbon decomposition in the first step of hydrocarbon fuel conversion. Accordingly, these Ni-related issues can be lessened by reducing the Ni content in the anode. In this study titanate-based Ni-cermet anodes such as Ni-LaxSr1-xTiO3+ d (LST) have been investigated as an alternative anode to conventional Ni-YSZ cermets. LST is a mixed ionic and electronic conducting material with a relatively high electronic conductivity of the order of 10 S/cm2[2]. Ni-LST anodes were fabricated by a conventional method using a ball mill and by an impregnation method, and the stability as well as tolerance to carbon deposition of the anodes were evaluated. Titanate-based perovskites ware prepared via Pechini method. A desired amount of the respective nitrates and acetates were mixed with titanium isopropoxide and citric acid, and then dissolved in ethylene glycol. The mixture was heated to 150ºC on a hot stirrer to complete the polymerization of the mixture. The resultant powder was calcined in air at 800ºC for 3 h to form a perovskite oxide. The obtained powders were mixed with NiO particles at a desired ratio, and ball-milled for 24 h, followed by calcination at 1200°C for 5 h in air. The thus prepared cermets were pulverized into powder, and then mixed with polyethylene glycol to form slurry, with which an YSZ disk of 20 mm in diameter and 0.5 mm in thickness was painted in a circular shape of 6 mmφ as an anode using a screen. Then the disk was calcined at a desired temperature for 5 h in air. In addition, Ni cermets were prepared by an impregnation method. LST powders prepared by the Pechini method were impregnated with an aqueous solution of nickel nitrate on a steam bath at 80°C, dried, and then calcined at 1000 ºC in air for 2 h. Thus obtained Ni-LST powder was used to prepare the anode in the same manner as conventional cermets. Current-voltage characteristics of the anode was evaluated at 1000 ºC by feeding humidified H2 and dry O2 to anode and cathode, respectively, at 100 ml/min. Direct internal reforming power generation performance was measured by feeding steam-to-carbon ratio of 0.1 under constant current load of 200 mA/cm2. The durability of the cells was evaluated by AC impedance spectra measured under open circuit condition at 1000 ºC with a Princeton VersaSTAT3 in humidified H2 feed before and after the power generation at S/C = 0.1. Figure 1 shows current-voltage characteristics of SOFCs with Ni-LST and Ni-YSZ anodes prepared by the ball-mill and impregnation methods. The power generation characteristics of 60wt%Ni-LST prepared by the ball-mill method was slightly lower than that of 60wt%Ni-YSZ by the ball-mill method, but still high performance was observed over the 60wt%Ni-LST. On the other hand, when the nickel content was decreased to 40wt% in Ni-YSZ by the ball-mill, a significant deterioration of power generation characteristics was observed over the Ni-YSZ anode, while Ni-LST prepared by the impregnation method maintained power generation performance despite the low Ni content of 10wt%. The durability of 60wt%Ni-LST by the ball-mill method and 10wt%Ni-LST by the impregnation method was evaluated by feeding a steam-methane mixture at S/C = 0.1 at 1000 ºC under a constant current load of 200 mA/cm2. A gradual decrease in the terminal voltage appeared for 60wt%Ni-LST anode, and a large increase in the impedance was found on the impedance spectra after CH4/H2O direct reforming power generation. In contrast, 10wt%Ni-LST by the impregnation method exhibited a stable power generation characteristics under the low S/C of 0.1 and constant current load of 200 mA/cm2. The impedance became slightly smaller after the power generation.