ZrOCl 2 •8H 2 O and NH 4 OH were regarded as original materials to prepare zirconia sol by co-precipitation, and nano-zirconia coatings were prepared by sol plasma spraying. The structure of the coatings was analyzed by SEM, XRD, and influence of power and stabilizer, concentration and dispersed phase on the coatings was investigated primarily. The result showed that the sol was non-crystal structure after spontaneously dried, the coatings were mixed of nanostructure of monoclinic and cubic phase after plasma jet heated. Increasing power decreased the content of non-crystal phase, adulterating yttria had good crystal phase stabilization, and the content of monoclinic phase decreased greatly. Coatings were denser when higher concentration and ethanol qua dispersed phase were used. Porosity of coatings decreased prior and increased later along with concentration increasing.

Supersonic plasma spraying has been used to deposit WC-12Co coatings on polished stainless steel and aluminum substrate surface. The microstructure was observed by SEM and the bond mechanism was analyzed. It can be seen that individual WC particles can embed the substrate and make the substrate surface rough. The substrate materials differ, the depth that WC embed is also different. Bond among coatings mainly belonged to mechanical bonding. Bond between coatings and substrate mainly belonged to mechanical bonding, and partially belonged to metallurgy bonding, physical bonding, diffusion and micro-forging.

TiN coatings and some particle of TiN were prepared by reactive plasma spraying, in which titanium powder react with nitrogen under different flow rate, at the same time keeping all other parameters invariableness. The microstructure of the TiN coatings and particles were analyzed by means of SEM and the rate of TiN coating was tested by XRD. The results show that the microstructure and transformation rate of TiN coatings are greatly affected by nitrogen flow rate. The microstructure and transformation rate of TiN coatings were the best when the nitrogen flow rate was 1500 L/h.

The influence of spray parameters on particle with the improved plasma gun was studied by using SpryWatch-2i System. The results show that the particle velocity increases and exceeds the velocity of sound when using a new designed nozzle (C2 nozzle) during the plasma spraying. Under a certain condition, the particle velocity varies as the spray distance rise firstly, decline then, as the primary gas pressure increases, the particle velocity increases, the particle temperature drops firstly then increase, the velocity increase a little. But as the steadily increase of the flow rate, the influence on the particle temperature drops, the influence of arc voltage on particle velocity and temperature is slightly. Arc current influent little on particle temperature, but the particle velocity increase in a range.

The goal of this study is to find applicable spray conditions for producing tungsten (W), zirconium carbide (ZrC), and W-ZrC cermet layers. In the experiments, W and ZrC powder mixtures were fed into the plasma of a water-stabilized plasma gun and coatings approximately 1 mm thick were sprayed on graphite substrates. Pure W and pure ZrC were deposited under similar conditions. Microhardness, surface roughness, XRD, XRF, dilatometry, and spectroscopic techniques were used to characterize the coatings. The resulting coatings were found to be hard with a high elastic modulus.

The plasma torch is one of the most important equipment during air plasma spraying, is used to produce the plasma arc in the nozzle for the acceleration and heating of particles. The voltage-current characteristic of the plasma arc is very important to the fusion of particles. The volt-ampere characteristic is affected by many factors, such as gas species, gas flow rate, nozzle geometry and the type of gas injection. So the factors influencing the voltage-current characteristics in high velocity plasma spraying were studied. As the results showed, the arc voltage is increased with the increase of the primary gas flow rate in some range. The secondary gas flow rate has an important effect on the electric arc voltage. The influence of nitrogen on the arc voltage is more than argon when they are chose as the primary gas in plasma spraying. The arc voltage is decreased with the increase of the nozzle’s compression angle and the decrease of the nozzle’s aperture, when the length of the nozzle is unvarying.

The jet characteristics of supersonic plasma jet spraying (SPJS) system were studied. Comparison of jet property was made between conventional plasma spray system and SPJS system. The results showed that the characteristics of the SPJS system are superior to the latter system. The particles velocities in the range of 400~800 m/s are obtained for supersonic plasma jet guns with 4.5 mm diameter nozzles and 60 l /min total gas flow rates, SPJS operate about 36 KW. The particle velocity is more than two times as much as conventional plasma jet spraying. The supersonic plasma jet is much longer than that of the conventional torch. It can bring about improvement for flying powder heated and accelerated and also prolong spray distance.

The adhesive strength between substrate and sprayed coatings seems to be mainly due to the mechanical interlocking effect. The physical bonding of spray particles to the substrate is the second factor. In this paper, the bonding mechanisms of sprayed coatings were studied on basis of experiments with the substrate at different surface roughness. The substrate surface roughness was quantitatively evaluated using a surface roughness tester. The tensile adhesion strength test method was used to evaluate the adhesive properties. The relationship between surface roughness and adhesive strength was investigated. The adhesive strength of plasma sprayed coating decreased with an increase in substrate surface roughness, as the size of the grit particles for roughening increased. On the contrary, the adhesive strength of arc sprayed coating increased.

The physical bonding of spray particles to the substrate is a main factor which contributes to the high adhesive strength of HVOF WC-Co coatings in addition to the mechanical interlocking effect. The adhesive strength between substrate and coatings deposited with partially melted particles under HVOF spray conditions has a significant contribution from physical bonding compared with conventional thermal spray processes having molten particles with relatively low velocity. The physical bonding results from the high impact velocity of partially-molten droplets during the HVOF spraying process.

This paper describes an initial development of oxidation resistant coatings for SOFC (solid oxide fuel cell) interconnectors using LaSrCoFe oxide (LSCF, (La 0.6 Sr 0.4 )(Fe 0.8 Co 0.2 )O 3 ). The process involved the development of hermetic coatings using a HVOF (high velocity oxy-fuel) spray process, specifically a θ-gun spray process. The X-ray diffraction of the powder and the coating is analyzed at first. To get the hermetic coating, numerous process parameters were chosen using design of experiments (DOE). The hermeticity of the coating was tested using a salt spray test. After these tests, a hermetic LSCF coatings was obtained with virtually no interconnecting pores.

As DRAM technology extends into 12-inch diameter wafer processing, plasma-induced wafer charging is a serious problem in DRAM volume manufacture. There are currently no comprehensive reports on the potential impact of plasma damage on high density DRAM reliability. In this paper, the possible effects of floating potential at the source/drain junction of cell transistor during high-field charge injection are reported, and regarded as high-priority issues to further understand charging damage during the metal pad etching. The degradation of block edge dynamic retention time during high temperature stress, not consistent with typical reliability degradation model, is analyzed. Additionally, in order to meet the satisfactory reliability level in volume manufacture of high density DRAM technology, the paper provides the guidelines with respect to plasma damage. Unlike conventional model as gate antenna effect, the cell junction damage by the exposure of dummy BL pad to plasma, was revealed as root cause.

Thick Nanostructured PSZ- NiCoCrAlY graded TBCs were got by air plasma spraying. The results reveal the morphology and phase transformation of TBCs by means of SEM and XRD. The plasma spray process results in a characteristic layered structure consisting of lamellae, unmelted nano-particles and an inter-lamellar porosity. The test results of thermal shock show that the graded coatings have different failure behavior, which caused by thermal stress, radial cracks penetrating and substrate oxidation. The failure mode was the spallation of top coat due to thermal stress. The improved strain tolerance of the top coat was benefited from the high coating porosity, the segmentation cracking, the fine-splat size and the unmelted nanoparticles. It has been found that the lamella consists of nanoscale columnar grains parallel to the spraying direction.

This paper will demonstrate a new copper (Cu) electroplating technique [1] for accurately isolating high resistance fault locations with resistance below K-order ohms. This phenomenon is achieved by having different electric field intensity leading to different copper deposition rate on the sample surface. From experiments, the interface between the thicker electroplated and thinner electroplated copper layer on the sample surface accurately indicates the high resistance fault location. Also, Optical Microscope (OM) and Focused Ion Beam (FIB) are used to inspect the localized fault site of the electroplated sample. Furthermore, this technique, Electro-Plating Localization Method (EPLM), can process several samples or the entire wafer at the same time. In addition, this technique can be applied in the fully open cases of test vehicles with logical circuit as voltage contrast localization method.

By use of homemade arc spraying system patented, which could make melted metal droplets atomized fully and make its flying velocity achieve ultrasonic velocity, TiAl alloy coatings were manufactured on the aluminum alloy (LY12) substrate surface. The slide wear resistance of TiAl alloy coatings was investigated. The effect of spraying parameters, coatings' chemical composition and microstructure on the slide-wear resistance of coatings was examined. Then the slide-wear mechanism of the coatings was discussed. The results showed that the slide wear resistance of TiAl alloy coatings by ultrasonic arc sprayed is 17 times higher than it of the aluminum alloy (LY12) substrate under the condition of dry slide-wear.

The paper presents the basic principle and application of High Velocity Arc Spraying technique. Through adopting convergent-divergent nozzle, air circulation cooling and computer aided design technique, particle velocity was enhanced, which surpasses velocity of sound, and atomization effect was improved, so HVAS fabricated high quality coating. Experiment results show that HVAS has high particle velocity, high atomization effect, high bond strength and low porosity. Average velocity of atomized Aluminum particle is 373m/s. Bond strength, porosity and average particle size of 3Cr13 coating are 60MPa, 0.9% and 4.32 m respectively. For high coating quality, HVAS is widely used in maintenance, corrosion resistance and surface strengthening.

Thermal spraying technique has been widely applied for the production of ceramic protection layer on metals that used in various hostile environments. However, all sprayed coatings have defects such as connected pores and unmelted particles, which deteriorate coating properties. To improve the properties of sprayed coatings, a lot of approaches have been undertaken such as laser irradiation, seal sintering with liquid alloys and sol-gel infiltration technique. Lasers are promising technological tools due to its speedy treatment and simplicity of process control. Moreover, laser treatment technology enables not only the post-treatment but also the pre and simultaneous treatment by combining with spraying process. Generally, wide beams of as uniform as possible are preferred for use in laser surface treatment to obtain a uniform depth of melting, alloying or cladding and to cover a large area by partially overlapping of tracks. However, it is not easy to produce a uniformly treated coating by conventional laser treatment method as desired. To obtain a near-uniform beam intensity for practical laser irradiation, a kaleidoscope was installed in a conventional YAG laser. In this research, laser beam properties of YAG laser equipped with a kaleidoscope and its effect on surface modification of plasma sprayed zirconia coatings and WC-Co system coatings prepared by HVOF spraying was investigated.

By means of homemade ultrasonic arc spraying equipment patented, under the condition of the optimum arc spraying parameters, TiAl alloy coatings were manufactured on the aluminum alloy (LY12) matrix surface. The ultrasonic arc spraying forming process and microstructure of TiAl compounds alloy coatings were investigated by the color metallurgical microscopy, SEM, XRD, EPMA and chemical composition quantitative analysis (ICP). The results showed that TiAl compounds composite coatings can be synthesized by ultrasonic arc spraying system, the coatings possess typical lamella character, consist of TiN (or TiO), TiAl, Ti 0.7.1.1 Al(N,O), Ti 2.4 Al(N,O), Ti 2.4 Al and aluminum alloy solid solution.