Coating Methods Used in UV and EB Technology

Hydroxyapatite has become an important coating material for bioimplants, following the introduction of synthetic HAp in the 1950s. The HAp coatings require controlled surface roughness/porosity, adequate corrosion resistance and need to show favorable tribological behavior. The deposition rate must be sufficiently fast and the coating technique needs to be applied at different scales on substrates having a diverse structure, composition, size, and shape. A detailed overview of dry and wet coating methods is given. The benefits of electrodeposition include controlled thickness and morphology, ability to coat a wide range of component size/shape and ease of industrial processing. Pulsed current and potential techniques have provided denser and more uniform coatings on different metallic materials/implants. The mechanism of HAp electrodeposition is considered and the effect of operational variables on deposit properties is highlighted. The most recent progress in the field is critically reviewed. Developments in mineral substituted and included particle, composite HAp coatings, including those reinforced by metallic, ceramic and polymeric particles; carbon nanotubes, modified graphenes, chitosan, and heparin, are considered in detail. Technical challenges which deserve further research are identified and a forward look in the field of the electrodeposited HAp coatings is taken.

Download Full-text

Advances in MXene Films: Synthesis, Assembly, and Applications

Transactions of Tianjin University ◽

10.1007/s12209-021-00282-y ◽

2021 ◽

Author(s):

Xiaohua Li ◽

Feitian Ran ◽

Fan Yang ◽

Jun Long ◽

Lu Shao

Keyword(s):

Spin Coating ◽

Reaction Mechanisms ◽

Membrane Separation ◽

Synthesis Methods ◽

Metal Carbides ◽

Max Phases ◽

Practical Applications ◽

Coating Methods ◽

And Performance ◽

Important Form

AbstractA growing family of two-dimensional (2D) transition metal carbides or nitrides, known as MXenes, have received increasing attention because of their unique properties, such as metallic conductivity and good hydrophilicity. The studies on MXenes have been widely pursued, given the composition diversity of the parent MAX phases. This review focuses on MXene films, an important form of MXene-based materials for practical applications. We summarized the synthesis methods of MXenes, focusing on emerging synthesis strategies and reaction mechanisms. The advanced assembly technologies of MXene films, including vacuum-assisted filtration, spin-coating methods, and several other approaches, were then highlighted. Finally, recent progress in the applications of MXene films in electrochemical energy storage, membrane separation, electromagnetic shielding fields, and burgeoning areas, as well as the correlation between compositions, architecture, and performance, was discussed.

Download Full-text

Review on stationary phases and coating methods of MEMs gas chromatography columns

Reviews in Analytical Chemistry ◽

10.1515/revac-2020-0102 ◽

2020 ◽

Vol 39 (1) ◽

pp. 247-259

Author(s):

Liu Yang ◽

Molin Qin ◽

Junchao Yang ◽

Genwei Zhang ◽

Jiana Wei

Keyword(s):

Gas Chromatography ◽

Microelectromechanical Systems ◽

Stationary Phases ◽

Preparation Methods ◽

Site Analysis ◽

Advantages And Disadvantages ◽

Coating Methods ◽

On Line ◽

Inorganic Adsorbents ◽

Gas Chromatography Columns

Abstract Gas chromatography (GC) is an important and widely used technique for separation and analysis in the field of analytical chemistry. Micro gas chromatography has been developed in response to the requirement for on-line analysis and on-site analysis. At the core of micro gas chromatography, microelectromechanical systems (MEMs) have the advantages of small size and low power consumption. This article introduces the stationary phases of micro columns in recent years, including polymer, carbon materials, silica, gold nanoparticles, inorganic adsorbents and ionic liquids. Preparation techniques ranging from classical coating to unusual sputtering of stationary phases are reviewed. The advantages and disadvantages of different preparation methods are analyzed. The paper introduces the separation characteristics and application progress of MEMs columns and discusses possible developments.

Download Full-text

Introduction of Chalcogenide Glasses to Additive Manufacturing: Nanoparticle Ink Formulation, Inkjet Printing, and Phase Change Devices Fabrication

Scientific Reports ◽

10.1038/s41598-021-93515-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

A. Ahmed Simon ◽

B. Badamchi ◽

H. Subbaraman ◽

Y. Sakaguchi ◽

L. Jones ◽

...

Keyword(s):

Thin Films ◽

Phase Change ◽

Inkjet Printing ◽

Chalcogenide Glasses ◽

Dip Coating ◽

Potential Applications ◽

Coating Methods ◽

Report Data ◽

Nanoparticle Ink ◽

Ink Formulation

AbstractChalcogenide glasses are one of the most versatile materials that have been widely researched because of their flexible optical, chemical, electronic, and phase change properties. Their application is usually in the form of thin films, which work as active layers in sensors and memory devices. In this work, we investigate the formulation of nanoparticle ink of Ge–Se chalcogenide glasses and its potential applications. The process steps reported in this work describe nanoparticle ink formulation from chalcogenide glasses, its application via inkjet printing and dip-coating methods and sintering to manufacture phase change devices. We report data regarding nanoparticle production by ball milling and ultrasonication along with the essential characteristics of the formed inks, like contact angle and viscosity. The printed chalcogenide glass films were characterized by Raman spectroscopy, X-ray diffraction, energy dispersive spectroscopy and atomic force microscopy. The printed films exhibited similar compositional, structural, electronic and optical properties as the thermally evaporated thin films. The crystallization processes of the printed films are discussed compared to those obtained by vacuum thermal deposition. We demonstrate the formation of printed thin films using nanoparticle inks, low-temperature sintering and proof for the first time, their application in electronic and photonic temperature sensors utilizing their phase change property. This work adds chalcogenide glasses to the list of inkjet printable materials, thus offering an easy way to form arbitrary device structures for optical and electronic applications.

Download Full-text

Atomic Layer Deposition Coated Filters in Catalytic Filtration of Gasification Gas

Catalysts ◽

10.3390/catal11060688 ◽

2021 ◽

Vol 11 (6) ◽

pp. 688

Author(s):

Tyko Viertiö ◽

Viivi Kivelä ◽

Matti Putkonen ◽

Johanna Kihlman ◽

Pekka Simell

Keyword(s):

Atomic Layer ◽

Biomass Gasification ◽

Optimal Conditions ◽

Al2o3 Layer ◽

Gas Cleaning ◽

Catalytic Coating ◽

Layer Deposition ◽

Coating Methods ◽

Tar Reforming ◽

Stop Flow

Steel filter discs were catalytically activated by ALD, using a coating of supporting Al2O3 layer and an active NiO layer for gas cleaning. Prepared discs were tested for model biomass gasification and gas catalytic filtration to reduce or eliminate the need for a separate reforming unit for gasification gas tars and lighter hydrocarbons. Two different coating methods were tested. The method utilizing the stop-flow setting was shown to be the most suitable for the preparation of active and durable catalytic filters, which significantly decreases the amount of tar compounds in gasification gas. A pressure of 5 bar and temperatures of over 850 °C are required for efficient tar reforming. In optimal conditions, applying catalytic coating to the filter resulted in a seven-fold naphthalene conversion increase from 7% to 49%.

Download Full-text