Study on Surface Modification Coating on High-Purity Mg

2015 ◽  
Vol 713-715 ◽  
pp. 2880-2888 ◽  
Author(s):  
Yong Jun Zhang ◽  
Cui Ling Zhao ◽  
Sheng Tao ◽  
Shu Gong Jia ◽  
Zheng Chun Liu
Keyword(s):  
Surface Modification ◽  
High Purity ◽  
Treatment Time ◽  
Formation Rate ◽  
Microarc Oxidation ◽  
Film Coating ◽  
Ceramic Coatings ◽  
Anode Surface ◽  
Layer Depth ◽  
Two Stages

Microarc oxidation (MAO) surface modification course on high-purity Mg at constant DC and the resultant ceramic coatings were investigated. MAO was the course in which the pre-existing film/coating was modified or substituted and strengthened repeatedly. SEM disclosed the inhomogeneous formation rate of ceramic coating in different micro-regions at anode surface during MAO. Three-stage behavior of MAO including pre-microarc discharge stage, transitional stage and then further modifying stage was put forward. The latter two stages proceeded under continuous discharge conditions, accompanied by intensive evolution of gas. EDS analyses indicated that the resultants of MAO consisted mainly of Mg, O and Si elements. XRD analyses revealed the dependence of phase composition on treatment time and coating layer depth.

Growth of Ceramic Coatings on LY12 Aluminum Alloys by Micro-Arc Oxidation and Microstructure Properties of Ceramic Coatings

2012 ◽  
Vol 508 ◽  
pp. 246-249 ◽  
Author(s):  
Jing Long Gao ◽  
Zhong Cai Shao ◽  
Tong Zhen Li
Keyword(s):  
Aluminum Alloys ◽  
Treatment Time ◽  
Microarc Oxidation ◽  
Cell Voltage ◽  
Sodium Metasilicate ◽  
Ceramic Coatings ◽  
High Rate ◽  
Micro Arc Oxidation ◽  
Al2o3 Phase ◽  
Two Stages

LY12 aluminum alloy samples were treated by microarc oxidation in sodium metasilicate electrolytes. The effects of treatment time on cell violate and ceramic coating thickness were investigated. The results indicate that the micro-arc oxidization process was divided into two stages, at the first stage, the cell voltage increased linearly at a very high rate of 70 V/min, at the second stage, in the range of 430-470 V, the cell voltage reached a relative stable value. The thickness of the coating increased linearly at the whole stage with increasing treating time. XRD analyses indicate that the ceramic coatings fabricated on the surface of aluminum alloys by micro-arc oxidization are composed of Al phase Al2O3 phase. SEM show that the maximum porosity of the ceramic coatings with distributing uniformly pore diameter are decreased with the increasing treatment time.

Sol-Gel Synthesis and Characterization of Ultrafine ZrSiO4 Powder

2014 ◽  
Vol 906 ◽  
pp. 66-71
Author(s):  
Zhen Quan Li ◽  
Qiang Zhen ◽  
Ya Li Wang
Keyword(s):  
Wavelength Range ◽  
High Purity ◽  
Raw Materials ◽  
Formation Rate ◽  
Sol Gel ◽  
Molar Ratio ◽  
Sem And Tem ◽  
Homogeneous Product ◽  
Sol Gel Synthesis ◽  
Calcined Temperature

High purity ZrSiO4 powder were synthesized using Si (C2H5O)4 and ZrOCl2·8H2O as raw materials by the sol-gel method, LiCl was added as mineralizer to promote crystallization of zircon. The influences of molar ratio of Zr:Si, calcined time and calcined temperature on the synthesis of ZrSiO4 powder were investigated. XRD, SEM and TEM were used to characterize the powders. It was found that when the molar ratio of Zr:Si was 1:1.2, the calcined temperature was 1600°C and the calcined time was 4h, the high purity ZrSiO4 ultrafine powder was obtained. The ZrSiO4 formation began at 1300°C and when the gel was calcined at 1600°Cfor 4 h, the formation rate of ZrSiO4 was up to 95%. SEM and TEM studies reveal a homogeneous product with particle sizes on the order of 0.1-1μm. The IR emissivity of ultrafine ZrSiO4 is 0.892 at the whole wavelength range, and that is up to 0.951 at the wavelength range of 8-14 μm.

scholarly journals Surface modification and adhesion improvement of polyester films

2013 ◽  
Vol 11 (1) ◽  
pp. 35-45 ◽  
Author(s):  
Aniello Cammarano ◽  
Giovanna Luca ◽  
Eugenio Amendola
Keyword(s):  
Free Energy ◽  
Surface Modification ◽  
Surface Free Energy ◽  
Self Assembly ◽  
Treatment Time ◽  
Solution Treatment ◽  
Film Surface ◽  
Critical Surface ◽  
Hydrolysis Time ◽  
Critical Surface Tension

AbstractFacile surface modification of polyester films was performed via chemical solutions treatment. Surface hydrolysis was carried out by means of sodium hydroxide solutions, leading to the formation of carboxylate groups. Three commercial polyester films of 100 μm in thickness were used in this work: AryLite™, Mylar™, and Teonex™, hydrolysis time being the main modification parameter. FTIR-ATR analysis, topography and contact angle (CA) measurements, surface free energy (SFE) and T-Peel adhesion tests were carried out to characterize the modified films. A quantitative estimate of the carboxylates surface coverage as a function of treatment time was obtained through a supramolecular approach, i.e. the ionic self-assembly of a tetracationic porphyrin chromophore onto the film surface. The surface free energy and critical surface tension of the hydrolyzed polyesters was evaluated by means of Zisman, Saito, Berthelot and Owens-Wendt methods. It was shown that NaOH solution treatment increases roughness, polarity and surface free energy of polymers. As a result, T-Peel strengths for modified Mylar™ and Teonex™ films were respectively 2.2 and 1.8 times higher than that for the unmodified films, whereas AryLite™ adhesion test failed.

Plasma Surface Modification of Silica and its Application in Epoxy Molding Compounds for Large-Scale Integrated Circuits Packaging

2010 ◽  
Vol 158 ◽  
pp. 184-188 ◽  
Author(s):  
Ming Shan Yang ◽  
Lin Kai Li ◽  
Jian Guo Zhang
Keyword(s):  
Surface Modification ◽  
Acrylic Acid ◽  
Integrated Circuits ◽  
Plasma Polymerization ◽  
High Speed ◽  
Large Scale ◽  
Treatment Time ◽  
Rf Plasma ◽  
Formaldehyde Resin ◽  
Molding Compounds

The surface modification of silica for epoxy molding compounds (EMC) was conducted by plasma polymerization using RF plasma (13.56MPa), and the modification factors such as plasma power, gas pressure and treatment time were investigated systematically in this paper. The monomers utilized for the plasma polymer coatings were pyrrole, 1,3-diaminopropane, acrylic acid and urea. The plasma polymerization coating of silica was characterized by FTIR, contact angle. Using the silica treated by plasma as filler, ortho-cresol novolac epoxy as main resin, novolac phenolic-formaldehyde resin as cross-linking agent and 2-methylmizole as curing accelerating agent, the EMCs used for the packaging of large-scale integrated circuits were prepared by high-speed pre-mixture and twin roller mixing technology. The results have shown that the surface of silica can be coated by plasma polymerization of pyrrole, 1,3-diaminopropane, acrylic acid and urea, and the comprehensive properties of EMC were improved.

Effects of additives in electrolyte on characteristics of ceramic coatings formed by microarc oxidation

1999 ◽  
Vol 15 (2) ◽  
pp. 109-111 ◽  
Author(s):  
Y.K. Wang ◽  
L. Sheng ◽  
R.Z. Xiong ◽  
B.S. Li
Keyword(s):  
Microarc Oxidation ◽  
Ceramic Coatings

EFFECT OF BORATES AND SILICATES ON WEARING PROPERTIES OF MAO COATINGS

2016 ◽  
Vol 24 (05) ◽  
pp. 1750061
Author(s):  
Yu ZHANG ◽  
YAN-WEI ZHAO ◽  
NAN XIANG ◽  
REN-GUO SONG
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Treatment Time ◽  
Microarc Oxidation ◽  
Smooth Structure ◽  
Electrolytic Bath ◽  
Optimum Treatment ◽  
The One ◽  
Wear Tests

In the present study, microarc oxidation (MAO) coatings were formed on ZL101A aluminum alloy in an electrolytic bath containing 3[Formula: see text]g/L KOH [Formula: see text] 2[Formula: see text]g/L Na2WO[Formula: see text] 4[Formula: see text]g/L KF. The morphology and wearing behavior were investigated. In both electrolytes, the additives were borates (Na2B4O718[Formula: see text]g/L) and silicates (Na2SiO3 18[Formula: see text]g/L), respectively. It was found that the coating formed in borates-containing electrolyte was of compact and smooth structure than that of the one formed in silicates-containing electrolyte at the optimum treatment time. It was found that all the coatings were composed of á-Al2O3 and ã-Al2O3. The microhardness and wear tests proved that the coating formed in borates-containing electrolyte was having better mechanical properties than those of the coating formed in silicates-containing electrolyte.

scholarly journals Effect of Anodic Current Density on Characteristics and Low Temperature IR Emissivity of Ceramic Coating on Aluminium 6061 Alloy Prepared by Microarc Oxidation

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Mohannad M. S. Al Bosta ◽  
Keng-Jeng Ma ◽  
Hsi-Hsin Chien
Keyword(s):  
Surface Roughness ◽  
Current Density ◽  
Ceramic Coating ◽  
Microarc Oxidation ◽  
Ceramic Coatings ◽  
Anodic Current Density ◽  
Ceramic Surface ◽  
Anodic Current ◽  
Alumina Phase ◽  
Current Densities

High emitter MAO ceramic coatings were fabricated on the Al 6061 alloy, using different bipolar anodic current densities, in an alkali silicate electrolyte. We found that, as the current density increased from 10.94 A/dm2 to 43.75 A/dm2, the layer thickness was increased from 10.9 μm to 18.5 μm, the surface roughness was increased from 0.79 μm to 1.27 μm, the area ratio of volcano-like microstructure was increased from 55.6% to 59.6%, the volcano-like density was decreased from 2620 mm−2 to 1420 mm−2, and the γ-alumina phase was decreased from 66.6 wt.% to 26.2 wt.%, while the α-alumina phase was increased from 3.9 wt.% to 27.6 wt.%. The sillimanite and cristobalite phases were around 20 wt.% and 9 wt.%, respectively, for 10.94 A/dm2 and approximately constant around 40 wt.% and less than 5 wt.%, respectively, for the anodic current densities 14.58, 21.88, and 43.75 A/dm2. The ceramic surface roughness and thickness slightly enhanced the IR emissivity in the semitransparent region (4.0–7.8 μm), while the existing phases contributed together to raise the emissivity in the opaque region (8.6–16.0 μm) to higher but approximately the same emissivities.

scholarly journals Method of applying protective and electrical insulating ceramic coatings by microarc oxidation under overpressure conditions

2019 ◽  
Vol 1 (5) ◽  
pp. 109-111
Author(s):  
M. A. Markov ◽  
B. V. Farmakovsky ◽  
A. V. Krasikov ◽  
A. D. Bykova ◽  
S. N. Perevislov ◽  
...  
Keyword(s):  
Microarc Oxidation ◽  
Ceramic Coatings ◽  
Electrolytic Deposition

The results of the development of the technology of electrolytic deposition of protective and electrical insulating ceramic coatings are presented. The developed technology consists in the combination of microarc oxidation with the imposition of overpressure in a closed autoclave with the introduction of nanoparticles into the probe of the formation of coatings.

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