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This paper focused a two-step procedure to imprint the tailored emblems, patterns, symbols and codes onto the metallic and polymer product surfaces. The laser printing was first used to form these tailored micro-/nano-textures onto a Diamond-Like Carbon (DLC) coating die. The DLC film with the thickness of 20 mm and the hardness of 22 GPa was utilized as a mother die. Femtosecond laser printing was used to shape the tailored micro-/nano-textures on this die. Seven emblems such as a star-patterned texture with the maximum depth of 4 mm were just cut into the DLC-die to have color-grating by micro-texturing and surface plasmonic brilliance by nanotexturing. In second, Computer Numerical Control (CNC) – stamping was used to imprint these textures onto the aluminum alloy plate with the thickness of 1 mm. Scanning Electron Microscopy (SEM) and three dimensional profilometer were used to investigate the geometric accuracy in this two-step printing procedure. The constituent micro-/nano-textures of each emblem was accurately imprinted onto the aluminum work. The optical properties were also duplicated together with this geometric imprinting.

The plasma nitriding conditions and processing parameters were controlled to attain the high-density nitrogen ion and NH-radical populations and to form the nitrogen supersaturated layer into AISI420 type martensitic stainless steel mold substrate at 673 K for 14.4 ks and 28.8 ks. Thicker nitrided layer than 80 mm was attained for fine machining of the optical diffraction elements onto this nitrided AISI420 mold surface. The average hardness in this nitrogen supersaturated layer reached 1400 HV. After this hardness testing and microstructure analysis, the machinability test was performed to describe the ductile mode cutting behavior of nitrogen-supersaturated work by using the PCD (Poly-Crystalline Diamond)-chip tool. Higher average nitrogen solute content than 4 mass% was responsible for fine turning by PCD-chip and CVD (Chemical Vapor Deposition)-diamond coated cutting tools without any damages and for precisely finishing the mold surface with the lower maximum surface roughness than 10 nm on the machined mold surface. The low roughness and homogeneous machined surface profile proved that the nitrogen supersaturated AISI420 series stainless steel was adaptive as a stamping mold of chalcogenide glasses with high dimensional accuracy and demolding capacity.

The carbon supersaturated SKD11 punch and core-die were prepared by the plasma carburizing at 673 K for 14.4 ks. The upsetting experiment was performed by using this punch to describe the plastic flow of pure titanium and β-titanium works in higher reduction of thickness than 50%. The measured load – stroke relationship was utilized to describe the frictional behavior on the contact interface of punch to work materials and their work hardening process. The contact interface of carbon supersaturated punch to work was analyzed to investigate the formation of isolated carbon tribofilms from punch material and to describe the in situ solid lubrication on the contact interface. The micro-hardness mapping technique was also utilized to investigate how to suppress the work-hardening behavior by this in-situ solid lubrication. Free near-net forging experiments were performed to shape the circular β-titanium alloy wires to triangular bars.

A pair of punch and die was often fabricated using subtractive manufacturing processes such as milling and other machining processes. However, additive manufacturing could be used to perform the same processes. This study explored this possibility. In particular, this study fabricated a pair of T-shaped punch and die made of AISI316L austenitic stainless steel using an additive manufacturing process called plasma-assisted 3D printing. Accordingly, T-shaped negative and positive 2D patterns were screen-printed onto the mirror-polished surfaces of the substrates made of AISI316L austenitic stainless steel. The printed film worked like a mask to prevent the printed substrate surfaces from nitriding. In order to form a thick nitrided layer, the unprinted substrate surfaces were selectively nitrided at 673 K for 14.4 ks. The un-nitrided segments of the substrates were uniformly removed by sand-blasting that involved shooting silica particles on the substrate’s surfaces. As a result, the substrates printed with negative and positive T-shaped patterns were transformed into the punch head and die cavity. In order to see the efficacy of the fabricated punch and die pair, this pair was used for piercing the electrical steel sheets under a controlled clearance. Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX) was used to measure surface topography after piercing. In addition, SEM and a 3D profilometer were used to measure the punch and die profiles after piercing. The abovementioned measurement results showed that the fabricated punch and die exhibited highly accurate piercing behavior. Thus, the plasma-assisted 3D printing was useful for punch and die fabrication.

The dry progressive stamping was strongly required to make mass production of clothing parts and beverage cans. The duplex coating was one of the most reliable means to protect the dies and punches from wear and friction and to prolong their life time. In this coating, the die and punch was first surface-treated to have sufficient hardness in compatible to the hard ceramic coatings. In the present study, the low temperature plasma nitriding at 673 K was employed to harden the six kinds of punches and dies for progressive stamping of copper alloyed fucks. The micro-structure and nitrogen mapping were investigated by SEM with EDS to demonstrate that the hardening took place by nitrogen super saturation into SKD11 matrix without nitride precipitations. These nitrogen super-saturated punches and dies were fix into the progressive die set for dry stamping. No significant wear of tools as well as reduction of stamping loads even after a million shots proved that the low temperature plasma nitriding should be suitable to make hardening of dry stamping die substrates even without use of hard ceramic coatings.

This paper concerned with micro-embossing of micro-cavities and micro-grooves into aluminum sheets by CNC-stamping with use of the arrayed DLC multi-punches. Both SKD11 and AISI420 steel die substrates were prepared and DLC-coated with the thickness of 10 to 15 μm. This DLC coating worked as a punch material. The two dimensional micro-patterns were printed onto this DLC film by maskless lithography. The unprinted DLC films were removed by the plasma oxidation to leave the three dimensional DLC-punch array on the steel substrate. This micro-pillared and micro-grooved DLC-punches were placed into the cassette die set for micro-embossing process by using the table-top CNC stamper. The micro-circular patterns transformed to the micro-pillars in the DLC punch by the plasma oxidation. Through the CNC-micro-embossing, this micro-texture further transferred to micro-cavities in the aluminum sheet. The dimensional accuracy of embossed micro-textures by stamping was measured by SEM and three dimensional profilometer with comparison to the tailored micro-pattern and the DLC-punch array configuration.

The plasma printing was developed as a means to fabricate the micronozzle chip with the inner diameter less than 50 μm. The initial two-dimensional micropattern was printed onto the stainless steel substrate surface by the maskless lithography. These printed micropatterns were utilized as a mask to make selective nitriding into the unprinted surface. After removal of printed pattern, the un-nitrided surfaces were chemically etched to leave the nitrided microtexture as a micronozzle chip. High nitrogen supersaturation as well as selective nitrogen diffusion had influence on the spatial resolution in this plasma printing in addition to the digitizing error in the maskless lithography.

Hollow-cathode oxygen plasma etching was proposed as a promising means to make micro-texturing into CVD diamond coatings. Oxygen ions and electrons were confined in the hollow-cathode to have higher ion and electron densities in the order of 1017 to 1018 m−3 in the inside of hollow-cathode. Quantitative plasma diagnosis proved that direct reaction of oxygen atom or radicals with carbon in the diamond coating should drive the reactive ion etching (RIE) process. A diamond-coated WC (Co) disc specimen was employed to describe the RIE-behavior with aid of stainless steel mask with the line width of 100 μm. Surface depth profile measurement as well as the Raman spectroscopy demonstrated that a micro-groove was precisely etched into the diamond film as a sharp-edged profile.

The plasma oxidation printing (POP) was proposed as a digital manufacturing to shape the diamond-like carbon (DLC) thick film into a micronozzle on the tool steel substrate. Its head shape was first designed by computer-aided design (CAD) and printed onto DLC film by the maskless lithography. The unprinted DLC was removed in depth by the anisotropic etching. Fine circular nozzle with the inner diameter of 10 μm and the height of 10 μm was fabricated during the duration time of 3.6 ks. Different from the micromilling or the micro-electric discharging, the micronozzle geometry is directly fabricated from its CAD data. The micronozzle with the cross-star outlet was constructed without the change of processing procedure and without use of tooling.

The initial microdot and microline patterns were first ink-jet printed onto the surface of polished AISI420 stainless steel mold. This masked mold substrate was nitrided at 693 K for 7.2 ks at 70 Pa by using the high-density plasma nitriding system. The unmasked parts were selectively nitrided to have higher hardness than 1200 HV. This hardness-profiled substrate was mechanically sand-blasted to fabricate the microtextured mold. Microdisk patterned plastic cover-case for cellular phones were injection-molded by using this method for practical demonstration. Both the selective hardening and anisotropic inner nitriding processes were experimentally discussed as a key step in the present processing.

Mass production of heat radiation devices requires for fine stamping of micro-textured patterns in the order of micro-meters in dimension onto the sheet product. In this duplication of micro-textured patterns, an original mother micro-pattern in the convex type has to be transferred onto the metallic sheet in the concave type with sufficient accuracy. The authors have proposed a micro texturing of original micro patterns onto the DLC coated mother die-and mold-unit. Once this unit is inserted and fixed in the stiff cassette die-set, the CNC-controlled stamping system works well for progressive stamping process to duplicate the original micro-patterns onto aluminum sheet. In the present paper, two kinds of motion in the stamper were designed to investigate the effect of loading and unloading sequences on the geometric accuracy in micro-texturing. Both the macroscopic and microscopic plastic deformations were described by SEM observation. First, high density oxygen plasma etching method was introduced to explain how to fabricate the micro-textured DLC-die unit. The constant-load motion control was employed as a normal motion in CNC-stamping to describe the microscopic metal flow by piercing the DLC micro-punch into the aluminum sheet. Deep micro-cavities with 3.5x3.5x3 μm3were successfully formed by application of high pressure in stamping. The pulse-wise motion control was further used to improve the geometric accuracy in the present duplication of original micro-texturing pattern onto the aluminum sheet. Owing to the incremental loading in this motion control, the micro-friction was significantly reduced to activate the microscopic metal flow in formation of micro-cavities.

Diamond-like carbon (DLC) coatings have been utilized as a protective tribo-coating of punches and dies to decrease friction in forming processes. Although their frictional performance is characterized by ball-on-disc or pin-on-disc methods, their practical endurance behavior must be evaluated by metal forming simulators with consideration of wear severities in each individual forming process. Both Si-doped and nano-laminated DLC coatings were employed to perform an engineering characterization of their durability and toughness in practical metal forming operations and to search for new directions for DLC coating technology development to prolong tool life.

Diamond like carbon (DLC) coated tools have been widely utilized in the dry milling and cutting of aluminum alloy parts and components. Since the DLC film deteriorates during milling operations by reduction of the film thickness or adhesive wear, it must be removed or ashed away before grinding, polishing and recoating not only to preserve high quality of the machined products but also to reduce the production cost. In the present paper, high density oxygen plasma ashing was applied for the complete removal of the used DLC coating together with the chromium interlayers without damaging the tool substrate materials. DLC-coated end-milling tools were prepared to prove that the whole DLC coating could be completely removed at a faster rate than by conventional approaches.

Electrical beam (EB) irradiation is used to chemically modify the amorphous carbon film, a-C:H, which is prepared by the DC magnetron sputtering. The starting a-C:H film has vague columnar structure with lower density intercolumns as predicted by Thornton structure model. The EB-irradiated a-C:H film has fine nano-columnar structure with the average columnar size of 10–15 nm. This size is equivalent to the measured in-plain correlation length by the Raman spectroscopy. Little change in the sp2/sp3 bonding ratio is observed in the columnar matrix before and after EB-irradiation. Increase of sp2/sp3 ratio is noted in the intercolumns of irradiated a-C:H films. No change is detected in the hydrogen content of a-C:H films before and after EB-irradiation: 35 at% hydrogen in a-C:H. Increase of the in-plain density via EB-irradiation, is attributed to the increase of local atomic density in the intercolumns, which is measured by the electron energy zero-loss spectroscopy. This local densification is accompanied with ordering or graphitization in the intercolumns of the EB-irradiated a-C:H film. The nano-columnar a-C:H film modified by EB-irradiation has non-linear elasticity where indentation displacement should be reversible up to 8% of film thickness. Owing to this ordering and densification via EB-irradiation, softening both in stiffness and hardness takes place with increasing the irradiation time.

Different reactivity of ions has been implanted into Zr-Cu metallic glass to obtain nano-structured surface with controlled elasticity. The penetration of glass forming element of Ni+ into crystalline Zr-Cu stabilizes glassy phase to induce crystalline-amorphous (c-a) transition during implantation process. In the meanwhile, penetration of N+ into glassy matrix induces precipitation of (Zr, Cu)N at the mean penetration depth of N. Critical N concentration for nitride formation is estimated to be (Zr,Cu)-20at%N, which also suggests existing of N solid solution of glassy phase. Inert element of Ar+ yields dispersion of nano-voids among glassy matrix. Nano-indentation tests reveal that Young’s modulus of ion implanted glassy film dramatically changes with respect to the induced nano-structure, to decrease 0.4 times for Ar+, to increase 1.3 times for N+ as comparison with that for as-deposited state.

Fundamental studies on the thermoelectricity have been mainly done in the pseudo binary systems of Mg2Si – Mg2Ge – Mg2Sn. In recent years, their thermoelectricity is revisited because of light-weight, low initial const and short turning back time in addition to high potential in figureof- merit for ZT approaching to unity or more. Conventional melting and solidification, or, normal PM routes fail in precise, wide-range control of chemical composition and microstructure control. New PM route via bulk mechanical alloying is developed to fabricate the solid solution semiconductive materials with Mg2Si1-xGex and Mg2Si1-ySny for 0 < x, y < 1 and to investigate their thermoelectric materials. Since Mg2Si is n-type and both Mg2Ge and Mg2Sn are p-type, pntransition takes place at the specified range of germanium content, x, and tin content, y. Through optimization of chemical composition, solid-solution type thermoelectric semi-conductive materials are designed both for n- and p-type materials. In addition, appropriate doping condition can be searched in the specified range of x and y.

Magnesium base alloys and compounds are attractive for various applications as a functional material. In particular, a series of binary system by Mg2X (X = Si, Ge, Sn and Pb) has fascinated many researchers and engineers by its thermoelectric properties and semi-conductive performance. Many barriers in its processing rejects precise investigation of these types of semiconductive compounds: high vaporizing pressure and mechanical adhesion of magnesium, reaction of germanium and tin with crucibles, and, difference of melting point among elements, X. Solidstate processing via the bulk mechanical alloying enables us to directly fabricate these Mg2X semiconductive materials in high density performs. The precise control of chemical composition leads to an investigation on the dilution and enrichment of X in Mg2X. Two types of solid-state reactivity are introduced: e.g. synthesis of Mg2Si from an elemental mixture Mg – Si, which is a nucleationcontrolled process, while synthesis of Mg2Sn from Mg – Sn is a diffusion-controlled process. The thermoelectricity of these Mg2X is evaluated for discussion on the validity and effectiveness of this new PM route as a reliable tool for fabrication of thermoelectric compounds.

Ellipsometric characterization on the basis of multi-layered modeling is proposed to describe the optical and electrical property transients of hydrogenated films. In particular, two-step modeling is developed to make ellipsometric characterization on the yttrium film and the palladium capped yttrium film deposited on the SiO 2 glass substrate. In the former, Y 2 O 3 film deposited on SiO 2 substrate is prepared to estimate the dielectric response of yttrium oxide layer as the first step. These data are further utilized in the second step to determine optical and electric properties of yttrium-base multi-layers which are composed of metallic yttrium, composite of metallic yttrium and Y 2 O 3 , and Y 2 O 3 layer with surface roughness. In the latter, a palladium film deposited on SiO 2 substrate is prepared to investigate the dielectric response of palladium hydrides. The estimated dispersion functions are further used in the multi-layered modeling for hydrogenated Pd-capped yttrium films on the SiO 2 substrate. Under the ambient hydrogen pressure, palladium coated yttrium films have low resistivity and hydrogenated yttrium is still metallic. This palladium coating works as a top capping layer for yttrium film during hydrogenation and de-hydrogenation.

Bulk mechanical alloying with combination of hot pressing is proposed to prepare Mg 2 Si 1− x Sn x ( x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) solid solutions as thermoelectric materials from elemental granules. Hot pressing condition is optimized in order to obtain higher figure of merit. Temperature dependence of the electrical conductivity, the Seebeck coefficient and thermal conductivity were measured from the room temperature up to 700 K. It was found that the thermoelectric properties of Mg 2 Si 1− x Sn x were sensitive to the tin concentration. The p–n conversion takes place at the vicinity of x = 0.2, where the Seebeck coefficient drastically changes its sign. A maximum figure of merit of 0.13 was obtained at 653 K in the samples with nominal compositions of Mg 2 Si 0.4 Sn 0.6 and Mg 2 Si.

High density oxygen plasma-etching was applied to microtexturing onto the diamondlike carbon (DLC) films coated on the die-unit substrates. This mold-die unit with microtextured DLC coating was fixed into a cassette die for computer numerical control (CNC) stamping with the use of precise control both in loading and feeding the sheet materials. In particular, the pulsewise-motion control in stamping was employed to describe the effect of loading and unloading subsequences in the incremental motion on the microtexturing with reference to the normal loading motion. The macroscopic plastic deformation as well as the microscopic metal flow were studied to prove that the pulsewise-motion should be responsible for homogeneous duplication of microcavity patterns into a pure aluminum sheet with high aspect ratio.

Magnesium base compounds have unique properties as a functional material. The conventional melting and solidification and mechanical attriting/grinding methods have to suffer from various difficulties in synthesis of these compounds: large difference in melting temperature among elemental constituents and various contaminations in material processing. Bulk mechanical alloying (BMA) is attractive for solid-state synthesis of these types of magnesium compounds, especially Mg2X for X=Si and Sn. High dense, single phase Mg2X compact is successfully fabricated by this processing. Electrical conductivity of Mg2X is measured to describe its semi-conductivity. This solid-state reaction at room temperature is mechanically induced during BMA so that the solid-state reactivity is dependent on the physical properties of each element X. In the case of ductile–brittle phase system like Mg–Si, its solid reaction process is directly controlled by mechanical refinement of silicon particle size in the magnesium matrix. In the case of ductile–ductile phase system like Mg–Sn, its solid-state reactivity is enhanced by the repeated plastic flow of ductile constituents. The above mechanically induced solid-state reaction process is described with consideration of formation enthalpy ratio in Mg–X system varying during BMA. Transient behavior of thermoelectricity from metallic state to semi-conductive one is also described by the simple mixture rule of this formation enthalpy ratio.

Profound understanding and survey of magnesium base intermetallic compounds is hindered by various difficulties in their processing and fabrication. Solid-state synthesis via the bulk mechanical alloying (BMA) is free from contaminations and segregation through high reactivity of elemental constituents against crucibles or vials. Magnesium–tin system is employed to demonstrate the solid-state reactivity to Mg2Sn from the elemental powder mixture. This process is characterized by the gradual solid-state reaction to Mg2Sn with processing time. Since the blended mixture of magnesium and tin with the initial molar ratio of Mg66.7%Sn33.3%, is repeatedly strained via BMA in the controlled conditions, the solid-state reaction advances monotonically with refinement of interparticle distance between magnesium and tin. Ternary semi-conductive compounds, Mg2Si1� xSnx for 0 5 x 5 1, are also synthesized by this process. Thermoelectric properties of this ternary alloy are investigated to discuss the effect of tin content on the band-gap, the thermal conductivity, the Seebeck coefficient and the figure-of-merit. In addition, these data are compared to the previously reported results by using melt and solidified samples in order to describe the common features in the solidsolution type thermoelectric compounds. Furthermore, p–n transition behavior is also reported in this ternary alloy system.

Mg-Co system is employed to investigate the solid-state reactivity of Mg 2 Co from the elemental powder mixture of magnesium and cobalt and to describe the hydrogenation and de-hydrogenation processes of Mg 2 Co. Mg 2 Co is successfully solid-state synthesized as a non-equilibrium phase compound by the bulk mechanical alloying. This solid-state reactivity is controlled by the repeated plastic flow of ductile elements in the powder mixture. This non-equilibrium phase, Mg 2 Co is stable up to 833 K. Its hydrogenation and de-hydrogenation processes are described by DSC, PCT and XRD. These processes take place in multi-step with strong dependency on the holding temperature. Hydrogenation process from Mg 2 Co is composed of two steps to Mg 2 CoH 5 and dehydrogenation from Mg 2 CoH 5 , one step to Mg 2 Co, at 633 K. Maximum hydrogen absorption capacity at 633 K is still limited to 2.03 mass% since hydrogenation and de-hydrogenation steps, working at higher temperature, are never activated without chemical modification to original Mg 2 Co.

Low weight and long life-time are necessary requirements for automobiles to significantly reduce CO 2 emission and environmental burdens in their use. Aluminum alloys are one of the most promising materials selections for automotive power-train parts and electrical components to reduce their weight and to increase their specific strength. Reliable protective layers for these aluminum parts are indispensable to improve the wear resistance and to reduce the friction coefficient. Among several methods, the precipitate-accommodated plasma nitriding is proposed as a new surface treatment of aluminum alloy parts to significantly increase the aluminum nitride formation rate and to control the nitrided layer thickness. Microstructure characterization and hardness profile measurement are carried out to describe the formation of uniform nitrided layer. Pin-on-disc method is used for dry wearing test to prove that wear volumes as well as friction coefficients are reduced by this AlN protective layer. Low flash temperature and low specific wear volume prove that the present nitriding process is one of the most promising surface treatments for aluminum alloy parts in dry wearing conditions.

In situ formation of tribofilms is indispensable to reduce the wear volume and friction coefficient in dry. These tribofilms must be robust even in working at high normal pressure and sliding velocity between work materials and tools. Although TiN and TiC ceramic coating films are frequently utilized as a protective coating for dies and cutting tools, they often suffer from severe, adhesive wearing in dry forming and machining. Chlorine ion implantation assists lubricious oxide film to be in situ formed during wearing. At the presence of chlorine atoms in the inside of TiN or TiC films, in situ formation of lubricous intermediate titanium oxides with TiO and TinO2n−1 is sustained to preserve low frictional and wearing state. The fundamental process of this self-lubrication mechanism on the tribofilms, is discussed together with microscopic analysis and observation of worn surface and wear debris. The self-lubrication process works well in dry machining in order to reduce the flank wear of cutting tools even in the higher cutting speed range up to 500 m/min.

Quasi-static compressive response of regularly cell-structured materials is experimentally studied for various relative density, cell contact length and intercell bonding state. Each cell in this specimen is aligned in a hexagonal closed-pack array. The contact length as well as cell wall thickness of regularly cell-structured materials, plays an important role on the deformation mode transition. The deformation changes itself from symmetric to asymmetric pattern when increasing the contact length to cell-wall thickness ratio. Higher level of collapsing stress is observed in symmetric deformation due to the nearly uniform stress transfer during compression. Work hardening behavior is promoted with increasing the relative density or decreasing the contact length. Asymmetric deformation is associated with a nearly constant collapsing stress. The plateau collapsing stress state is caused by the localized deformation of cell-row in a narrow band of specimen. Liquid epoxy resin between cell walls also influences on the deformation mode of cell-structured materials. In the present study, the experimental observation is presented first (Part 1), followed by the theoretical analysis and comparison between experimental and analytical results in (Part 2).

A new computational mechanics model is proposed to describe the compression response of two-dimensional cellular materials with consideration of microstructural development. In this modeling, processing conditions to fabricate cellular materials are taken into account as a cell-growth mechanism. Representative volume elements (RVE) are generated by the phase-field model. Numerical simulations of compressive deformation are performed by finite clement analysis for the selected RVE. The cell size distribution especially affects on the limit stress and the densification process.

Solid solution Mg 2 Si 1 - x Ge x for various concentration of germanium, x, is successfully prepared in single phase by the bulk mechanical alloying (BMA) and the hot pressing (HP). Both BMA and HP process conditions were optimized to yield high dense samples with fine, homogeneous microstructure. The electrical conductivity, the Seebeck coefficient and the thermal conductivity are measured from room temperature up to about 700 K. The Seebeck coefficient is much sensitive to the germanium content, x in Mg 2 Si 1 - x Ge x . The pn-transition takes place at x = 0.35 where the Seebeck coefficient drastically changes its sign. The measured band gap of Mg 2 Si 1 - x Ge x decreases with x from 0.71 to 0.54 eV. The figure of merit at 613 K of Mg 2 Si 0 . 6 Ge 0 . 4 reaches 0.34 x 10 - 3 K - 1 in the case of BMA for N = 600 and HP at 773 K by 1 GPa for 3.6 ks.

Thermoelectric p-n modules are prepared by the spark plasma sintering ( SPS) solid bonding for experimental and theoretical evaluation on their thermoelectricity. Both p-type (Bi 0 . 4 Sb 1 . 6 Te 3 ) and n-type (Bi 2 Te 2 . 8 5 Se 0 . 1 5 ) materials are prealloyed from elemental granule mixture via the bulk mechanical alloying, shear-extruded to control their anisotropic texture and joined to fabricate p-n modules. The mutual atomic diffusion layer across the p-n interface is controlled down to 2 μm, 0.04 times narrower than that for hot-pressed p-n interface. Open-circuit voltage and resistance of p-n modules are measured for various interface layer height. They are compared with theoretical estimates via the computer-aided analysis. Analytical expressions are proposed to estimate the thermoelectric characteristics on p-n module. The power generation characteristics of p-n modules is also evaluated for various temperature differences between cold and hot sources.

The reaction induced phase separation aimed for the distribution of nano-structured particles has been investigated by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) in ternary Ti-Si-N film via N+ implantation. The fabrication of Ti-20at%Si film has made on Si substrates by ion beam sputtering (IBS), and then N+ implantation with 50 keV has been conducted on these films. The selected area electron diffraction (SAED) from as-deposited film shows amorphous Ti-Si. As-deposited Ti-Si film exhibited high stability even for the heat treatment at 773K for 3600s. N+ implantation induced the direct formation of nano crystalline of fcc-TiNx within the Ti-Si film. The XPS depth profiling and chemical shift suggest that the preferential nitriding of Ti accompanied with the segregation of SiNx occurred during N-implantation.