Additive-free hot-pressed silicon carbide ceramics-A material with exceptional mechanical properties

Additive-free hot-pressed silicon carbide ceramics-A material with exceptional mechanical properties

P. Šajgalík, J. Sedláček, Z. Lenčéš, J. Dusza, H.-T. Lin

Abstract

Densification of silicon carbide without any sintering aids by hot-pressing and rapid hot pressing was investigated. Full density (>99% t.d.) has been reached at 1850 °C, a temperature of at least 150–200 °C lower compared to the up to now known solid state sintered silicon carbide powders. Silicon carbide was freeze granulated and heat treated prior the densification. Evolution of microstructure, mechanical properties and creep behavior were evaluated and compared to reference ceramics from as received silicon carbide powder as well as those of commercial one. Novel method results in dense ceramics with Vickers hardness and indentation fracture toughness of 29.0 GPa and 5.25 MPa m1/2, respectively. Moreover, the creep rate of 3.8 × 10−9 s−1 at 1450 °C and the load of 100 MPa is comparable to the commercial α-SiC solid state sintered at 2150 °C.

Keywords

Silicon carbide, Hot pressing, Microstructure, Mechanical properties, Creep resistance, freeze granulation

Fabrication and optical studies of transparent Tm, Ho:YAG ceramics

Fabrication and optical studies of transparent Tm, Ho:YAG ceramics

Agata Sidorowicz, Magdalena Nakielska, Anna Wajler, Helena Węglarz, Katarzyna Jach, Andrzej Olszyna

Abstract

The aim of this work has been to obtain transparent Tm, Ho:YAG ceramics (thulium doping range: 2–6 at.%, holmium doping range: 0.1–1.0 at.%) by reaction sintering using commercial powders. It has been proved that the particle size, purity and degree of agglomeration of the powders used are crucial from the point of view of the optical quality of ceramics. The spectroscopic measurements of Tm, Ho:YAG ceramics with different concentration of active ions (including transmission and emission spectra measurements) have been presented and discussed. As has been found, both concentration of holmium and thulium separately as well as the balance between them are of great importance. Energy transfer between Tm and Ho ions has been demonstrated.

Yttrium aluminum garnet, Transparent ceramic, Tm, Ho:YAG, Freeze Granulation, Reactive sintering.

—-

Please contact us and we will further discuss the opportunities with Freeze Granulation on your powder system and read more on technology and we propose a Granulation Test of your powder system.

Second day at CERAMITEC 2015

Second day at CERAMITEC 2015 on Oct 21th with good discussions upon processing of different powder material by Freeze Granulation and the advantages regarding granule homogeneity and the impact on the ultimate material performance it brings.

Please contact us and we will further discuss the opportunities with Freeze Granulation on your powder system and read more on technology and we propose a Granulation Test of your powder system.

Second day at CERAMITEC 2015 Second day at CERAMITEC 2015-1 Second day at CERAMITEC 2015-2

Granulation techniques and technologies: recent progresses

Granulation techniques and technologies: recent progresses

Srinivasan Shanmugam

Pharm. R&D Institute, Hanmi Pharm. Co., Ltd., Hwasung, Gyeonggi, Korea

Abstract

Granulation, the process of particle enlargement by agglomeration technique, is one of the most significant unit operations in the production of pharmaceutical dosage forms, mostly tablets and capsules. Granulation process transforms fine powders into free-flowing, dustfree granules that are easy to compress. Nevertheless, granulation poses numerous challenges due to high quality requirement of the formed granules in terms of content uniformity and physicochemical properties such as granule size, bulk density, porosity, hardness, moisture, compressibility, etc. together with physical and chemical stability of the drug. Granulation process can be divided into two types: wet granulation that utilize a liquid in the process and dry granulation that requires no liquid. The type of process selection requires thorough knowledge of physicochemical properties of the drug, excipients, required flow and release properties, to name a few. Among currently available technologies, spray drying, roller compaction, high shear mixing, and fluid bed granulation are worth of note. Like any other scientific field, pharmaceutical granulation technology also continues to change, and arrival of novel and innovative technologies are inevitable. This review focuses on the recent progress in the granulation techniques and technologies such as pneumatic dry granulation, reverse wet granulation, steam granulation, moisture-activated dry granulation, thermal adhesion granulation, freeze granulation, and foamed binder or foam granulation. This review gives an overview of these with a short description about each development along with its significance and limitations.

—-

Please contact us and we will further discuss the opportunities with Freeze Granulation in your powder system and read more on technology.

Synthesis of Li-ion battery cathode materials via freeze granulation

Keivan Amiri Kasvayee
Department of Materials and Manufacturing Technology
Chalmers University of Technology

Göteborg, Sweden

Synthesis of Li-ion battery cathode materials via freeze granulation

Summary

Recently, enormous efforts have been done within the development of Li-ion batteries for use in portable electric devices from small scale applications such as mobile phones, digital cameras, laptop computers, to large scale applications like electrical vehicles (EVs) and hybrid electric vehicles (HEVs). LiFePO4 as an active material in cathode materials in Li-ion batteries has shown outstanding advantages compare to other cathode materials such as low cost, low toxicity and environmental compatibility, good thermal stability, high theoretical specific capacity of 170 mAh/g and operating reversibility at 3.4V. Still, it is a need to develop the manufacture of the cathode material to achieve improved performance reliability by using  environmental sustainable processes in order to meet future demands in large scale production and uses of Li-ion batteries.
The aim of this work was to develop a non-toxic, cheap, efficient and environmentally friendly process for synthesis of high quality active cathode material based on LiFePO4 for Li-ion batteries. Water based suspensions/solutions containing various reactant constituents have been homogenized, granulated and calcined. Freeze granulation was applied as the key tool for the synthesis of LiFePO4 with integrated carbon in order to produce granules with high degree of homogeneity prior to calcination. The resulting powder materials have been evaluated by XRD, carbon and conductivity measurements and characterization of other physical properties such as density and specific surface area. The promising version was used for manufacture of cathode material by tape casting, cell assembling and evaluation of the performance by charge/discharge cycling of the cells.
For the best sample in our experiment the XRD results revealed a high degree of purity, homogeneity and crystallinity of LiFePO4. The produced LiFePO4/C composite also had a high specific surface area and, therefore, considered as a promising material for cathode manufacturing and cell assembly. A discharge capacity of 155 and 140 mAh/g was achieved at the fifth cycle at 0.1C rate at room temperature for the cathodes which were made with NMP (solvent based) and water system, respectively. The long-term stability test indicated good result with no loss in capacity for at least 390 cycles. The satisfactory discharge capacity should be attributed to the homogenous nano-sized particles with a conductive porous carbon structure that was provided by the freeze granulation process and adapted calcination process.

Keywords: Li-ion batteries, LiFePO4, cathode active material, specific capacity, freeze
granulation, calcination, LiFePO4/C composite, cell assembly.

Please contact us and we will further discuss the opportunities with Freeze Granulation in your powder system and read more on technology.

Freeze Granulation: A novel technique for low-loss Mn-Zn ferrites

Vasiliki Tsakaloudi, George Kogias, Vassilios Zaspalis

Laboratory of Inorganic Materials, Chemical Process Engineering Research Institute,
Centre for Research and Technology-Hellas, 57001 Thermi-Thessaloniki, Greece

Freeze Granulation – A novel technique for low-loss Mn-Zn ferrites

In the present study the freeze granulation technique is applied in the manufacturing process of Mn-Zn power ferrites. The powders are prepared by the solid state reaction method and a comparison between the standard industrially used spray-drying method and the freeze granulation process with subsequent freeze drying has been carried out, in terms of granulate morphology, compaction behavior and pore size distribution, sintering behavior and magnetic performance. It apeared that the freeze granulation process enables the formation of homogeneous green compact microstructures and finally leads to sintered products of good magnetic quality. Consequently, Mn-Zn ferrites with low losses of 287 mW/cm3 (at measuring conditions f=100 kHz, B=200 mT and T=1000C) are manufactured. 

Please contact us and we will further discuss the opportunities with Freeze Granulation in your powder system and read more on technology.

Recent advances in granulation technology

Himanshu.K.Solanki, Tarashankar Basuri, Jalaram H.Thakkar, Chirag A. Patel
Department of Pharmacy, SSR College of Pharmacy, Sayli-silvassa Road, Sayli, UT of D& NH-396230, India.

RECENT ADVANCES IN GRANULATION TECHNOLOGY

Granulation is one of the most important unit operations in the production of pharmaceutical oral dosage forms. Granulation
process will improve flow and compression characteristics, reduce segregation, improve content uniformity, and eliminate excessive amounts of fine particles. The results will be improved yields, reduced tablet defects, increased productivity, and reduced down time. Pharmaceutical products are processed all over the world using the direct-compressing, wet-granulation, or dry granulation methods. Which method is chosen depends on the ingredients individual characteristics and ability to properly flow, compresses, eject, and disintegrate. Choosing a method requires thorough investigation of each ingredient in the formula, the combination of ingredients, and how they work with each other. Then the proper granulation process can be applied. The objective of present article was to focus on the novel granulation technology.

Keywords: Pneumatic Dry Granulation, Freeze granulation, Moisture activated dry granulation, Foam granulation, Steam
granulation, Thermal Adhesion Granulation

Please contact us and we will further discuss the opportunities with Freeze Granulation in your powder system and read more on technology.

Illustration of Freeze Granulation
Illustration of Freeze Granulation

ECerS XIII Conference – Limoges, France

ECerS XIII Conference – Limoges, France
ECerS XIII Conference – Limoges, France

ECerS XIII Conference – Limoges, France – Welcome to PowderPro’s stand No 1 at the exhibition at ECerS XIII Conference (European Ceramic Society) in Limoges, France from the 23rd to the 27th of June 2013. We look forward to meet customers, partners and new contacts for interesting discussions in our stand!

We plan to have our equipment available at a nearby lab for you to see the process of Freeze Granulation.

Please contact us and we will further discuss the opportunities with Freeze Granulation in your powder system and read more on technology and a Granulation Test of your powder system.

Freeze Granulation of Nanomaterials on Slideshare

Please see our presentation Freeze Granulation of Nanomaterials on Slideshare.

How Freeze Granulation can improve the homogeneity of your nanomaterials and make it possible to redisperse a nanomaterial that have been dried.

Please contact us and we will further discuss the opportunities with Freeze Granulation in your powder system and read more on technology and a Granulation Test of your powder system.