Phase Evolution and Oxidation Resistance of YSZ/(Ni,Al) Composite Coatings in CH_4 Atmosphere

YSZ/（Ni, Al） composite coatings with different Ni：Al mole ratios were deposited on superalloy Inconel 600 by electrophoretic deposition（EPD） technique, followed by sintering in CH_4 atmosphere at 1 100 ℃for 2 h and isothermally oxidation at 1000 ℃ for 50 h. After sintering at 1100 ℃ for 2 h in CH_4 atmosphere, besides ZrC and t-ZrO_2 phases, the phase constitutes of Ni：Al mole ratios with 1：3, 1：2, and 1：1 were（Zr, Al）C, AlNi_3 and Ni phases, respectively. A remarkable difference in the oxidation behaviors of YSZ/（Ni, Al） composite coatings with different Ni：Al mole ratios was observed. For YSZ（Ni：Al=1：3） coated sample, oxidation at 1000 ℃ causes decomposition of the（Zr,Al）C solid solution to metallic Al, and then most of the Al is oxidized to Al_2O_3. For the YSZ（Ni：Al=1：2） coated sample, oxidation at 1000 ℃ mainly causes decomposition of the AlNi_3 phase. For YSZ（Ni：Al=1：1） coated sample, after oxidation at 1000 ℃, most of the Ni is oxidized to Ni O phase, and tolerated 50 h of oxidation and finally cracked and spalled from the specimen. YSZ（Ni：Al=1：3） and YSZ（Ni：Al=1：2） coated samples show superior oxidation resistance than that of YSZ coating. The different oxidation resistance mechanisms of YSZ/（Ni, Al） composite coatings sintered in CH_4 atmosphere were discussed.

Improving CNT-Si solar cells by metal chloride-to-oxide transformation

Transitional metal oxides(TMOs)are important functional materials in silicon-based and thin-film optoelectronics.Here,TMOs areapplied in carbon nanotube(CNT)-Si solar cells by spin-coating solutions of metal chlorides that undergo favorable transformation in ambient conditions.An unconventional change in solar cell behavior is observed after coating two particular chlorides(MoCl,and WCls,respectively),characterized by an initial severe degradation followed by gradual recovery and then well surpassing the original performance.Detailed analysis reveals that the formation of correspondina oxides(MoOa and WO.)enables two primary functions on both CNTs(p-type doping)and Si(inducing inversion layer),leading to significant improvement in open-circuit voltage and fill factor,with power conversion efficiencies up to 13.0%(MoOg)and 13.4%(WOg).Further combining with other chlorides to increase the short-circuit current,ultimate cells efficiencies achieve>16%with over 90%retention after 24 h,which are among the highes stable efficiencies reported for CNT-Si solar cells.The transformation of functional layers as demonstrated here has profoundinfluence on the device characteristics,and represents a potential strategy in low-cost manufacturing of next-generation high efficiency photovoltaics.

Phase transformation of ZrO2 doped with CeO2

Thermal barrier coatings（TBCs） protection is widely used to prolong the lifetime of turbine components.The outermost layer of TBCs is ceramic layer, whose function is heat insulation, and the main composition of the ceramic layer is ZrO2. In this study, the micro-Zr02 and the nano-ZrO2 doped with 10 wt% CeO2 as well as microZrO2 and nano-ZrO2 were prepared by air plasma spraying（APS） to study the advantages of the addition of rare earth element. The effect of CeO2 on the phase transformation of ZrO2 was studied. The results show that there are few cracks in micro-and nano-ZrO2 doped with 10 wt% CeO2,and rare earth oxides can affect the phase transformation significantly. The morphologies, hardness and elastic modulus of the four ceramic layers were also discussed.

Effect of Chemical Composition on Oxide Transformation and MnS Precipitation Upon Oxide Particles in Fe-Cr Alloy by Heat Treatment

The transformation of nonmetallic inclusions and the change of MnS precipitation ratio on oxide particles during heat treatment were studied by using Fe-10%Cr alloy containing different Si and S content in the present study. The phenomenon of oxide transformation in alloy in this research was characterized according to Si content. When the Si content was lower, the typical inclusions changed from MnO?SiO2 type to MnO?Cr2O3 type by heat treatment. In the case of high S concentration, the obvious MnS area in inclusions was observed after heat treatment. It was more favorable for MnS precipitation as the S content was improved from approximately 20×10-6 to 60×10-6. The MnS precipitation ratio on oxide particles was higher on MnO?SiO2 type than MnO-Cr2O3 type oxide particles. Besides, the ratio on the two kinds of oxides increased with increasing the time for heat treatment at 1473K as a whole. The theoretical Mn content at which MnS can precipitate agrees well with the experimental results.