Recent Patents on Materials Science - Volume 8, Issue 2, 2015

Due to attractive surface properties and to intrinsic brittleness of Complex Metallic Alloys (CMAs), most of their potential applications involve materials with high surface-to-volume ratios, including thin films and coatings. While physical vapor deposition techniques are efficient for the processing of CMA films on line-of-sight surfaces, chemical vapor deposition (CVD) is well positioned for their application on complex surfaces. However, for CVD process to be implemented efficiently in the processing of CMA films a number of challenges must be addressed. Because numerous CVD reagents, commonly called precursors, are low vapor pressure liquids or solids, one of these challenges is the production of vapors of such precursors, which are decomposed in the deposition chamber to provide the desired film. Such a production has to be ensured at high rate and must be reproducible and stable during the whole process. Actual solutions to this question involve (i) bubbling inert gas through thermally regulated liquid precursors, (ii) leaching the surface of fixed precursor powder beds, and (iii) in situ generating the precursor flow by passing a reactive gas through a thermally regulated bed of the metallic element to be transported. Such solutions neither may be satisfactory for actual R&D needs nor may be transferable to industrial environments. These reasons are in part responsible for the limited implementation of advanced materials (including CMA-based ones) in numerous industrial and hence societal needs. More recently, innovative solutions have been proposed to feed deposition systems based on vapor phase chemical techniques (CVD and Atomic Layer Deposition, ALD). Such solutions are Direct Liquid Injection (DLI) of dissolved solid precursors and also sublimation of the latter in fluidized beds or in elaborated fixed beds. Such technological responses show promise for industrial applications of CVD, especially for the deposition of metals and ceramic compounds for which the available molecular and inorganic precursors present low vapor pressures. This review provides an overview of the methods by which precursor vapors are transported to the deposition chamber. Early and recent patents dedicated to such technologies will be revisited and considered in the light of the deposition of multimetallic alloy coatings.

Recognizing quasicrystals that are embedded in Al-based cast alloys is a challenging task. For this reason, we synthesized a series of multi-component, AlMn-based alloys that contain many icosahedral quasicrystals in addition to crystalline phases. We then conducted a thorough investigation in order to unambiguously distinguish the quasicrystalline phases from all the others. Numerous modern analytical techniques were employed for this, and our efforts proved to be successful. As a result, our newly developed, particle-extraction and surface-etching procedure has been successfully patented.

A concept of thermal storage of digital information in a thermal memory cell as described in the patent “Method for storing digital information and storage element” (EP2207177) is presented, where a byte of digital information can be stored into the storage medium by pure thermal manipulation, in the absence of an electric or a magnetic field. Thermal inscription of information employs a specific temperature-time profile that involves continuous cooling and isothermal waiting (aging) time periods. The employed storage media were magnetically frustrated metallic solids. We succeeded to thermally write arbitrary ASCII characters into the Taylor-phase T-Al3(Mn,Fe) complex intermetallic compound and the Cu-Mn canonical spin glass.

This manuscript presents our patent for a more effective magnetocaloric material based on Gd5Si2Ge2 as well as its method of production. The material has high refrigeration capacities and, with modifications to its composition, it is possible to control the temperature at which its magnetocaloric effect is the largest. This effect was achieved by modifying the stoichiometry of the starting composition. First, the Si or Ge is replaced with Fe in the starting composition; then, there is an additional heat treatment and quenching of the alloy. This produces a novel microstructure and a magnetocaloric material with an enhanced refrigeration capacity. Although the magnetocaloric effect is slightly reduced as a result of this process, the iron indirectly affects the microstructure and thereby reduces the hysteresis losses that occur during the first-order structural transformation. Hysteresis losses, of course, have a very detrimental effect on the refrigeration capacity. We observe that even a small amount of iron increases the refrigeration capacity up to 12%. Furthermore, by changing the amount of iron, we can alter the temperature at which the magnetocaloric effect is the largest. This then increases the temperature range over which this material can be applied. The patent covers the process for improving the usefulness of magnetocaloric Gd5Si2Ge2-based alloys as a working material for a magnetocaloricbased refrigerator. These refrigerators are energetically more efficient and environmentally less harmful than regular compressor-based refrigerators.

This review summaries recent patents on catalysts dealing with quasicrystal. Icosahedral quasicrystal (iQc) Al-Cu-Fe has been studied in terms of catalysis. The Al63Cu25Fe12 iQc (i-AlCuFe) is a promising precursor for Cu catalysts, whose constituent elements, compositions and quasi-periodic structure are in favor of processing high performance catalysts. Brittleness resulting from quasi-periodic structure enables one to obtain powder form for processing catalysts. Relatively low dissolution rate of Al due to quasi-periodic structure upon leaching with NaOH solution, generates homogeneous nanocomposite consisting of Fe3O4 and Cu and hence gives rise to high activity and thermal stability for steam reforming of methanol. The catalytic properties of the leached i- AlCuFe are furthermore improved by formation of a spinel CuFe2O4 generated by consequent calcination at 873K in air. In order to understand sole contribution, spinel CuFe2O4 is studied independent of i-AlCuFe. Bulk spinel CuFe2O4 reduced at 633K shows a self-assembled microstructure with fine dispersion of Cu nanoparticles embedded in porous Fe3O4 matrix, accompanied by high catalytic performance. High thermal stability of Cu nanoparticles in the Fe3O4 is ascribed to the immiscible interaction between Cu and Fe, where the Fe3O4 can suppress the sintering of Cu particles.

The development of antimicrobial biomaterials based on silver nanoparticles (SNP) has attracted significant interest during the past decade. SNP have demonstrated very beneficial properties, especially antibacterial, antifungal, anti-viral, and anti-inflammatory properties which can be exploited for a range of technical and medical products, for example topical ointments, bandages, stents. Such applications have been demonstrated to be very effective in the prevention and treatment of bacterial infections. Bacterial infections from medical devices are a major clinical problem and various strategies have been developed to avoid infections via medical device. Consequently, antibiotic coating of devices is of great importance to tackle device-related infection. A large number of studies on SNP as an antimicrobial agent on a range of different medical devices were conducted and related patents for antimicrobial silver based materials disclosed. This article will focus on the very recent patent base for the synthesis and application of silver based materials and devices for medical applications.

We systematically investigated the influence of surfactant on processing PEDOT/PSS thin films by spin-coating technique. As a result, the conductivity of the PEDOT/PSS thin films prepared by the two-step spin-coating method was to be averagely ca. 400Scm-1 which was calculated with sheet resistance and thickness. On the other hand, the conductivity of the PEDOT/PSS thin films prepared by the one-step spin-coating method should be much lower than that of two-step one if assuming that the thickness is the same for the two methods. It is considerable that in the one-step spin-coating method, aggregation of PEDOT/PSS colloidal particles easily occurs before spin-coating, resulting in inhomogeneous coating film. Such inhomogeneous film would show lower conductivity. The two-step spin-coating method can avoid the aggregation and then result in homogeneous film and higher conductivity. Reviews of recent patents on wet-process techniques reported by other research groups are also reported.