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Graphite is useful in high-temperature applications in many engineering fields, such as heat-treating, brazing, and sintering industries. As the operation becomes severe, carbon experiences degradation leading to failure. In this study, a protective coating of W and Mo as the intermediate layer by air plasma spraying on graphite substrate was investigated to find a better intermediate layer. Their performance was explored as a bonding layer in a protective alumina-YSZ ceramic topcoat. X-ray diffraction and scanning electron microscope were used to observe the cross-section of coatings and the difference in the bonding characteristics between W and Mo, respectively. W was found inferior to Mo as a bonding performance over 1450 °C in view of carbide formation against the thermodynamic data. It seems to be related to the formation of a barrier layer as oxide during air plasma spraying.

AlCrSiN film with a composition of 29.1Al-17.1Cr-2.1Si-51.7N in at. % was deposited on a steel substrate by cathodic arc ion plating at a thickness of 1.8 μm. It consisted of nanocrystalline hcp-AlN and fcc-CrN, where a small amount of Si was dissolved. Corrosion tests were carried out at 800 °C for 5–200 h in Ar-1%SO2 gas. The major corrosion reaction was oxidation owing to the high oxygen affinity of Al and Cr in the film. The formed oxide scale consisted primarily of (Al,Cr)2O3, within which Fe, Si, and S were dissolved. Even after corrosion for 200 h, the thickness of the scale was about 0.7–1.2 μm, indicating that the film had good corrosion resistance in the SO2-containing atmosphere.

The effects of pH and the organic additive, polyethylene glycol (PEG), on the trivalent chromium electroplating were investigated in view of the solution stability, electrochemical reactions and the properties of deposited layer. It was sought out that the concentration of chromic complexes in the chromic bath with formic acid was closely dependent on pH. The chromic complex formation in the bath, examined by theoretical calculation and UV–vis absorption measurement, was not affected by PEG addition. However, adsorbed PEG molecules on the cathode surface caused the hydrogen evolution rate to be retarded and the deposited coating morphology smooth, small cracks and nodular structure. The variations of solution acidity and organic additive concentration affected the complex formation, the cathodic reaction and the physical property of the deposit.

The mechanism of chromium metal deposition from a trivalent chromium bath containing formic acid and polyethylene glycol 1000 (PEG) was studied on an electrochemical quartz crystal microbalance (EQCM), electrospray ionization mass spectrometry (ESI-MS) and a technique for measuring pH on the cathode surface. Reactions of PEG molecules with trivalent chromium ions and their influence on the plating process of trivalent chromium were investigated. EQCM studies at low trivalent chromium ion concentrations show that chromium electrodeposition occurs via the formation of an adsorption layer on the electrode surface, which is called a cathodic film. Cathodic films hinder the penetration of ions from bulk solution to the cathode surface. In the inner portion of the cathodic film and at the cathode surface, intermediate complexes were formed during the deposition process. ESI-MS revealed that the PEG molecules were stable in a trivalent chromium bath containing potassium formate. During electroplating, the PEG molecules decreased the reductive current of hydrogen compared with solutions without PEG; an effect that was also observed due to the pH on the electrode surface. PEG plays a decisive role in the formation of intermediate compounds during electrodeposition.

The effect of organic additives, polyethylene glycol (PEG), on the trivalent chromium electroplating was analysed in the view point of current efficiency, solution stability and metallurgical structure. It was measured that PEG-containing trivalent chromium solution had about 10% higher current efficiency than pure solution and controlled the micro-crack density of electrodeposits. PEG exhibited profound effect on the solution stability by reducing the consumption rate of formic acid which acts as a complexant to lower the activation energy required for electrochemical reduction of trivalent chromium ions. It was also revealed that the formation of chromium carbide layer was facilitated in the presence of polyethylene glycol, which meant easier electrochemical codeposition of chromium and carbon, not single chromium deposition. Trivalent chromium layer formed from PEG-containing solution was amorphous with local nano-crystalline particles, which were prominently developed on the entire surface after non-oxidative heat treatment.

The effect of solution acidity and organic additives, polyethylene glycol (PEG), on the trivalent chromium electroplating was systematically investigated in the view point of electroreduction of trivalent chromium ions and solution stability. It was found that solution acidity controlled at pH 2.5 showed the widest current range for bright electrodeposits in the presence of PEG additives, which reduced the local current intensification at high current densities. Through complex interaction between PEG additives and hydrogen ion, that is, solution acidity, electrode potential was moved in the negative direction in the bulk solution, while it shifted in the positive when electric potential was scanned. In conjunction with electrochemical quartz crystal microbalance (EQCM), it was found that PEG additives had a role in promoting the electron transfer to trivalent chromium ion complexes in bulk solution and their adsorption at the electrode surface as well as interfering with hydrogen ion reduction process below pH 2.5. The PEG additives developed the nodular morphology during electroreduction of trivalent chromium ions with the increase of solution acidity and enhanced its current efficiency by maintaining the consumption of complexant, formic acid, at low speed.

Thermal barrier coatings (TBCs) have been widely used in various gas turbines for aircraft propulsion and power generation. TBCs consist of a metal bond coat and a ceramic top coat of YSZ. It is generally known that the TBC′ life strongly depends on the thermally grown oxide (TGO) because failure of TBCs occurs when the TGO reached a critical thickness. In this study, ion implantation of novel elements has been made on the bond coat which acts as an oxidation barrier for suppressing the TGO growth. The effects of type of ion implanted elements on the TGO formation were investigated. The oxidized specimens at 1150 °C were characterized by SEM, XRD, RBS and AES. From the results, CoNiCrAlY bond coat with an oxidation barrier was found to be effective in suppressing growth of the TGO.

Coatings of Ni-17 at.%W were electroplated on a steel substrate, and their corrosion behavior was investigated between 600 and 800℃ in an Ar-0.2%SO₂ atmosphere. They delayed the corrosion of the steel substrate. They were corroded into an outer NiO-rich layer, and an inner (WO₃+NiO+NiWO₄)-mixed oxide layer. Below these oxide layers, a sulfide layer gradually formed.

The structural characteristics of the trivalent chromium deposits and their interfacial behavior in the plating solution with and without polyethylene glycol molecules were observed by using various electrochemical methods such as cyclic voltammetry, open circuit potential transition, electrochemical impedance spectroscopy, scanning electron microscopy and X-ray photoelectron spectrometry. It is shown that the polyethylene glycol molecules make the reductive current density lower in the trivalent chromium plating system and promote a hydrogen evolution reaction through their adsorption on the electrode surface. And the trivalent chromium layer formed from the polyethylene glycol-containing solution has somewhat higher density of cracks on its surface and results in a lower film resistance, lower polarization resistance, and higher capacitance in a corrosive atmosphere. It is also revealed that the formation of chromium carbide layer is facilitated in the presence of polyethylene glycol, which means easier electrochemical codeposition of chromium and carbon, not single chromium deposition.

The effect of cationic additive on Cr/nanodiamond plating was studied. Chromium plating was performed in Sargent bath. Morphology of deposit was observed by scanning electron microscope(SEM); microhardness by hardness tester; wear rate by tribometer; amount of diamond in deposit by combustion method and passivity by potentiodynamic scan. Experimental results show that in the presence of cobalt cation, the amount of nanodiamond particle in the deposit is increased. With increasing diamond particle amount, the metallurgical, mechanical and electrochemical properties of Cr/nanodiamond deposit are improved. However, this improvement seems to be constrained. In the presence of 10 g/L of nanodiamond powder and 2.5 g/L of cobalt cation in the bath, the amount of diamond particle in deposit is increased by 4 times; and wear rate of Cr-Co/nanodiamond deposit is decreased by 2–3 times as compared with pure Cr/deposit. The passive current of Cr-Co/nanodiamond composite deposit is decreased from 18 to 8 μA. The morphology of Cr/nanodiamond is smooth remarkably in the presence of cobalt cation.

Micron-sized WC-Co powder (powder) was coated onto an 420J2 steel substrate and the bond coats (BCs) of Ni, NiCr, and Ni/NiCr using high-velocity oxy-fuel thermal spraying to study the surface properties, friction behavior, and tensile bond strength of the WC-Co coating (WC-Co) on the 420J2 substrate (sub) and the BCs of Ni, NiCr, and Ni/NiCr. During the spray coating, a small portion of WC decomposed to the less-hard W 2 C, W, and free carbon above its decomposition temperature of 1250 °C, decreasing hardness and increasing porosity. The surface hardness of 1120 ± 100 Hv (10,980 ± 980 MPa) depended strongly on the spray parameters. It was three to four times harder than metals and alloys, but less than one-half the hardness of binder-less pure WC (2400 Hv). Free carbon reacted with the sprayed oxygen gas and formed carbon oxide gases, resulting in a coating of 4.3 ± 1.0% porosity. The friction coefficient of the coating increased about 17% with increasing surface temperature: 0.65 ± 0.03 at 25 °C to 0.76 ± 0.06 at 500 °C because of the increased local cold-welding of the asperities at the higher temperature of 500 °C. Sub/WC-Co, sub/Ni/WC-Co, sub/NiCr/WC-Co, and sub/Ni/NiCr/WC-Co had tensile bond strengths of 9600 ± 300 psi (66.2 ± 3.4 MPa), 6300 ± 200 psi, 6000 ± 200 psi, and 7500 ± 200 psi, respectively. The fracture locations of all coatings were at interfaces with the WC-Co coating, indicating that the adhesion of the WC/Co inside coating was higher than 9600 ± 500 psi and that the adhesion of WC-Co on the substrate (9600 ± 500 psi) was much higher than the adhesion on the BCs.

Plasma nitriding is a promising posttreatment technique to create a nitride layer on electroplated chromium coatings for improving their corrosion resistance. In the present study, the effects of plasma nitriding on the corrosion properties of electroplated chromium/C45 mild steel were investigated using electrochemical characterization. The chromium plated samples were nitrided using a pulsed direct current glow discharge in an NH3 atmosphere. The polarization curve measurement results showed that the plasma nitrided samples exhibited more positive corrosion potentials (Ecorr), smaller corrosion currents (Icorr), and evident passivation when compared with unnitrided chromium plating/substrate system. The high value of Ecorr and low value of Icorr imply an improvement of the corrosion resistance of the coating/substrate system after plasma nitriding.

A study on chromium matrix composite plated with nanosized diamond powders was undertaken by employing a standard Sargent bath. Chromium matrix composite plated with nanosized diamond powders manifested super properties. The microhardness was varied from 890 to 920 HV (load 25 g/f), as compared with 801 HV of pure chromium; the wear resistance was increased 3-4 times. The potentiodynamic measurement in a chloride medium showed that the passive current of chromium matrix composite plated with nanosized diamond powder was 6 times as lower as that of pure chromium. Microscopic observation indicated that nano-diamond powders were included in the chromium deposit in the form of single and multi crystalline.

Tin-doped indium oxide (ITO) films were deposited at ∼ 70 °C of substrate temperature by radio frequency magnetron sputtering method using an In2O3–10% SnO2 target. The effect of hydrogen gas ratio [H2 / (H2 + Ar)] on the electrical, optical and mechanical properties was investigated. With increasing the amount of hydrogen gas, the resistivity of the samples showed the lowest value of 3.5 × 10− 4 Ω·cm at the range of 0.8–1.7% of hydrogen gas ratio, while the resistivity increases over than 2.5% of hydrogen gas ratio. Hall effect measurements explained that carrier concentration and its mobility are strongly related with the resistivity of ITO films. The supplement of hydrogen gas also reduced the residual stress of ITO films up to the stress level of 110 MPa. The surface roughness and the crystallinity of the samples were investigated by using atomic force microscopy and x-ray diffraction, respectively.

In this work, molybdenum and tungsten ions were implanted onto the DLC films deposited by filtered cathodic vacuum arc. We investigated the effects of ion species and doses on carbon related bonding property such as the ratio of sp 3 carbon to sp 2 phase, the chemical composition and tribological properties of the DLC films in the range of 200 to 600 °C. The oxidation starting temperature decreased with an increasing ion dose and ion mass owing to higher sp 2 carbon fraction. Oxidation of the implanted-metal element, however, keeps the DLC film from carbon sublimation by oxidation, offering stable tribological characteristics by covering it with a metal oxide layer at the high temperature.

Plasma source ion implantation (PSII) treatment was undertaken to improve the mechanical properties of electrodeposited trivalent chromium layers. Nitrogen ions were implanted, with energies of − 15 to − 25 keV and doses of 1, 5 and 10 × 1017 atoms cm− 2, to modify the surface properties of Cr plating layer. The surface properties of the films were characterized by XRD, SEM, ruby-ball on disk type tribometer and nanoindenter. Polycrystalline CrN films with (200), (220) and (222) orientations were preferentially grown and numbers of surface cracks were increased by N+-PSII onto trivalent chromium layers. The surface hardness of the Cr3+ plating layer was increased from 16 to 25 GPa by N+-PSII. Severe wear and higher friction was observed on N+-PSII treated trivalent Cr plating. It seemed that the wear debris from hardened and cracked surface of the N+-PSII treated specimen prompted abrasive wear in the wear test. Roughness of the Cr3+ plating layers was smoothed with increasing implantation doses.

Cr–Al–N, Cr–Si–N, Cr–Al–Si–N coatings were successfully deposited on WC–Co substrates by a hybrid coating system combining an arc ion plating technique using Cr target, and a magnetron sputtering method using Al and Si targets under N 2 /Ar atmosphere. XRD, HRTEM, and XPS analyses revealed that the synthesized Cr–Al–N coatings consisted of solid-solution (Cr,Al)N crystallites, and the Cr–Si–N and Cr–Al–Si–N coatings with Si content of ∼ 9 at.% were fine composites consisting of (Cr,Si)N and (Cr,Al,Si)N crystallites, respectively, embedded in an amorphous Si 3 N 4 /SiO 2 matrix. The hardness values of the Cr–Si–N (∼ 35 GPa) and the Cr–Al–Si–N (∼ 55 GPa) coatings were significantly increased compared with those of CrN (∼ 23 GPa) and Cr–Al–N (∼ 25 GPa) coatings. Besides, the average friction coefficients of the Cr–Si–N (∼ 0.30) and the Cr–Al–Si–N (∼ 0.57) coatings with Si content of about 9 at.% were largely decreased compared with those of CrN (∼ 0.50) and Cr–Al–N (∼ 0.84) coatings. A comparative study on microstructural characteristics among Cr–Al–N, Cr–Si–N, and Cr–Al–Si–N coatings is reported in this paper.

Nickel plating is investigated using an electrochemical method in this study. Cathodic polarization indicated that electrode polarization at a current density of 10−1 A/cm2 increased by approximately 100 mV in a pH range 3–5, and by nearly 150 mV with 1 g/L of carbon powder in a Watts solution, as compared to bare nickel. The influence of inert particles such as carbon powder, silicon carbide and rice husk ash included in the nickel deposit was studied further using a potentiodynamic technique. Results showed that a co-deposit of nano-particles increased cathodic polarization. With a three-fold increase of the carbon powder in the plating solution, the polarization potential of the nickel deposit was doubled at a current density of 10−2 A/cm2. Passivation of the nickel deposit in the presence of all of the inert particles studied was improved in the area of hundreds of times higher compared to a bare nickel deposit. By increasing the amount of inert particles to twenty times the original amount, the passive current density was decreased by 85–95%. A co-deposit of rice husk ash in the nickel deposit decreased the passive current density by 98%, compared to a carbon and silicon carbide powder. Thus, rice husk ash has the potential to improve the pitting corrosion resistance of nickel composite plating.

The oxidation of Cr-12.7 at.%C coatings electrodeposited on steel was studied at 700 and 800oC in air. The coatings, which consisted of nodular grains having microcracks and pits, had either an amorphous or a microcrystalline structure. They changed to crystalline Cr during oxidation. The oxidation resulted in the formation of Cr2O3, which provided good oxidation resistance to the coating. However, the presence of microcracks and pits in the coating was harmful to oxidation resistance.

Plasma nitrocarburizing was carried out on the hard chromium coating deposited on SM45C mild carbon steel substrate by electroplating. After plasma nitrocarburizing at 720 °C for 20 h, a 6–7-μm-thick nitride layer consisting of CrN and Cr 2 N was formed on the surface of Cr coating with the microhardness of about 950–1100 HV0.1. Due to the effect of annealing caused by plasma nitrocarburizing process at higher temperature and the Cr being a strong carbide-forming element, the carbon in steel substrate diffused outward into the Cr coating and reacted with Cr forming Cr carbide interface layer between the Cr electroplating and substrate. The nitrogen going into the microcracks and the volume increase accompanied by Cr nitride and carbide formation would cause the microcracks inherent to hard chromium plating disappear and improve its corrosion resistance. The microstructures of nitride and carbide layers were studied using X-ray diffraction and cross-sectional transmission electron microscopy.

Bi 3.4 Dy 0.6 Ti 3 O 12 (BDT) thin films have been successfully deposited on Pt(1 1 1)/Ti/SiO 2 /Si and p-type Si(1 0 0) substrates by a sol–gel spin coating process. The remanent polarization (2 P r ) and coercive field (2 E c ) values of the BDT thin film on Pt(1 1 1)/Ti/SiO 2 /Si substrate annealed at 700 °C were 39 μC/cm 2 and 367 kV/cm at an electric field of 400 kV/cm, respectively. This 2 P r value is larger than that of lanthanum-substituted Bi 4 Ti 3 O 12 thin film and comparable with those of the samarium or neodymium-substituted Bi 4 Ti 3 O 12 thin films. Moreover, the BDT thin film capacitors did not show a significant fatigue up to 1.45×10 10 switching cycles at a frequency of 1 MHz. The BDT thin films on p-type Si(1 0 0) substrates exhibit good capacitance–voltage ( C–V ) characteristics and a memory window of approximately 1.2 V with sweep voltage of ±10 V. The humps and valleys observed in C–V curves were interpreted by introducing charge injection from semiconductor to ferroelectrics. Furthermore, the frequency and the temperature dependency of C–V characteristics for the metal-ferroelectrics-semiconductor structured BDT thin films were measured. From these results, we suggest that the BDT thin film is one of the suitable dielectric materials for ferroelectric random access memory applications.

The effect of formic acid and current density on the crystal structure, surface morphology and crystallization of intermediate Cr-C layers deposited in both hexavalent and trivalent chromium baths were studied to observe chrome-carbide formation behavior and to develop an environmental protective Cr-C electroplating technology. Formic acid in hexavalent and trivalent chromium baths effectively produces intermediate Cr-C layers. The intermediate Cr-C layers has initially amorphous type microstructure. Crystallization of the intermediate Cr-C layer occurs at a current density above 27.5 A/dm 2 in a trivalent chromium bath and above 100 A/dm 2 in an hexavalent chromium bath, respectively. The carbon content of the intermediate Cr-C layer prepared in hexavalent chromium bath is twice as much as that of the layer prepared in trivalent chromium bath. Cr 23 C 6 and Cr 7 C 3 were observed in the intermediate Cr-C layer prepared in hexavalent chromium bath, whereas, Cr 23 C 6 was formed in the layer prepared in trivalent chromium bath after vacuum annealing at 800 °C.

Effects of boric acid introduced into an ammonia-citric plating bath were studied both on the plating process and on the deposit characteristics. It was found that boric acid increased not only current efficiency but also tungsten content of the deposits, implying that boric acid may act as a surfactant to impede the proton reduction and also form some complex with tungstate to be beneficial for tungsten co-deposition. The deposit hardness increased firstly with increasing tungsten content but then decreased as tungsten content was beyond 42 wt.%. The reasons lie mainly in both the Hall–Petch and the reverse Hall–Petch effects rather than solid–solution strengthening when the grain (or domain) size of the Ni–W alloy was in the nanometer scale.

Amorphous bright chromium deposit was electroplated in a modified Sargent bath containing formamide. It was evaluated that this film had no cracks and carbon incorporated was distributed uniformly from the examination of cross-section of deposit with scanning electron microscope and Auger electron spectroscopy. Hardness increased from Hv 1300 to 1700 after annealing at 600 °C owing to crystallization. This Cr–C amorphous film was applied to chromium deposit as an inner layer in order to enhance corrosion resistance. Besides, plasma nitriding on chromium deposit was carried out in mixed gas atmosphere of NH3 95% and CH4 5% as a post-treatment. Surface nitride layer, CrxN, and carbide layer at the interface between chromium deposit and substrate were formed without any cracks after nitriding. Duplex coating of Cr–C/Cr and Cr/CrxN was achieved and salt spray test was performed for elucidation of corrosion resistance. Corrosion resistance of double layers was improved remarkably by an inner layer of Cr–C and by an outer layer of CrxN. These crack-free layers were considered to play a key role to enhance corrosion resistance of chromium electrodeposit.

Effects of brightener 2-butyne-1,4-diol on plating process and structures of Ni–W electro-deposit were investigated by means of cyclic voltammetric measurement, SEM and atomic force microscopy (AFM). A full-bright and smooth Ni–W alloy can be electrodeposited as 2-butyne-1,4-diol is added in the plating bath, but 2-butyne-1,4-diol decreases W content gradually in the deposit and current efficiency rapidly with its concentration. 2-Butyne-1,4-diol in the solution is in favor of hydrogen evolution reaction to decrease current efficiency. Bright Ni–W deposit has much lower root mean square (RMS) surface roughness than corresponding dim one and the RMS difference reduces with W content of the deposit. However, when measured area is 0.1×0.1 μm 2 , RMS roughness of bright Ni–W alloy is higher than that of corresponding dim one. It may result from the more micro-defects in the bright deposit. Grain size of bright deposit is much smaller than corresponding dim one and the grain size difference decreases with increasing W content in the deposit. When W content is more than 42 wt.% (near to the eutectic point in Ni–W equilibrium diagraph), one could not observe grain with AFM.

TiN films were deposited onto AISI D2 steels by an arc ion plating (AIP) technique. The effects of atmospheric humidity and counterface materials on the tribological behavior of the AIP-TiN layer have been investigated using a conventional ball-on-disc wear apparatus. In the case of a steel counterface, the average friction coefficient increased with increasing relative humidity due to tribochemical interaction of the steel with moisture. At low relative humidity (2% RH) condition, the TiN coating layer rather gained mass due to the seizure of steel on the layer without the tribochemical reaction. For the higher humidity condition above 25% RH, the mass loss of the TiN coating layer occurred and was accelerated with the increase of the relative humidity as the tribochemical reaction was progressively dominant. In the case of the alumina counterface, the friction coefficient decreased with increasing relative humidity from 2% RH to 25% RH. This behavior was explained by the formation of the aluminum–hydrated oxide phase between counterface materials. On the other hand, the increasing relative humidity up to 85% RH induced a large increase of both average friction coefficient and its deviation, in addition, increased the wear rates of both counterface layers. This behavior was explained with the accelerated fracture of the alumina ball due to the reduced flexural strength in moist conditions.

The oxidation behavior of TiCrN coatings having compositions of Ti 36 Cr 26 N 38 , Ti 31 Cr 35 N 34 and Ti 14 Cr 52 N 34 was studied between 700 and 1000°C in atmospheric air. The oxidation resistance of TiCrN coatings which were composed of TiN and CrN phases increased in the order of Ti 36 Cr 26 N 38 , Ti 31 Cr 35 N 34 and Ti 14 Cr 52 N 34 , implying that chromium within the coating played a decisive role in providing the oxidation protection. The oxides formed always consisted of TiO 2 and Cr 2 O 3 . During oxidation, all the involved elements diffused either outwardly or inwardly, depending on the concentration gradients. The substrate elements diffused outwardly toward the oxide-gas interface, oxygen from the atmosphere diffused inwardly and the coating elements diffused predominantly outward.

The so-called ‘black’ layer between PVD TiN coating and an ion nitrided surface was observed by SEM and TEM to investigate the detailed microstructure of the interface and the delamination mechanism of the TiN film. Two distinct sublayers were observed in the black layer. The upper sublayer was of very fine grains and the lower region of 10 times larger grains. The fine grains were irregular and around 50 nm in size. The larger grains of the lower sublayer were similar to the compound layer underneath. A Ti-based film was deposited on the surface of the black layer during Ti ion bombardment in a cathodic arc ion plating method and identified as TiN and Ti phase. The TiN film deposited during Ti ion bombardment was of a very fine grain size and had a strong preferential arrangement of (200) plane perpendicular to the surface. A lot of pores were observed along the interface between the TiN film and the upper sublayer. It is suggested that the cracking and delamination of the TiN film be initiated at these pores during the scratch adhesion test, which thereby decreased the adhesion strength of the TiN film.

In order to investigate the interfacial structure between TiN and iron nitride, an AISI 4140 steel was nitrided to form a layer of thickness 15 μm by DC ion nitriding, then the surface was bombarded with Ti ions and subsequently coated a TiN film of 5 μm by arc ion plating method. The interfacial microstructure between TiN and iron nitride was characterized by optical microscope, SEM and XRD. The so-called `black' layer was observed in the duplex treatment. It resulted from the decomposition of iron nitride during the bombardment. Its thickness was increased with increasing bombardment time at high bias voltage. But the thickness was greatly decreased when the iron nitride was bombarded with a nitrogen gas or at a reduced bias voltage. The adhesion strength of the top TiN coating was decreased with increasing thickness of the black layer. Furthermore, the reduced adhesion strength in this system was discussed in view of the interfacial structural relationship between TiN and iron nitride.

Plasma-assisted bonding was carried out on low-alloy steels with no subsequent heat treating in order to provide a substitute for high-alloy steels. It was found that arcing in the glow discharge of a BCl 3 -H 2 -Ar atmosphere can be retarded by pulsed direct current power and the discharge current dropped greatly. The growth of boride layer was slower than that of conventional bonding and, in addition, the hardness was lower.

Nickel mesh, as one of the most efficient electromagnetic interference (EMI) shielding materials, has been widely adopted in electronic devices such as plasma display panel (PDP). In this study, the nickel mesh sheet was continuously produced in industrial scale by a unique electrochemical process and which microstructure was analyzed by small-angle neutron scattering and field-emission scanning electron microscopy. The precision nickel mesh sheet was well formed by continuous electro-forming equipment with a rotating patterned cathode, soluble/insoluble anode and multiple stage of rolling wheels. Neutron diffraction analysis and morphology observation showed that the nickel mesh formed by electro-deposition process has less defects for industrial applications.

Tantalum oxide (Ta2O5) thin films were sputtered onto MOS structural diodes and MOS-FETs with Si wafer substrates by a number of methods, including RF reactive sputtering, RF reactive magnetron sputtering and ion beam sputtering, and the plasma-induced damage was evaluated by means of changes in flat-band potential in measurement of the capacitance-voltage (C-V) in the case of MOS diodes, and the change in transistor parameters in the case of MOS-FETs.(1) The most severe plasma-induced MOS damage occurred under ordinary RF sputtering conditions. The use of ion beam sputtering reduced the plasma-induced MOS damage compared from that in reactive RF sputtering.(2) The as-sputtered Ta2O5 films were all in amorphous structure with crystallization temperatures of about 730°C.

Ni-P alloys were electrodeposited using simple chloride baths containing 0 to 0.24 mol/L of phosphorus acids (H3PO2, H3PO3 and H3PO4). In the case of baths containing H3PO4, pure Ni was plated with hydrogen gas evolution, while the H3PO2 and H3PO3 baths yielded the corresponding Ni-P alloy at various current efficiencies and with a phosphorus content of 0 to 17 weight percent. As a result of electrochemical experiments and thermodynamic analysis involving the Gibb's free energy change in the deposition process, equations (1)-(3) were developed for alloy deposition in the phosphorous acid baths.2H++2e-→H2……(1)Ni2++2e-→Ni……(2)3Ni2++H3PO3+3H+6e-→Ni3P+3H2O……(3)The calculated values of the Gibb's free energy change for equation (3) showed that the induced co-deposition mechanism with phosphorus and nickel metal was reasonably explained by the strong atomic interaction between Ni and P.

Summary form only given, as follows. Diamond-like carbon(DLC) films are of considerable research interests because of their widespread applications as protective coatings in areas such as magnetic storage disks, biomaterial coatings and as micro-electromechanical devices(MEMs). Although DLC films have been considered as a strong candidate for various applications due to its excellent mechanical properties, their poor adhesion on tool steels limits the applications. In order to overcome this drawback, some ideas were introduced. Recently, ion implantation was used to improve the adhesion between thin film and substrate. In this work, we investigated effect of ion implantation on the adhesion strength of DLC film as a function of ion doses and implanted energies. Ti and W ions were implanted on the Si-wafer and WC-Co substrates, then DLC films were deposited by ion beam deposition method. A CSEM-REVETEST scratch tester was used to assess the adhesion characteristics. From results, the adhesion strength of films was improved as increasing ion implantation energy, however there was no significant change with ion dose. Further results, including morphology and compositional variation at the different ion energies and doses, will be presented.

Summary form only given, as follows. Summary form only given. Hard chromium electroplating had contributed much to industry over 50 years before the environmental problem of hexavalent chrome has arisen. Many researches related with hexavalent chromium replacement have been conducted according to extension of awareness about such an environmental problem. Among these studies, an investigation has been undertaken by nitrogen plasma ion implantation and pulsed plasma process to develop the novel process as an alternative to hexavalent chromium electroplating. In this study, Cr plating from trivalency chrome bath was conducted, followed by the plasma ion implantation (PIII) treatment to improve mechanical properties of the trivalency chrome plated films. Nitrogen ion implantation was conducted onto a Cr plating layer under the conditions of several implantation doses and implantation energies. The films were characterized by optical microscopy, RBS and nanoindentator. From the results, color of film surface after ion implantation was changed to gray, and number of cracks in the trivalency chrome plated layer increased. XRD analysis of the films indicated the formation of hard compound layer of chromium-nitride. The surface hardness was improved from 13 to 17 GPa and projected range (implantation depth) of nitrogen ions in the film was 30 nm. The detailed results will be presented.

The effect of ion mass and charge state on plasma transport through a 90/spl deg/-curved magnetic filter is experimentally investigated using a pulsed cathodic arc source. Graphite, copper, and tungsten were selected as test materials. The filter was a bent copper coil biased via the voltage drop across a low-ohm, "self-bias" resistor. Ion transport is accomplished via a guiding electric field, whose potential forms a "trough" shaped by the magnetic guiding field of the filter coil. Evaluation was done by measuring the filtered ion current and determination of the particle system coefficient, which can be defined as the ratio of filtered ion current, divided by the mean ion charge state, to the arc current. It was found that the ion current and particle system coefficient decreased as the mass-to-charge ratio of ions increased. This result can be qualitatively interpreted by a very simple model of ion transport that is based on compensation of the centrifugal force by the electric force associated with the guiding potential trough.

Oxide films were grown on pure cobalt and on three alloys, Co5Mn, Co5Ni and Co5Ti at 950°C for various times to produce several thicknesses. The solar absorptance was found to increase with film thickness and saturate at about 0.83–0.85. This value agreed very well with the one calculated from the index of refraction. Emittances were below 0.10 for films of about 1 μm in thickness. Rather high values of the absorptance-to-emittance ratio of 10 or greater were obtained for this films. Emittances were observed also to increase with film thickness, and the ratio of absorptance to emittance decreased to about 5 at film thicknesses of 4 μm. SEM examination of the surface showed that no surface asperities existed, and thus multiple reflections were not obtained. An analysis of the defect structures of CoO and doping effects on the defect structure showed that the introduction of impurity bands or of changes in the cation vacancy concentration did not play a role in determining the optical properties. The “plasma wavelength” calculated from the band gap energy, based on Christie's theory, did not correlate with spectral reflectance curves.

Summary form only given, as follows. Curved magnetic filters are commonly used with cathodic vacuum arcs to remove macroparticles from the plasma stream. Such filtering is necessary for high quality of coatings for semiconductor and optical applications. It is known that biasing the filter positively improves plasma throughput and thus deposition rate. For systems operating with pulsed arcs and open filters, it is practical and economical to use the arc current for generation of magnetic filter field. This approach eliminates the need for a magnet supply and also reduces the overall power consumption and cooling needs. This solution has the additional advantage that higher currents can be utilized than one would use for DC systems, and higher currents can be advantageous for obtaining highest system coefficients. There was, however, no means to supply bias to the filter due to the fact that the bias capacitor couples to the pulse forming network of the arc supply. In this study, self-bias was introduced using a low-ohm resistor between the anode of the arc source and the filter entrance. Experiments confirm that bias of pulsed filters can been realized simply by using the voltage drop across a self-bias resistor.