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In this work, the reactive magnetron co-sputtering with oblique angle deposition (OAD) was used for preparing NiWO nanorod films. The influence of the sputtering power of Ni target on the microstructural, morphology, and chemical composition of the NiWO nanorod films were investigated. The grazing incident X-ray diffraction (GIXRD) pattern indicated that all prepared nanorod films show amorphous. From the field-emission scanning electron microscope (FE-SEM), the prepared films are in the shape of the slant nanorods with well-separated nanocomlumnar. The effect of Ni-sputtering power on the diameter, length, and tilt angle of the prepared nanorods was discussed based on the shadowing effect and adatom energy. The atomic force microscopy (AFM) shows that the surface roughness increased with increasing the Ni-sputtering power. In addition, the chemical state and composition of Ni, W, and O were determined by X-ray photoelectron spectroscopy (XPS) and discussed in this paper.

The purpose of this paper is to develop both an AC signal generator and a dual-channel oscilloscope based on standard personal computer equipped with sound card as parts of the laboratory of the fundamental physics and the introduction to electronics classes. The setup turns the computer into the two channel measured device which can provides sample rate, simultaneous sampling, frequency range, filters and others essential capabilities required to perform amplitude, phase and frequency measurements of AC signal. The AC signal also generate from the same computer sound card output simultaneously in any waveform such as sine, square, triangle, saw-toothed pulsed, swept sine and white noise etc. These can convert an inexpensive PC sound card into powerful device, which allows the students to measure physical phenomena with their own PCs either at home or at university attendance. A graphic user interface software was developed for control and analysis, including facilities for data recording, signal processing and real time measurement display. The result is expanded utility of self-learning for the students in the field of electronics both AC and DC circuits, including the sound and vibration experiments.

HT-6M will be officially installed in Thailand in next few years. Some computational studies of possible experiments should be helpful in case of its experiment planning. The authors are interested on the scenario of macro-particle, i.e. dust and droplet, transporting in HT-6M. The study was carried out by the Dust and Droplet Tracking (DDT) code, consisting of basic equations and physical models involving with charging, heating, equation of motion and ablation on macro-particle in a tokamak plasma. DDT implemented a set of HT-6M core plasma profiles from the Transport Analyzing System for tokamaK (TASK) code and a set of HT-6M edge plasma profiles approximated from simple SOL model. We observed that relatively small macro-particles, i.e. initial sizes are less than 10−6 m, significantly involve with impurity generation near plasma facing components (PFCs). In addition, the 10−5-m macro-particles mostly ablate in SOL. The 10−3-m and 10−4-m macro-particles completely ablate if they transport towards core plasma, but some with the inclination with respect to the horizontal direction obtain longer lifetimes. Moreover, few of them can achieve abnormal high speed. The mechanism for this is the acceleration by rocket force due to partial ablation near core plasma.

To characterize magnetic materials on nanoscales, a new technique has been developed which is based on the combination of two scanning thermal near-field techniques: the thermally modulated ferromagnetic resonance induced by the probe of a scanning thermal wave microscope and the detection of the 3ω signal from the same thermal probe. The simultaneous detection of the thermally modulated microwave absorption and of the 3ω response of the nanoprobe offers a means to control the thermal contact between probe and sample during scans across the sample. In this contribution, the experimental setup is described and results of measurements conducted on Fe-based structures deposited on a MgO substrate are presented.

In most metal matrix composites (MMCs) interfaces are decisive but hard to manipulate. Especially copper–carbon composites can exhibit excellent mechanical and thermal properties only if the Cu/C interface is modified by an optimised interlayer. Due to the excellent thermal conductivity and mechanical stability of diamond this form of carbon is preferred as reinforcement in heat sink materials (copper–diamond composite) which are often subjected to severe thermal and mechanical loads. In the present case niobium and boron interlayers of various thicknesses were deposited on diamond and vitreous carbon substrates by magnetron sputter deposition. After the coverage of all samples by a copper film, a part of the samples was subjected to heat treatment for 30 min at 800 °C under high vacuum (HV) to simulate the thermal conditions during the production of the composite material by uniaxial hot pressing. De-wetting during heat treatment leads to the formation of holes or humps in the Cu coating. This effect was investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). A comparison of time-of-flight secondary ion mass spectroscopy (TOF SIMS) profiles of heat treated samples with those of as deposited ones showed the influence of interdiffusion during the heating process. Diffusion behaviour and chemical composition of the interface were also studied by cross sectional transmission electron microscopy (X-TEM) investigations using focused ion beam (FIB) cut samples. The thermal contact resistance (TCR) of the interface was calculated from results obtained from modulated infrared radiometry (IR). Thin interlayers suppressed de-wetting most effectively and consequently the TCR at the Cu–diamond interface was found to decrease. Therefore they are promising candidates for optimising the Cu–diamond interface., Highlights ► The interface in the Cu–C system was modified by boron and niobium interlayers. ► Thermal treatment of the samples simulated the production process of Cu–diamond MMCs. ► The TCR of the interface was investigated by modulated infrared radiometry. ► Chemical- and diffusion processes were investigated by TEM of interlayer cross sections. ► Very thin interlayers improve the mechanical and thermal interfaces.

Modulated IR radiometry, which is usually applied to sputter-deposited thin films and coatings, to determine the thermal transport properties of the thin films, is applied in this work to analyze the effects of different substrate materials and the effects of the interface coating-substrate on the resulting multi-layer system. For this purpose, a small number of ZrN films of different thickness were deposited on different substrate materials (stainless steel, Si, and glass) and were analyzed with the help of modulated IR radiometry, using heating modulation frequencies in the range from 1 Hz to 100 kHz, allowing depth-resolved thermal measurement from the sub-micron range to the millimeter range. The effects of pre-treatment of the substrates and of the interface between thin films and substrate were also analyzed. Compositional and structural properties of the thin films were obtained by RBS, XRD, and SEM. Preliminary results on the effects of substrates of limited thickness and three-dimensional heat transport, at the transition from coatings of good thermal transport properties to substrates of low thermal transport properties, are reported. A biasing effect related to the deposition process was also identified.

The manipulation of mechanical and thermal interfaces is essential for the design of modern composites. Amongst these are copper carbon composites which can exhibit excellent heat conductivities if the Cu/C interface is affected by a suitable interlayer to minimize the Thermal Contact Resistance (TCR) and to maximize the adhesion strength between Cu and C. In this paper we report on the effect of boron based interlayers on wetting, mechanical adhesion and on the TCR of Cu coatings deposited on glassy carbon substrates by magnetron sputtering. The interlayers were 5 nm thick and consisted of pure B and B with additions of the carbide forming metals Mo, Ti and Cr in the range of 5 at.% relative to B. The interlayers were deposited by RF magnetron sputtering from either a pure B target or from a composite target. The interlayer composition was checked by Auger Electron Spectroscopy and found to be homogenous within the whole film. The system C-substrate/interlayer/Cu coating was characterized in as deposited samples and samples heat treated for 30 min at 800 °C under High Vacuum (HV), which mimics typical hot pressing parameters during composite formation. Material transport during heat treatment was investigated by Secondary Ion Mass Spectroscopy (SIMS). The de-wetting and hole formation in the Cu coating upon heat treatment were studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The adhesion of the Cu coating was evaluated by mechanical pull-off testing. The TCR was assessed by infrared photothermal radiometry (PTR). A correlation between the adhesion strength and the value of the TCR which was measured by PTR was determined for as deposited as well as for heat treated samples., Research Highlights ► Investigation of thermomechanical properties of carbon/metal interfaces. ► Application of infrared photothermal radiometry (PTR) for layered media. ► Correlation of mechanical and thermal properties for carbon/metal interfaces.

The influence of defective areas in the interface on the correlation between the thermal interface conductance and the mechanical adhesion strength was investigated on as-prepared and heat-treated samples of copper-coated carbon flat specimens with different bonding layers between the copper film and the substrate. The thermal interface conductance was determined by frequency-domain photothermal radiometry. The mechanical adhesion strength of the film coating was deduced from pull-off experiments. The imperfect interfaces were modeled by two different values for the thermal interface conductance, $$G_{1}$$ and $$G_{2}$$ , which co-exist at different areas on the interface and are weighted according to their areas, $$A_{1}$$ and $$A_{2}$$ . The model parameters were determined by adjusting the frequency dependence of the normalized phases and phase differences of the PTR signals from as-prepared and heat-treated samples. The total thermal conductance of the interface was found to exhibit a correlation with the adhesion strength for most of the heat-treated samples whereas, among the as-prepared samples, considerable deviations from such a trend exist. The observations are explained by the impact of supplementary stress on the adhesion strength measurements which are due to the strain developed during the preparation process at the interface. The interfacial stress and strain are mostly released during thermal annealing. A semi-empirical formula was developed that describes the impact of the defective areas on the adhesion strength using the experimentally determined thermal model parameters.

The purpose of this study is to estimate thermal diffusivities of high thermal diffusivity bulk material as well as low thermal diffusivity bulk material by using many types of fluid such as Ethyl alcohol and water. This method is studied by measuring amplitude and phase of photodeflection signal in various frequency modulations. The experimental setup consists of two laser lines: 1) a pump laser beams through a modulator, varied frequency, controlled by lock-in amplifier and focused on sample surface by lens. 2) a probe laser which parallels with the sample surface and is perpendicular to the pump laser beam. The probe laser deflection signal is obtained by a position sensor which controlled by lock-in amplifier. Thermal diffusivity is calculated by measuring the amplitude and phase of the photodeflection signal and compared with the thermal diffusivity of a standard value. The thermal diffusivity of SGG agrees well with the literature but the thermal diffusivity of Cu is less than the literature value by a factor of ten. The experiment requires further improvement to measure the thermal diffusivity of Cu. However, we succeed in using ethyl alcohol as the coupling medium instead of CCl4 which is highly toxic.

The purpose of this paper is to develop a digital lock-in amplifier based on soundcard interface for undergraduate physics laboratory. Both series and parallel RLC circuit laboratory are tested because of its well-known, easy to understand and simple confirm. The sinusoidal signal at the frequency of 10 Hz – 15 kHz is generated to the circuits. The amplitude and phase of the voltage drop across the resistor, R are measured in 10 step decade. The signals from soundcard interface and lock-in amplifier are compared. The results give a good correlation. It indicates that the design digital lock-in amplifier is promising for undergraduate physic laboratory.

In this study, the heat transport in copper–carbon flat model systems was studied by frequency-dependent photothermal radiometry (PTR). The samples consist of Cu films of about 1 μm thickness deposited by magnetron sputtering on vitreous carbon (Sigradur). Particular interest was devoted to the influence of interface defects on the interfacial thermal conductance (or resistance) of the CuC systems. The PTR data were analyzed in the frame of a heat diffusion equation for one- and three-dimensional heat transport. By comparing PTR signals from as-prepared and from heat-treated samples, the lateral inhomogeneities of the interfacial thermal conductance could be quantified. The measured phase differences were analyzed in the scope of a model where a small part of the surface area has a different interfacial thermal conductance than the major part of the surface.

Multifunctional coatings consisting of transition metal oxycarbides and oxynitrides deposited by physical vapour deposition techniques on tool steel are analysed in this work by means of modulated IR radiometry (MIRR), a non-contact non-destructive thermal wave measurement technique, with respect to the thermal transport properties relevant for time-dependent surface heating processes of coating–substrate systems. In order to interpret the measured data quantitatively, an inverse solution of the two-layer thermal wave problem is applied, which relies on the thermal wave phase lag data measured as a function of modulation frequency of the periodically modulated laser beam heating intensity. Based on these measurements and their quantitative interpretation, correlations between the thermal transport properties of the coatings and their deposition conditions have been found, which can be used to monitor deposition processes. For a second objective of this work, namely to determine the film thickness by means of MIRR, different sets of thin films of approximately constant thermal transport properties, but differing film thickness, have been measured. To discuss the limitations and error limits of these non-contact non-destructive measurements of the coating thickness, the results obtained by MIRR are compared with the coating thickness determined by destructive measurements.

The thickness of coatings can be determined using the data measured by Modulated IR Radiometry for sets of coatings, produced under specific controlled conditions: – Keeping constant all deposition parameters except the deposition time, coatings of approximately constant thermal transport properties, but different thickness are produced. The modulated IR phase lag signals measured for the coatings are calibrated with the help of signals obtained for homogeneous opaque reference samples of smooth surface. Quantitative results for the thermal transport properties are obtained using the inverse solution of the 2-layer thermal wave problem by which direct relations are established between the relative extrema of the inverse calibrated thermal wave phase signals measured as a function of the heating modulation frequency and the thermal coating parameters, the ratio of the effusivities coating-to-substrate, the coating's thermal diffusion time, and the coating thickness. The coating thickness values obtained by Modulated IR Radiometry are compared with the values measured by standard microscopic methods, and relative errors of 3 – 4% have been found for the coating thickness of a set of TiCO coatings on steel, presented here as an example.