Abstract: Ti(C,N)-based cermets were coated with a TiN/TiAlN coating using ion plating technology.
The sliding wear test was performed for the coated cermets and the microstructure, composition and
surface roughness of the coated cermets under different velocities and loads were characterized. The
results showed that the friction coefficients of the coated cermets were lower than that of the neat cermets.
Under the same load, the adhesion phenomenon of the counterpart materials on the specimens was
improved and the mean friction coefficient increased with increasing sliding speed. Under the same
sliding velocity, the average friction coefficient of the coated cermets was lower under higher load. The
wear mechanisms were mainly adhesive wear and abrasive wear.
Abstract: TiN/NbN multilayers on steel substrates (SKD11) are produced using DC magnetron
sputtering process. The multilayer obtained are characterized in composition by means of X-ray
diffraction techniques, Microhardness and adhesion to the substrate were studied by atomic force
microscopy and scratch tests. The morphological analysis and coating structure are studied using
scanning electron microscopy, and atomic force microscopy. The film thickness is measured by a stylus
profiler (XP-2 stylus profiler). Wear tests were performed on pin-on-disk configuration and dry sliding
conditions, at 5N load by using hardened steel ball. On mechanical properties, higher Young’s modulus
and hardness values follow to increase the TiN/NbN layers number. The multilayer films of 64 layers at
500°C 1h annealing indicated that the microhardness and Young’s modulus had the highest values.
Abstract: Ti(CN) -based ceramics coating was deposited on TC4 titanium alloy substrate using the
home- made reactive electric spark deposition system, which is under nitrogen-sealed atmosphere and
using the graphite electrode. It was showed that: (1) the single-pulse deposition zone presents irregular
spattering shape and the phase of coatings was made up of TiC0.51N0.12 spherocrystal and dendritic crystal,
Ti0.80V0.20 and C, (2) metallurgical bond between coating and substrate is realized, (3) the Ti(CN) ceramic
particle, whose average grain size is 626nm, distributes dispersively among the coating and is in-situ
synthesized by the reaction among titanium from the substrate, carbon from the graphite electrode and
nitrogen from the shielding nitrogen gas.
Abstract: The applications of titanium and titanium alloys under severe wear conditions are highly
restricted due to their low hardness and poor tribological properties. To improve the hardness and wear
resistance, laser cladding of commercial purity titanium was carried out with a 5 kW continuous wave
CO2 laser. WC powders and Ti powders were mixed for cladding in different proportions. The phases of
clad layer were characterized by scanning electron microscopy, X-ray diffractometer and energydispersive
X-ray spectroscopy. The mechanism of the reaction between melted WC and Ti is discussed.
Abstract: Three compositions, (Ni75Si25)-5Cr, (Ni75Si25)-10Cr and (Ni75Si25)-15Cr, have been
cladded onto Ni-based suaperalloy substrate by pre-placing laser cladding process with a 5 kW
continuous wave CO2 laser. Ni75Si25 was also cladded with the same method for comparison. The
process parameters have been optimized to obtain defect free claddings. The microstructure and the
hardness of the cladded layers were characterized by optical microscopy, scanning electron microscopy,
X-ray diffraction and microhardness measurement. The corrosion resistance of the cladded layers was
measured in a sulfuric acid solution.
Abstract: Nanostructured surface layer was produced on the Ti-6Al-4V alloy by surface mechanical
attrition treatment (SMAT) technique, and then the ceramic composite coatings of surface nanocrystallization/
micro-arc oxidation (SNC/MAO) were prepared on the nanocrystallized surface of
Ti-6Al-4V alloy by pulsed single-polar micro-arc oxidation in NaAlO2 solution. The phase composition,
morphology of surface and section and element content of the nanostructured surface layer and the
ceramic coatings were investigated by XRD, TEM, SEM and EDS, respectively. The results showed that
after the SMAT technique treatment for a short period of time, the surface layer was refined into ultrafine
grains. The thickness of the coatings on the substrate treated by SMAT technique is about 10μm by
micro-arc oxidation, which is thicker than the ones on the substrate untreated by SMAT technique, and
the ceramic coatings are mainly composed of Al2TiO5. Besides, a bright interface layer comes out
between the substrate and the coating when the substrate treated by SMAT technique. The influences of
the SMAT technique on the surface morphology of the ceramic coatings also changed. The coatings using
the SMAT technique were more compact and less porous than the ones on the substrate untreated by
SMAT technique. The content of elements in the nanostructured surface layer on Ti-6Al-4V alloy had
changed after the SMAT technique: the content of Ti increased, the content of V decreased, and the
content of Al changed a little. The contents of Al and P in the coating increased while the content of Ti
Abstract: Thermal conductivity of zirconia and yttrium stabilized zirconia (YSZ) is calculated with
perturbation molecular dynamics method (PMD). The results showed that thermal conductivity of YSZ is
lower than that of pure zirconia and PMD is a very effective way in thermal conductivity calculation for
ceramics. In higher temperature region, the calculated values show a different tendency with the
experiment ones, which is because that photon conduction is not considered in PMD method. By taking
photon effects into account, the calculated thermal conductivity curve is found fairly well coherent with
measurements. In addition, the thermal expansion of zirconia is also presented by calculating the volumes
at different temperatures. The results and methods in this paper have been proved to be very helpful in
further design of new ceramic materials in the field of thermal barrier coatings (TBCs).
Abstract: Based on La2Zr2O7 ceramic for thermal barrier coatings, LaSmZr2O7 ceramic doped with
samarium ion was successfully prepared using solid state reaction method. The pellets were sintered at
1600°C for 10 hours in air. The phase structure, thermal conductivity and thermal expansion coefficient
of LaSmZr2O7 ceramic and La2Zr2O7 ceramic were measured by XRD, laser-flash device,
high-temperature dilatometry, respectively. The results show that the crystal structure of LaSmZr2O7
ceramic is not affected by the doped samarium ion in the zirconium lattice. The thermophysical results
show that the thermal conductivity of the LaSmZr2O7 ceramic is lower than that of La2Zr2O7 ceramic,
while the thermal expansion coefficient is higher than that of La2Zr2O7 ceramic. These results indicate
that LaSmZr2O7 ceramic or Ln2Zr2O7 ceramics doped with other rare earth ions could be candidate
materials for future thermal barrier coatings.
Abstract: Pyrochlore structure oxide (La0.5Sm0.5)2(Zr0.9Ce0.1)2O7 was prepared by mixing the appropriate
amounts of ZrO2, La2O3, Sm2O3 and CeO2, followed by reacting at 1600°C for 10 h. It was shown that the
thermal conductivity was much lower than that of 8YSZ, which was mainly ascribed to the oxygen
vacancies and lattice strain in lattice of (La0.5Sm0.5)2(Zr0.9Ce0.1)2O7.
Abstract: A complex rare-earth zirconate (La0.4Sm0.5Yb0.1)2(Zr0.7Ce0.3)2O7 powder for thermal barrier
coatings (TBCs) was synthesized by coprecipitation method. The phase composition, microstructure and
the thermophysical properties were investigated. XRD results revealed that single phase
(La0.4Sm0.5Yb0.1)2(Zr0.7Ce0.3)2O7 with pyrochlore structure was prepared and the SEM result showed that
the microstructure of the product was dense and no other phases existed among the particles. With the
temperature increasing, the thermal expansion coefficient (CTE) of the ceramic increased, while the
thermal conductivity decreased. The results indicated that CTE of the ceramic was slightly higher than
that of La2Zr2O7 and the thermal conductivity of the ceramic was lower than that of La2Zr2O7. These
results imply that (La0.4Sm0.5Yb0.1)2(Zr0.7Ce0.3)2O7 can be explored as the candidate material for the
ceramic layer in TBCs system.