Advanced memory technologies are in demand with phase change memory (PCM) devices as a forefront candidate. For successful characterization by transmission electron microscopy (TEM) for failure analysis and device development, an accurate and controllable thinning of TEM specimens is critical. In this work, TEM specimens from a GeTe-based PCM device at a partial SET state were prepared using a Xe plasma focused ion beam (pFIB) and polished to electron transparency using Ar ion beam milling. We will highlight the differences between Ga focused ion beam (FIB) and Xe pFIB TEM specimen preparation, the benefits of post-pFIB Ar ion beam milling, and show TEM results of the effects of partial SET programming of the GeTe PCM device.

In order to improve the quality of coating, the causes of defect are analyzed in this paper. The research innovative uses single factor experiment combined with MATLAB to fit out the relationship between porosity and laser power, scanning speed, thickness, overlap rate. The multivariate quadratic equation is derived in this paper. It provides a solution to avoid defects in the aspect of laser cladding process.

Solid oxide fuel cell (SOFC) has been developed for a hundred year and met a great challenge on material design and marketing. In recent years, new SOFC materials are dug up to achieve high energy-output performance at lower working temperature (300~600 °C), namely low-temperature SOFC (LTSOFC). In this study, Ni-Co-Al-Li oxide (NCAL) was used for making dense, thin and uniform coatings on grooved bipolar electrode substrate for LTSOFC. Low-pressure plasma spray (LPPS) technology was applied to manufacture the NCAL coatings. The performance of a fuel cell package using the coated bipolars was tested between 350 and 600 °C, showing 6~8 W power output with 4 single fuel cells (active area of 25 cm 2 ). The LPPS technology is believed to be one of the ultimate ways for manufacturing the thin film/coatings for SOFC applications in future.

As a new processing technology, plasma spray physical vapor deposition (PS-PVD) is capable to deposit coatings out of the vapor phase with high deposition rate. Moreover, the resulting quasi-columnar coatings were unique, hardly deposited by other process. Due to its low thermal conductivity and excellent superior strain tolerance, quasi-columnar coatings attract much attention in the thermal barrier coatings (TBCs) field. In this paper, the morphology variation of the quasi-columnar yttria stabilized zirconia (YSZ) coatings deposited under different conditions was investigated. Combined the morphology of the initial deposits during short time spraying, the deposition mechanism of quasi-column microstructure was concluded. It can be found that the quasi-column coating was formed by co-deposition of vapor phases and solid particles. The vapor phase can develop into column, while the solid particles not only intensified the shadowing effect but also destroyed the nucleus during vapor deposition.

SiC coatings were prepared with pack powder in different particle sizes in a vacuum atmosphere by pack cementation technique to protect the C/SiC composites substrate from oxidation. The phase and microstructure of the coatings were investigated by XRD, SEM analyses. The relationship between powder granularity in the pack and microstructure of SiC coatings was studied. Cyclic oxidation test at 1573K in air atmosphere was performed and the effect of powder particle size in the pack on high-temperature oxidation resistance of SiC coatings was discussed in detail. It is observed that with powder granularity in the pack increasing thickness and density of SiC coatings increases, corresponding oxidation resistance of the coating is improved. Possible mechanisms related to oxidation were preliminarily discussed.

The ZrO 2 -7%Y 2 O 3 powder produced by domestic company was used to make dense vertically cracked (DVC) thermal barrier coatings (TBCs) via the High energy plasma spray system. The influence of preheating temperature of substrates, the thickness of single deposition and spray power on the microstructure of the coatings was studied in detail. The porosity of the thermal barrier coatings prepared by Delta gun was 2.8%-7.3% and bonding strength of the coatings was 20-30MPa. The results demonstrated that the TBCs with DVC structure had excellent thermal shock resistance, and the 1100°C thermal shock lifetime was 206 cycles, which was obviously better than different coating structure by conventional APS (life less than 100 cycles). The mechanism of the failure of the TBCs in the thermal shock process was investigated.

A commercial abradable coating AlSi-hBN was fabricated by atmospheric plasma spraying and was thermal aged at 450 °C in the atmospheric environment for 1000h. Thermal aging effect on coating abradability, hardness, bond strength and microstructure were evaluated. It was found that coating abradability increased obviously after 2h thermal aging and slightly decreased for extended thermal aging time. A sharp decrease in both coating hardness and bond strength were found after 2h thermal aging and a slow increase occurred with the extended aging time. Relationships between coating properties and microstructure were studied. Decomposition of organic binder and sintering of AlSi matrix metal generated by thermal aging were found to be reasons for coating properties changes.

The Ti 2 AlNb blade is used in high pressure compressor aero-engines to provide high thrust force at relatively light weight. A series of abradability tests was carried out on CuAlNi-graphite, NiCrAl-graphite, NiCrAl-bentonite, and NiCrFeAl-hBN abradable coatings rubbed against Ti 2 AlNb dummy blades with the maximum blade-tip velocity of 300 m/s at 500 °C. In consideration of the effects of an engine’s working conditions, some tests were conducted with incursion rate as the single variable. The scratched surfaces of the samples were observed by the stereoscopic optical camera, and a ratio of the blade wear to shroud incursion depth (IDR) was evaluated to characterize the abradability of coatings. The results show that NiCrAl-graphite and NiCrFeAl-hBN abradable coatings perform very well rubbed against the Ti 2 AlNb blade, and the blade-tip wear is not obvious after abradability tests.

Thermal barrier coatings (TBCs) consisting of a MCrAlY bond coat and a YSZ topcoat were air plasma sprayed onto Hastelloy X substrates. Samples were thermally cycled between 100 °C and 1100 °C and thermal fatigue failures were investigated via microstructure analyses. Final fatigue failure was caused by the formation of interface-parallel cracks in the topcoat, which was found to strongly related to the oxidation behavior of the bond coat. The development of oxide layers was therefore studied in detail and a thermo-kinetic model was used to explore the role of elemental diffusion in oxide formation.

High-purity nanocrystallized YSZ powders were used to manufacture thermal barrier coatings by air plasma spraying. After spraying, the coating samples were aged at temperatures of 1200, 1300, and 1400 °C. Coating samples made from ordinary YSZ powders were aged at the same temperatures. XRD analysis shows significant tetragonal-to-monoclinic phase transformation in the reference coatings after 100 h at 1400 °C in contrast to the phase stability exhibited by high-purity YSZ. The sintering behavior of the YSZ coatings was also examined along with the influence of MCrAlY oxidation.

In this study, 1-1.5 μm chromium carbide particles are used to prepare CrC-NiCr and CrC-Ni-Cr powders by spray drying and vacuum sintering with the aim of optimizing the properties while minimizing the cost of HVOF-sprayed NiCr-CrC coatings. The powders are characterized by means of SEM and XRD analysis and the coatings are evaluated based on microstructure, microhardness, bonding strength, and erosion resistance.

A series of abradability tests were conducted on AlSi-hBN coatings, which are commonly used in the compressor section of aeroengines for clearance control. The coatings were sprayed on test plates to a thickness of 1.9-2.0 mm and ground to a finish of 10 μm with 400 grit paper. The tests were carried out in an automated test rig with adjustable temperature, blade tip velocity, and incursion rate. The rig is configured such that the coatings are exposed to rotating blades, making contact with the tips as they pass. In this study, investigators monitored the number of contacts, removing and examining abraded coating samples at a given count total ranging from 200 to 4000. It was found that wear characteristics change with each contact between the coating and blade tip, indicating that pass number is a factor that must be considered when testing abradable coatings.

Agglomerated and sintered Cr 3 C 2 -25%NiCr powders possess excellent flow ability and appearance that have been extensively applied to resist abrase and erosion in high temperature applications such as power boiler and turbine blade. Microstructure of Cr 3 C 2 -25%NiCr coatings were observed through scanning electronic microscope (SEM), and bond strength and microhardness of coatings were measured by tensile shearing test and Vickers hardness test. It is indicated that ultrafine Cr 3 C 2 -25%NiCr coatings have some outstanding properties to traditional Cr 3 C 2 - 25%NiCr coatings by plasma sprayed.

The current situations of thermal spraying materials in China are described in this paper. The thermal spraying technology in China has a great progress over tens of years. More than one hundred varieties of material products are serving in thermal spraying industry now, which are grouped into three kinds: powders, wires and rods. And technologies for producing alloy or ceramic or composite powders, alloy or cored wires, and oxide ceramic rods are applied to large-scale production. Many research and development works on advanced materials for thermal spraying are carrying out in recent years. They show that the general tendencies of thermal spraying materials in China are composite or low-impurity component, ultrafine or nanosized microstructure, high properties, as well as specialized and systematized applications. Thermal spraying materials have great prospects in China.

Plasma sprayed chromium oxides coatings have been widely applied in anilox rolls and pump seal for many years. This paper is researching the effect of nanostructured Cr 2 O 3 5SiO 2 3TiO 2 composite powder preparation when adding nano-size SiO 2 and TiO 2 powder in Cr 2 O 3 powder, to prepare for through spray drying, high temperature sintering and flame density. The microstructure of powder and plasma sprayed coating are analyzed by SEM and XRD, compared with pure Cr 2 O 3 powder and METCO 136F powder. The Microhardness of the coatings are measured by 402MVA TM Vickers hardness tester. Fracture test is used to analysis the ductility of coatings, and the fracture appearance is analyzed by SEM. The result indicates that the mechanical behaviors of nanostructured Cr 2 O 3 5SiO 2 3TiO 2 coating has better performance in the nature of hardness and ductility.

In this paper, nanostructure Lanthanum zirconate thermal barrier coatings (MCrAlY+ La 2 Zr 2 O 7 ) were prepared by atmospheric plasma sprayed (APS). The microstructures and thermal stability properties were systematically studied by Scanning Electric Microscopy (SEM), transmission electron microscope (TEM) and X-Ray diffraction(XRD). The results showed that the nanostructured lanthanum zirconate coatings were typical lamellar structure which was composed of columnar grains about 90nm in diameter. A large quantity of micro-cracks and homogeneous distributed fine pores formed in the nanostructured zirconia coating. After ablation at 1300 °C for 24 h, no apparent phase transformation was observed in lanthanum zirconate coating. The growth mechanism of the grains was subsequently discussed.

Chromium oxide coatings are used in gas turbine engines in anti-wear applications. Ultrafine YPSZ and WC/Co feedstock powders have already been widely used to prepare the ultrafine structured YPSZ and WC/Co coatings, which exhibited improved mechanical properties when compared to those of conventional coatings. Ultrafine chromium oxide powders, prepared by the method of solution precipitation, can not be directly used as plasma spray feedstock powder, because of its low mass of individual ultrafine particle and not good flowability. In this paper, spray drying and heat treatment are used to reprocess the ultrafine chromium oxide powder. The chromium oxide coating is prepared by plasma spraying. X-ray diffraction (XRD) is used to analyze the phase constituents of the feedstock powder and coatings. Scanning electron microscopy (SEM) is used to observe the morphology and particle size of ultrafine powder feedstock powder as well as to examine the microstructure of the chromium oxide coating. In addition, loose density and flowability of the feedstock powder and hardness and bond strength of the ultrafine chromium oxide coating are measured. Experimental results show that the large agglomerated ultrafine chromium oxide feedstock powder after being reprocessed are spherical, have good flowability and high loose density, which are suitable for plasma spraying. The wear properties and microstructure of the ultrafine chromium oxide coatings are improved when compared to the ones of the conventional coatings.