Coating

The aim of this study was to coat titanium substrate with bioactive glass nanoparticles and characterize the deposited surface coat. Materials and Methods: Amorphous bioglass nanoparticles < 20 nm in diameter were prepared using a modified sol-gel technique followed by a ball-milling process. The prepared nanoparticles were used to coat airborne particle-abraded titanium disks. The in vitro bioactivity of the bioglass nanopowder was confirmed using simulated body fluid. Coated surfaces were characterized in terms of microstructure, composition, thickness, phase structure, surface roughness, wettability, and tissue behavior in a rabbit model. Results: Bioglass nanoparticles showed apatite formation under a scanning electron microscope (SEM) after 5 days, confirming that bioactivity was enhanced with increasing degradation rate for up to 2 weeks. An optimized deposition technique and heat-treatment process produced a homogenous coating with a uniform thickness of 32 to 39 μm. Chemical analysis confirmed the presence of silicon and calcium on the coated disks. Amorphous coated surfaces exhibited porous nano/microroughness with microcracks and super-hydrophilicity. The interface of the coated disks with subcutaneous tissue revealed good tissue adhesion, high cellular activity, and rich vascularization, with multinucleated cells in the microenvironment surrounding the coat, as confirmed using histomorphometric analysis. Conclusion: The results of this study show that it is feasible to coat titanium surfaces with bioactive glass nanoparticles with super-hydrophilicity and high biologic activity. These particles may promote the regenerative environment around dental implants.

Magnesium (Mg) alloys are light, structural and functional engineering materials with a high strength to weight ratio which are increasingly being used in the automotive, aerospace, and electronic and energy industries. However, magnesium is chemically active with an electrochemistry differing from most conventional engineering metals. This review provided some recent progress of the research on corrosion mechanisms of magnesium and its alloys and a basis for follow on research. Galvanic corrosion, pitting corrosion, intergranular corrosion, filiform corrosion, and crevice corrosion were discussed. Additionally there is a review of coatings for magnesium alloys and an analysis of alloys and coatings. Finally it recommends an option for a future coating that may prove to be the best coating for long lasting corrosion resistant parts.

The present study deals with the objective of coating of needle punched nonwoven fabric with polyurethane (PU) formulation of different coating concentrations for artificial leather effect. The properties of the coated fabrics were evaluated through a number of tests such as breaking strength, abrasion resistance, thickness, GSM, bursting strength, and air permeability. The work reveals that the tensile strength, GSM, bursting strength parameters of the coated fabric got improved as the coating is primarily a function of coating concentration and curing temperature. The coated samples exhibited satisfactory performance properties.

Corrugated metal gaskets made of SUS304 usually have extremely hard layers that contact the flange. Therefore, they must be designed with an outer covering of a softer material. For three-layer gaskets, however, this process is challenging. This paper proposes the coating of corrugated metal gaskets with copper to obtain softer layers and reports on the degree of adhesion of SUS304 with copper. The coating process employs the electroplating method. The results show that there are no cracks or breaches between the metal and copper, and these materials completely enclose SUS304. Cracks also do not occur after the gaskets have been used to seal flange leakage. Furthermore, the copper layers are likely to be durable, showing no changes between before and after use on the flange. The performance of coated corrugated metal gasket was better than standard corrugated metal gaskets.

Coating and lamination are the finish process designed to add or improve specific properties of fabric and it depends on the polymer used and its recipe and also nature of substrate. The polymers used for coating comes in various nature from rigid to flexible according to the requirement. In this project work the polymers used were Thermoplastic polyurethane and poly vinyl chloride and were applied on polyester fabric by hot melt extrusion. Results were investigated for tear strength, Abrasion resistance and flexural rigidity keeping in mind fabrics application. Results suggest that TPU have more tear strength than PVC, also TPU is more abrasion resistant than PVC and more data are shown in the work.

This paper presents the results of research on aluminide protective coatings manufactured on high–temperature creep resistant cast steel. The main purpose of these coatings is protection against the high temperature corrosion, at carburizing and oxidizing potential atmosphere. Coatings were obtained on cast steel type GXNiCrSi 30–18 by slurry cementation in air atmosphere. The tests of carburizing and oxidizing were carried out. The structure of the coatings before and after carburizing and oxidizing is described in the present paper. The chemical composition, thickness and microstructure of coatings were determined. These coatings could protect equipment against hot corrosion at carburizing and oxidizing atmosphere and have thermal shocks resistance.

We developed an engineering model for predicting the active pharmaceutical ingredient (API) content uniformity (CU) for a drug product in which the active is coated onto a core. The model is based on a two-zone mechanistic description of the spray coating process in a perforated coating pan. The relative standard deviation (RSD) of the API CU of the coated tablets was found to be inversely proportional to the square root of the total number of cycles between the spray zone and drying zone that the tablets undergo. The total number of cycles is a function of the number of tablets in the drying zone, the spray zone width, the tablet velocity, the tablet number density, and the total coating time. The sensitivity of the RSD to various critical coating process parameters, such as pan speed, pan load, spray zone width, as well as tablet size and shape was evaluated. Consequently, the critical coating process parameters needed to achieve the desired API CU were determined. Several active film coating experiments at 50, 200, and 400 kg using various pan coaters demonstrated that good correlation between the model predictions and the experimental results for the API CU was achieved. ß

Titanium dioxide (TiO2) due to its high refractive index, is widely used in paint industry as a white pigment. In order to reduce this high cost of TiO2, a part of TiO2 is generally substituted by some other industrial mineral fillers such as calcite and calcined kaolin; however, this substitution affects the quality of paints in terms of stability, coverage (opacity), brightness (gloss), scrub resistance (film toughness), etc. In the present paper, precipitated calcium carbonate (PCC) was substituted for TiO2 in paint mixture at three different pigment volume concentrations (PVC). It was observed that substitution of TiO2 by PCC depends on PVC value at which there is an optimum PCC amount. The quality of paints produced by PCC along with its rheological properties was evaluated based on standard features in both wet and dry paints such as viscosity, density, opacity and gloss values. Addition of PCC increases the opacity to a certain point. Similarly, scrub resistance and viscosity increases with the addition of PCC at all PVCs, however, viscosity is not as much critical for the paint production. On the other hand, there is no any systematic effect of PCC on gloss value of the paint. This study overall demonstrates that PCC can be successfully used to substitute TiO2 only with a careful adjustment of PVC and other extenders used in the paint formulation.

For decades we have hearing that the chemical industry and there also the coating industry, need to break free from its dependency on oil because there are finite resources. Renewable raw materials are constantly under discussion. The paint and coatings industry are focused on innovation and being “green”. Green means a smaller carbon footprint, low VOC content, high renewable content and green processes. The use of renewable ingredients to reduce the carbon footprint, eliminating the use of hazardous materials, introducing biorenewables, incorporating recycled materials, lowering VOC emissions, decreasing energy consumption and reducing waste, while proving it can all be accomplished cost-effectively to become more environmentally responsible. The reduction of environmental damage done by coatings sometimes begins before manufacturing even starts. Research into the carbon footprint of coating materials, or the overall amount of climate-affecting carbon dioxide produced in their manufacture, application, transport and disposal, shows that some coatings simply use fewer resources throughout their life cycles. This paper discusses advances in the use of renewable resources in formulations for various types of coatings. The developments in the application of green and efficient technologies in coating systems are discussed here.

Hot corrosion is a serious problem in boilers, gas turbines, internal combustion engines, and industrial waste incinerators. It consumes the materials at an unpredictably rapid rate. Alloys used at high temperature should possess good mechanical properties, corrosion and oxidation resistance. Thermal spray technology encompasses a group of coating processes that provide functional surfaces to protect or improve the performance of a substrate or component. Many types and forms of materials can be thermal sprayed, Which provide protection from corrosion, wear, and abrasion and for a variety of other applications. The use of protective coatings has been an answer to remedy the lack of high temperature surface stability of metals and alloys in harsh environments. This study is done with the aim of putting together the performance capabilities and applications of alloy and composite coatings.

In this work, three nanoparticles were used to apply seven different coatings
on carbon steel using atomization method (cold spraying) by airbrush to achieve
three types of coating.
The first is single coatings, including Al2O3, SiC and ZrO2 coatings. The
second is binary coatings, including Al2O3 - SiC, Al2O3 - ZrO2 and SiC- ZrO2
coatings. While, the third is Al2O3 - SiC - ZrO2 coating. The characterization of
coated surfaces were investigated by AFM and SEM. All these inspections
indicated the deposition of nanoparticles on carbon steel surface. The thickness of
coated layers were calculated using gravimetric method, while the particle size and
roughness were measured from the analysis of atomic force microscopy.
The thickness of nanoparticle coatings are 6.22160 μm, 0.0781 μm, 1.5504
μm, 0.5145 μm, 3.469 μm, 1.3680 μm , 2.2152 μm for Al2O3, SiC, ZrO2, Al2O3 -
SiC, Al2O3 - ZrO2, SiC- ZrO2, Al2O3 - SiC - ZrO2 respectively. While, the
roughness values are 7.0nm, 26.1nm, 5.44nm, 6.86nm, 8.11nm, 6.64nm, 25.2nm
for Al2O3, SiC, ZrO2, Al2O3 - SiC, Al2O3 - ZrO2, SiC- ZrO2, Al2O3 - SiC - ZrO2
respectively.
Corrosion test was achieved to estimate the corrosion resistance, protection
efficiency and porosity percentage. The corrosion potential shifted to more positive
value for coated surfaces, and the corrosion current density became lower for
coated surfaces. The corrosion rate was decreased.

Dosen Pengampu: Rif'an Fathoni, S.T., M.T BAB I PENDAHULUAN Korosi di lingkungan industry merupakan masalah yang sangat serius karena kerusakan pada peralatan dan kurangnya penanganan korosi yang kurang tepat dapat berakibat fatal seperti terjadinya kebocoran pada suatu alat, ledakan, kebakaran rusaknya lingkungan dan merupakan masalah keamanan serta keselamatan manusia. Fenomena alam dan material khususnya logam mempunyai suatu keterikatan dalam suatu system dan proses. Namun dalam suatu system tersebut terdapat suatu hubungan tidak sinergis atau berlawanan. Hubungan tersebut diimplementasikan dalam suatu proses kerusakan yang disebut dengan korosi. Sebagian orang dalam bidang keteknikan khususnya di bidang kimia material, aterial dan mesin telah mengetahui arti dari korosi. Tapi korosi (corrosion) selalu diartikan sama dengan islitah karat (rust). Kenyataan kedua istilah tersebut mempunyai hubungan yang berda satu sama lain. Korosi adalah kerusakan material khususnya logam secara umum akibat reaksi dengan lingkungan sekitarnya, sedangkan arti karat dikhususkan pada logam ferrous (besi). Hasil dari proses kerusakan berupa berbagai pdokuk korosi misalnya berbagai macam oksida logam, kerusakan permukaan logam, secara morfologi, perubahan sifat mekanis, perubahan sifat kimia dan banyak lagi jenis-jenis korosi. Adapun dalam makalah ini akan menjelaskan beberapa point sebagai berikut: Korosi logam tak sejenis (Galvanic), Jenis Korosi Intergranular, Korosi Celah, Korosi Erosi, Korosi Teflon, Korosi Sumuran (Pitting Corrosion), Korosi Tegangan, Korosi kelelahan, Biokorosi, Diagram evans dan memperkirakan kinetika korosi, pengendalian korosi, Metalic coating, Inorganic coating serta organic coating.

Speciality coated fabrics combine the beneficial properties of a textile and a polymer, the textile component providing tensile strength, tearing strength, and elongation control, and the coating offering protection against the environment to which the fabric is subjected. Coated textiles have established themselves as one of the important products in the textile global market. There are various methods of application of coating. All these coating methods are developed based on the specific end use of the final product, its cost etc. Micro-level modification of the end product is actually governed by choosing proper coating technique. Coating is important method in the production of artificial leather.

Monitoring visual dan proteksi katodik pada pipa penyalur gas bawah laut sering terkendala akibat kedalaman, arus laut, dan batimetri laut yang akan menyulitkan personil penyelam. Analisis data hasil monitoring visual dengan data rekaman menggunakan Remotely Operated Vehicle (ROV) untuk memonitor kondisi Concrete Weight Coating (CWC), three layer Polyethylen Coating (3LPE) dan kondisi kebutuhan arus proteksi dari bracelet anode akan digunakan sebagai basis data untuk perbaikan bagian yang rusak untuk menjaga intergritas pipa penyalur  dari pengaruh lingkungan dan korosi, studi kasus dilakukan dengan data hasil monitoring pada pipa penyalur gas bawah laut dengan material baja karbon API 5L x65, diameter 28inchi dan panjang 90 km

The effects of chemical dips and edible coatings on firmness and colour of fresh-cut banana (cv. Cavendish) from Madeira Island were investigated. Two calcium salts, calcium chloride and calcium lactate, were first investigated for the effects on firmness during four days of storage at 5°C. Firmness and colour were evaluated after a three-minute chemical dipping or chemical dipping followed by coating and during five days of storage at 5°C. The coatings tested consisted of pectin, alginate, carboxymethylcelullose, carrageenan or chitosan solution. Dip with 1% (w/v) calcium chloride, 0.50% (w/v) ascorbic acid and 0.75% (w/v) cysteine was the most efficient treatment in retarding softening and browning of banana slices. This dip also inhibited yeast growth. According to sensory analysis, the edible shelf life of banana slices dipped in such solution was the longest: five days at 5°C. Carrageenan solution was the significantly (p < 0.05) best coating among the ones studied, in preserving firmness and colour of fresh-cut banana during five days at 5°C.

. Utilization of vegetable oils in coatings. Industr. Crops Products 1: 89-99. Vegetable oils are common raw materials in the coating industry, especially for alkyd resins. These are in common use, but in many industrial coating systems they became second choice because of substitutes based on petrochemical raw materials and which provide an improved technological performance. In architectural coating systems alkyd resins still play an important role because of their benefits such as the economical balance, an uncomplicated application and an outstanding appearance of the films. Water-borne and high solids systems as well as alkyd/acrylic-hybrids will increase their market share for ecological reasons. Apart from alkyd resins, oils are used as reactive diluents e.g. in printing inks, and fatty acids are used as educts for a series of specialty products in the coating industry, e.g., electric insulation systems.

The Application of UV curing technique for poly (vinyl chloride) (PVC) floor tiles coating has improved the quality of PVC floor. Several formulations were made including acrylated oligomers based on a polyurethane were blended with reactive monomers, photoinitiators and other additives. The used oligomers are commercial aliphatic urethane acrylates. Thin films were prepared on PVC tiles by bar coating with different formulations using UV radiation. The coating resins were characterized by FTIR. The properties of UV-cured films such as gloss and adhesion were examined. The properties of UV-cured films dependent on the influence of composition and processing conditions was studied.

Shellac is an animal resin, which has been widely used as a decorative lacquer for wooden handicrafts in the last centuries. It still finds application as wood sealer and finisher because of its peculiar properties. However, there are also some limitations, such as sensitivity to alcoholic solvents and to pH variations and considerable tendency to chromatic variations upon ageing. The aim of this work is to improve some features of shellac by inducing a cross-linking in its structure. Two new materials were obtained by addition of a polyamine and a polyaziridine to shellac, and their performance were studied by different experiments. The varnish obtained by addition of polyaziridine shows a considerably improved performance when compared to plain shellac. In particular, it preserves almost unaltered the chromatic properties of shellac varnish and it shows an increased resistance to alcohols, to basic agents and to artificial ageing caused by a long lasting UV irradiation.

This paper contributes to a review of the research of the fatigue behaviour of
thermal spray coatings on carbon steel. Previous studies provide the experimental
characterization of the fatigue resistance of coated carbon steel. Different coating
powders were deposited to a different type of carbon steels. Also, S-N curves were
drawn from axial- and rotating bending fatigue test to determine the fatigue strength or
fatigue limit of the samples. Thermal spray coatings showed great improvement to the
work hardening effect but worsen the fatigue life due to the inclusion of oxide and pores,
the presence of stress concentrators, and high microcrack density. Moreover, the effects
of the surrounding environment have also resulted in pros and cons towards the fatigue
strength. An improvement, however, can be done with the shot peening treatment, which
significantly increases the compressive residual stress at interfaces of
coating/substrate. The high compressive residual stress could delay the crack
nucleation, thus increasing the fatigue life of the coated part.

The temperature generated by friction and plastic deformation in the secondary shear zone strongly controls tool wear. At lower cutting speeds tool wear is not severe insofar as the temperature is not significant. When the cutting speed is increased, there is a transition in wear mechanisms from abrasion and/or adhesion to diffusion. In the present paper, the change in wear mechanisms as a function of cutting speed and coating material is discussed. The cutting tests were performed on a rigid instrumented drilling bench without the use of cutting fluids. AA2024 aluminium alloy was used to investigate the wear mechanisms of cemented tungsten carbide and HSS tools. Three cutting speeds (25, 65 and 165 m/min) and a constant feed rate of 0.04 mm/rev were selected for the experiments. The best results in terms of maximum and minimum hole diameter deviations and surface roughness are obtained for the uncoated and coated tungsten carbide drills. The results also show that HSS tool is not suitable for dry machining of AA2024 aluminium alloy. q

Aluminium alloy (AA) 6061 and 7075 were reinforced with 10 wt.% of boron carbide (B4C) and 5 wt.% of
graphite through liquid casting technique. The Scanning Electron Microscope (SEM) and Energy Dispersive
Spectrum (EDS) were used for the characterization of composites. The wear experiment was carried
out by using a pin-on-disc apparatus with various input parameters like applied load (10, 20, and 30 N),
sliding speed (0.6, 0.8, and 1.0 m/s) and sliding distance (1000, 1500, and 2000 m). Response Surface
Methodology (RSM) using MINITAB 14 software was used to analyse the wear rate of hybrid composites
and aluminium alloys. The worn surfaces of hybrid composites and base alloys were studied through SEM
and EDS systems and some useful conclusions were made.

Metal coatings are widely used methods for protection
of metal alloys, with the hot dip galvanizing
process being one of the most industrially evolved.
The objective of this work is to carry out a literature
review about the influence of the addition of alloying
elements in the bathroom, on the microstructure
and corrosion behavior of zinc coatings obtained by
the hot dipping technique. It was determined that
the chemical composition of the galvanized baths
influences the microstructural characteristics of the
coatings and their corrosion behavior. The improvement
of the corrosion resistance of zinc coatings is
produced by the addition to the baths of elements
generally more active than zinc, such as magnesium or
aluminum that allow the formation of passive layers
that delay the corrosive process.

Nanocomposite Cr-B-N coatings were deposited from CrB 0.2 compound targets by reactive arc evaporation using an Ar/N 2 discharge at 500°C and −20 V substrate bias. Elastic recoil detection (ERDA), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and selected-area electron diffraction (SAED) were used to study the effect of the N 2 partial pressure on composition and microstructure of the coatings. Cross-sectional scanning electron microscopy (SEM) showed that the coating morphology changes from a glassy to a columnar structure with increasing N 2 partial pressure, which coincides with the transition from an amorphous to a crystalline growth mode. The saturation of N content in the coating confirms the formation of a thermodynamically stable CrN-BN dual-phase structure at higher N 2 fractions, exhibiting a maximum in hardness of approximately 29 GPa.

The result showed that the hardness test using Vickers method of the raw material gave an average hardness value of 327 VHN. Based on the tensile test to the raw material, the average tensile strength was measured for about 1146 MPa. The rotary bending fatigue test result was presented in the S-N diagram (Wohler diagram). It showed that the pressure of 1,4 millibars and coating duration of 5 hours were the optimum parameters for DLC coating. This produced a hardness rate of 625 VHN and a maximum fatigue stress (overload stress) of 744 MPa with a load of 38 kg/mm2. In addition, the fatigue cycle was 12400 cycles. The minimum strain (safe) for steel HQ 805-DLC coating was 516 MPa with the load of 28 kg/mm2 and a fatigue cycle that over 107 cycles. This was beyond the initial minimum strain of raw material that had a value of 400 MPa for the load of 20 kg/mm2. The lowest corrosion rate was 0,0177 mm/year and the lowest Ra roughness of 0,16 μm was reached at coating pressure of 1,4 millibars for 5 hours. It can be summarized that the use of the steel HQ 805-DLC coating on machining application and engine parts designing would be beneficial if operating at the safe condition with an applied load of 28 kg/mm2 and a strain of 516 MPa.

Steel-reinforced concrete is widely used in construction. The corrosion of the steel reinforcing bars (rebars) in concrete limits the service life of concrete structures. Corrosion is one of the main causes for the deterioration of the civil construction and infrastructure. Efficiency of using reinforcing bars coating materials to reduce the effect of water and salt solutions on the steel reinforcement in concrete to extend the life of reinforced concrete structures was investigated in this experimental program. In this study, the concrete used had a compressive strength of 25.5 MPa. Steel rebars were first coated with locally available painting materials in Egypt to investigate the feasibility of protect against environmental effect as chloride attack then, the rebars as well as embedded rebars in concrete were immersed in 5% concentration NaCL solution for 3 months to investigate the corrosion effect by using the bond test before and after chloride attack and rust performing.

The surface of a component is very critical to maintain the proper functions when it is directly exposed to a very harsh environment. Various commercial treatments are available to enhance the surface properties including heat treatment and painting. For over a half of a century, plasmas have been studied for enhancing the surface properties of materials, and in some areas plasma surface engineering is applied to industrial components. In this paper, we will discuss the latest research in this area and various technologies with the emphasis on materials corrosion protection. SwRI has established 12 vacuum systems with the largest size of 8ft long by 4 ft in diameter. The techniques we have developed include plasma immersion ion implantation (PIII), high intensity plasma ion nitriding (HIPIN), ion beam assisted deposition (IBAD), plasma immersion ion deposition (PIID), and plasma enhanced magnetron sputtering (PEMS) deposition. Using these techniques, we have studied various materials including metals and alloys, ceramics and polymers. In this paper, we will present the latest research 2 results in the development of amorphous/nanocrystalline Al-Ce-Co coatings for Al alloys and steels, diamond-like carbon (DLC) deposition on various materials including 1018 steel for erosion and corrosion resistance, and nanocomposite Ti-Si-C-N coatings for applications in extremely erosive and corrosive environments. An overview of the deposition process and several examples of its successful application in manufacturing corrosion resistant coatings are presented. When compared to uncoated surfaces, significant improvement in corrosion resistance was observed.

In this research, the effect of radiation-processed oligo-chitosan on post-harvest loss of litchi fruit was investigated. Different concentrations of irradiated (40 kGy) chitosan solution (500, 1000 and 1500 ppm) were sprayed on litchi fruits both in stalked and stalkless form. Then the treated and untreated litchis were stored in different atmospheric conditions such as at (a) room environment (open and polythene covered) and (b) at 4°C in zip-bag. Fruits coated with irradiated chitosan showed significant delays in the change of weight loss, aesthetic view and microbial count as compared with the uncoated control fruits. The best result was achieved for storage in room temperature at 1500 ppm irradiated chitosan sprayed litchis, where up to 7 days litchis were in good quality. Further improvement was achieved by keeping the litchis in zip lock bag at 4°C. In this case, litchis maintained edible quality with proper aesthetic view up to 21 days. Peeled litchis were also stored at 4°C...

The slurry aluminide coatings were deposited on the three kind of substrates: high– temperature creep resistant cast steel, titanium alloy and nickel alloy. The applied slurry was an active mixture containing aluminium and silicon powders, an activator and an inorganic binder. The coatings were obtained by annealing in air atmosphere. The structure of these coatings was dual-zone and depended on type of the substrate and technological parameters of producing.

In the recent years, silane materials, because of their environmental friendly nature and ease of application have been attended as an alternative for chromate conversion coatings. Different materials were searched for improvement of the efficiency of silane formulation. In this research, pretreatment of carbon steel substrates was carried out using γ-glycidoxypropyl-trimethoxysilane (γ-GPS) as functionalized silane. Cerium nitrate as a corrosion inhibitor material was introduced into the silane material and epoxy resin was applied on the pretreated steel substrates. Effects of the pretreatment on electrochemical properties, cathodic disbondment, dry and wet adhesion strength, and surface morphology of resultant epoxy coating were investigated. Results showed that pretreatment of steel substrate with γglycidoxypropyl-trimethoxysilane (γ-GPS) doped with cerium nitrate leads to improvement of cathodic disbondment and also dry and wet adhesion of epoxy coating. Furthermore, this type of pretreatment reduced the disruption of interfacial bonds at the binder/substrate interface. Addition of 2 wt% cerium nitrate into the silane formulation led to the maximum efficiency of resultant coating.

The scratch resistance and wear behavior at relatively high normal loads of binary (TiN, CrN) and ternary (Al 0.50 Ti 0.50 N, Al 0.68 Cr 0.32 N) coatings were comparatively investigated. Scratch test results showed that based on the adhesive strength the coatings can be ranked thus: CrN > TiN > Al 0.68 Cr 0.32 N > Al 0.50 Ti 0.50 N. The binary coatings were found to possess superior adhesion strength mainly exhibiting a tensile cracking failure mechanism. In contrast, the ternary coatings failed more severely by through-thickness cracking with spallation. The ternary coatings exhibited an average of 68, 67 and 55% improvement in the wear resistance at 15, 20 and 25 N normal loads, respectively, over the binary coatings. Abrasive and oxidation wear were the main wear mechanisms of the binary coatings. The formation of protective tribo-oxide layers is associated with the improved wear resistance behavior of the ternary coatings. High surface roughness due to large amount of surface defects coupled with low plastic deformation resistance and high Al content are reasons for low wear resistance of Al 0.68 Cr 0.32 N in comparison with Al 0.50 Ti 0.50 N coating.

ABSTRACT A multi-scale Finite Element Microstructure MEshfree (FEMME) fracture model for quasi-brittle materials with complex microstructures is applied to simulate thermo-mechanical damage in a plasma-sprayed thermal barrier coating system. This novel multi-scale technique for damage simulation allows the influence of the microstruc-ture of the yttria-stabilized zirconia top coat and the geometry of the bond coat and the thermally grown oxide layer to be considered with computational efficiency. Mechanical damage, due to the thermal strain of an applied temperature difference, is predicted to decrease the top coat Young&amp;#39;s modulus. The interaction between the evolution of damage and temperatures within the top coat is also simulated, demonstrating the capability of this methodology to address coupled multi-scale problems.

— Silica coatings from polysilazane precursors were prepared to protect aluminium substrates from corrosion. Polysilazane can be converted to silica by simple exposition to air or basic vapours and the properties of the synthesized film make this precursor a valuable choice to obtain solid, crack-free, highly adhesive and protective coatings. The optimal deposition, obtained at 15 cm min-1 of dip-coating withdrawal speed, 20% PHPS precursor in n-butyl ether, 24 hours of exposition to 10% ammonia vapours and 6 days of ageing in air, manages to slow down the corrosion process by three orders of magnitude, therefore providing a longer lasting commodity. Specimens have been characterized by IR and XPS spectroscopy, AFM imaging and electrochemical studies.

Polyurethane (PU) is the most common, versatile and researched material in the world. It is widely used in many applications such as medical, automotive and industrial fields. It can be found in products such as furniture, coatings, adhesives, construction materials, Paints, elastomers, insulators, elastic fibres, foams, integral skins, etc. because it has extraordinary properties and the facility to tailormade various formulations according to property requirement using different raw materials which are available. Though the material is having fascinating properties the material is also associated with various problems such as inferior coating properties. Inorganic pigments and fillers are dispersed in organic components and binders to improve different properties of the coating. This paper is intended to review the various nanofillers used in different PU coating systems. It gives a general introduction about the various fillers and it's classification, Mechanism by which the filler enhances the mechanical properties of the materials, various factors which affect the properties of the coatings. Various methods of incorporation of fillers in the coating systems are discussed. Various nanofillers such as SiO2(Silicon Dioxide), TiO2(Titanium Dioxide), AL2O3(Aluminium Oxide), antimony doped tin oxide (ATO), BaSO4(Barium Sulphate), FE2O3(Ferric Oxide) as well as carbon nanotubes, graphene derived fillers and nano-diamonds are discussed in detail. The importance and effect of surface modification of fillers to enhance coating properties are also discussed along with challenges associated with polyurethane coatings and future trends.

This paper describes the influence of silicon carbide (SiC) coating on hydrogen sorption kinetics of zirconium alloy E110 (Zr-1Nb). Amorphous SiC coating of 1.5-µm thickness was deposited on Zr-1Nb alloy substrate by direct current magnetron sputtering of composite cathode. Hydrogen absorption by SiC-coated Zr-1Nb alloy significantly decreased due to low hydrogen permeability of the coating. Hydrogenation tests show that SiC coating provides protective properties against hydrogen permeation in the investigated temperature range of 350-450 • C. It was shown that hydrogenation of uncoated Zr-1Nb leads to formation of δ hydrides at 350 • C and δ and γ hydrides at higher temperatures whereas in the SiC-coated Zr-1Nb alloy only δ hydrides formed. Gradient hydrogen distribution through the SiC coating and H trapping in the carbon-rich interface was observed. The adhesion strength of the coating was ~5 N. Hydrogenation up to 450 • C for 5 h does not degrade the adhesion properties during scratch testing.

Abstract : We optimize the properties and fabrication process of fiber Bragg gratings for sensors and for stabilization of semiconductor lasers. We investigate the effects of boron and titanium doping on thermal sensitivity. We find that gratings written through the polymer coating are stable to high-intensity infrared light traveling in the core of the fiber. These gratings are designed for wavelength locking of semiconductor lasers used for pumping erbium-doped fiber amplifiers. We find that hydrogen-loaded fibers have reduced mechanical strength compared to fiber gratings written without hydrogen. We also investigate the effect of thermal annealing on the strength of fiber gratings. We find that annealing at 230 degrees C slightly improves the fiber&#39;s mechanical strength, while annealing hydrogen-loaded fibers decreases the fiber&#39;s mechanical strength. Bending sensitivity of gratings is measured.

Silicon powders possess good thermal stability and rub resistance and can be used as the filler of high temperature wear-resistant coating; it can possess good wettability and dispersibility in the organic polymer by surface modification of silane coupling agent. Organic silicon has good thermal stability, which can modify the frangibility and thermal stability of epoxy resin. A certain proportion of modified silica powder, curing agent and additives were dispersed to modified epoxy resin can compound wear-resistant coating. The results show that: the modification effect can be the best if the dosage of silane coupling agent is 1.5% of silicon powder. If the methyl triethoxy silane is 50 phr and modified silica powder is 200 phr, then various performances of coating tend to be the best.

In the last decades, mechanical engineering applications have extensive use in many subdomains. Many researchers have used Al2O3 40TiO2 (AMDRY6250) type coatings that have a wide use of plasma jets, significantly improving their wear, corrosion resistance and heat shock properties. It is especially used for hydraulic components such as pumps, impellers, and blowers. The performance of Al2O3 40TiO2 layer is conditioned by a number of technological parameters of deposition, powder granulation and deposition incidence angle. In the present study, the authors will make sequential depositions of Al2O3 40TiO2 on the surface of a material coming from a hydraulic system. Microstructural analysis of optical microscopy, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDAX) are performed both in the surface of the deposited material and in the section of the coated specimens, identifying the microstructure and the component phases. The authors highlighted the emergence ...

This study proposes a new pretreatment method that uses alkoxide precursors with a plasticizing agent; the purpose of this study is to improve the electrochemical and mechanical properties of a galvanized steel surface. Galvanized steel was covered with a hybrid film obtained from a sol that consisted of two alkoxide precursors, 3-(trimethoxysilylpropyl) methacrylate (TMSM) and tetraethoxysilane (TEOS), with nitrate cerium in a concentration of 0.01 M and a polyethylene glycol (PEG) plasticizer. The hybrid coatings were obtained by dip-coating method with various concentrations of plasticizer (0, 20, 40 and 60 g.L-1). The hybrid films were analyzed by scanning electron microscopy (SEM), profilometry, contact angle measurements, a tribometer with the type-setting ball on the plate and electrochemical tests. The addition of the plasticizer into the hybrid films improves the corrosion resistance behavior compared to the sample without the plasticizer. The addition of 20 g.L-1 of plasticizer showed the best performance in the electrochemical tests. The mechanical behavior results indicated that higher PEG concentrations resulted in films with enhanced durability.

Edible coatings and films represent an alternative packaging system characterized by being more environment- and customer-friendly than conventional systems of food protection. Research on edible coatings requires multidisciplinary efforts by food engineers, biopolymer specialists and biotechnologists. Entrapment of probiotic cells in edible films or coatings is a favorable approach that may overcome the limitations linked with the use of bioactive compounds in or on food products. The recognition of several health advantages associated with probiotics ingestion is worldwide accepted and well documented. Nevertheless, due to the low stability of probiotics in the food processing steps, in the food matrices and in the gastrointestinal tract, this kind of encapsulation is of high relevance. The development of new and functional edible packaging may lead to new functional foods. This review will focus on edible coatings and films containing probiotic cells (obtaining techniques, materi...