Thin films of GaN and its alloy AlGaN are investigated with respect to their properties of the persistent photoconductivity (PPC). In this work, we show that the film-substrate interface plays an important role for the metastable electrical effect. Strongly absorbed bandgap light causes an increase of photoconductivity which is about one order of magnitude higher when the sample is illuminated ...

Surface treatments of engineering materials are important for serviceable engineering components. One of the thermo-chemical surface treatments of steel based materials is the boriding process. In this study, low alloy steel substrates were borided by pack boriding process at 900 C. Experimental indentation tests were conducted on Dynamic Ultra-micro Hardness test machine, under applied peak lo...

t is known that the protective value of zinc is partially a result of its ability to form a protective film when plated on a base metal, such as steel. The zinc is sacrificial and corrodes I preferentially to protectthe steel. Although pure zinc coating provides some degree of protection for the substrate, in a severe corrosion environment, zinc is consumed rapidly. For this reason, it is usual...

The structure and physical-mechanical properties of Ti-Ni-Ta-based surface alloy synthesized on the TiNi-substrate through additive thin-film electron-beam method have been studied. synthesis was carried out by 30-fold alternation operations deposition a dopant film (Ti 60 Ta 40 (at.%), ~50 nm thick) liquid-phase mixing film/substrate using pulsed low-energy high-current electron beam. It found...

The formation of alloys by adsorbing gold on a Pd(111) single crystal substrate and subsequently annealing to various temperatures is studied in an ultrahigh vacuum by means of Auger and X-ray photoelectron spectroscopy. The nature of the alloy surface is probed by CO chemisorption using temperature-programmed desorption and reflection-absorption infrared spectroscopy. It is found that gold gro...

magnesium alloys as biodegradable materials can be used in body as an implant materials but since they have poor corrosion resistance, it is required to decrease their corrosion rate by biocompatible coatings. in this study, hydroxyapatite (ha) coatings in the presence of an intermediate layer of zrn as a biocompatible material, deposited on az91 magnesium alloy by ion beam sputtering method at...

Three types of inexpensive Pb-free solder joints, namely Zn-based and Bi-based solders, and a CuSn alloy were studied for application to the high-temperature operation of wide band-gap power semiconductor devices using GaN or SiC. Zn– Al solder sheets, whose melting point is 380°C were prepared, and then surface oxides were removed by RF plasma etching. Subsequently, Cu thin films were deposite...

In this study the bioactivity of hydroxyapatite/poly(ε-caprolactone)–poly(ethylene glycol) bilayer coatings on Nitinol superelastic alloy was investigated. The surface of Nitinol alloy was activated by a thermo-chemical treatment and hydroxyapatite coating was electrodeposited on the alloy, followed by applying the polymer coating. The surface morphology of coatings was studied using FE-SEM and...

Electrochemical depositions of calcium phosphate (Ca-P) film on NiTi alloy in concentrated simulated body flood (SBF×5) were carried out by cathodic polarization. The Ca-P layer was successfully deposited on Ni-Ti alloy substrate under 10mA/cm2 current density for 2 hours at room temperature. Then, in order to investigate the bioactivity of the pre-calcified samples, they were immersed in SBF f...

The contact angle between molten Fe-Al alloy with 0.03, 0.3, and 3 mass% Al composition, Y2O3 matrix oxide substrate 0.002, 0.32, 1 SiO2 activity was measured using sessile drop method in Ar atmosphere at 1873 K, the interfacial tension evaluated. Fe-0.3 Y2Si2O7 + (aSiO2 = 1) decreased over time during 60 s after dropped onto substrate. decrease of 20°, that 628 mN・m−1 Conversely, other angles ...