Recent Patents on Materials Science - Volume 8, Issue 1, 2015

In this review article, we are mainly focused on discussion and analysis of techniques reported in patents and studies in the field of CO2 capture and sequestration from atmospheric air and flue gases with the use of pure Ca(OH)2 dispersions and Ca(OH)2-comprising sorbents. The discussed CO2 capture techniques are classified in terms of the composition of Ca(OH)2-comprising sorbents. The physicochemical aspects of the carbonation process of Ca(OH)2 dispersions are discussed and analyzed as well.

Proton exchange membrane (PEM) fuel cell receives special attention as an alternative power device for various industrial applications because of its excellent energy conversion efficiency, high power density, low operating temperature, convenient fuel supply, longer life time and low emission. The prospective commercial applications of PEM fuel cell comprise laptop, computers, cellular phones, military back power packs, scooters, cars, etc. However, the high production cost and long term durability hinder the commercialization of PEM fuel cell. Bipolar plate is the essential constituent of PEM fuel cell, as it contributes to 80% of weight and 40% of total cost in a PEM fuel cell. Also, it facilitates many important functions; such as: supplies reactant gases at anode and cathode, connects individual cells electrically to form cell stack, and removes the unwanted products away from the cell. Hence, widespread commercialization of PEM fuel cell technology is highly dependent on the performance and cost of the bipolar plates. Primarily, bipolar plates are fabricated using graphite and metallic materials. But, weak mechanical properties of high density graphite and corrosive nature of metals makes these materials highly unsuitable to be used as bipolar plate in PEM fuel cell. However, new class of materials, such as: coated metals and carbon/ polymer composites have received special attention due to their low fabrication cost, light weight and chemical stability. The bipolar plate materials must satisfy the target values set by the Department of Energy (DOE) of the United States. In this review, article several patents and research articles on various kinds of bipolar plate materials for PEM fuel cell application are discussed in detail.

In this contribution, patents and literature concerning the development and application of tool materials and coating materials are reviewed including patents relating to the selection and preparation of materials for recent lathe-type tools. To address the needs of machining in the future, new types of coating materials and patents dealing with coating methods such as PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition) are described as well, designed to improve the tool wear resistance. It is self-evident that advanced cutting tools are vital for the machining process as the materials and coatings determine their performance. Among various tool materials introduced in this article, the preparation and field of application focus on sintered carbides, ceramics and superhard materials. In addition, the wear process of CBN tools during machining of 100Cr6 steel is used as an example. The results are as follows. In the beginning, with increasing time, the flank wear form shows a regular variation. However, irregular changes occur beyond 50min. Moreover, the wear process of the tool consists initially in formation of small pits by tool friction, and subsequently by flank wear as described above. Furthermore, research results will be described concerning the influence of thermal exposure during machining on coated tools. Finally, the wear state of coated and non-coated tools subjected to the same machining conditions are being compared, using white-light interferometry and scanning electron microscopy in conjunction with energydispersive X-ray spectroscopy (EDS). The results imply that research and development into cutting tool coatings are vital not only to obtain longer tool service life, but also to guarantee high-quality machined surfaces.

Recently, many patents have been developed for developing the measuring methods of grinding temperature. Some of them could measure temperature of grinding zones more accurately, which enables to control thermal damage of work piece and wear of grinding wheel effectively. Among these patents, one is for a grinding temperature measurement based on inverse heat conduction problem. It inlays a piece of thin film with low and stable melting point between two work pieces. The thin film will be melted by grinding heat generated by work piece ground. Temperature at certain depth could be calculated from the melted depth and melting point of the thin film. On this basis, grinding temperature will be calculated by solving the inverse heat conduction problem. Based on researches of grinding temperature measurement, this paper introduced research status of grinding temperature measurement and classified and summarized measuring methods. Currently, measuring methods of grinding temperature could be divided into direct contact measurement and non-contact measurement. Direct contact measurement includes the coating technique and thermocouple temperature measurement. Thermocouple temperature measurement can be further divided into open-top approach and clip-on approach (including artificial thermocouple and semi-artificial thermocouple). The non-contact measurement includes infrared thermal imaging, fiber-optical infrared temperature measurement, infrared radiation temperature measurement and two-color infrared temperature measurement. Working principles, characteristics and application ranges of these measuring methods were discussed and compared in this paper.

It is well known that a naturally matured loofah has some distinct inherent properties including extremely low density and high absorbability, due to its unique fibrous microstructure and macro-cellular architecture including the spatial configuration of voids and solids. In this paper, we focus on patents and literature related to the development of a three-dimensional (3D) lightweight metallic structure by means of a design bio-inspired by the cellular architecture of a fully ripe loofah. To simplify the design, the cellular architecture of the loofah is assumed to be a two-layered open-cell foam structure, and each layer is a porous shell wall. The two layers are connected by three porous radial plates. With this simplification, a lightweight metallic structure with hexagonal pores is developed that achieves the desired balance of weight and mechanical properties. The resulting metallic structure has low density (190.39 kilograms per cubic meter) and the Young’s modulus is estimated by compressive testing using a finite element technique.

In order to study excellent properties of the magnetorheological fluids (MRFs), some relevant patents and researches are studied. Experiment materials, experimental method and test methods are elaborated, and two types of carriers are used to prepare MRFs samples with different additives addition. The microstructures of both uncoated magnetic particles and coated magnetic particles are observed by scanning electron microscope (SEM). The properties of these samples including sedimentation stability, zero field viscosity and shear yield stress are tested and analyzed. Experimental results show that MRFs with mineral oil 350N as their carrier liquid are better than dimethyl silicone oil; Organic Bentonite and TM-618 can improve the sedimentation stability and shear yield stress of MRFs. Moreover, they have influence on zero field viscosity and MRFs with Organic Bentonite 3% and TM-618 3.5% have good overall properties.