The Experts below are selected from a list of 11118 Experts worldwide ranked by ideXlab platform

A. Amadeh - One of the best experts on this subject based on the ideXlab platform.

  • Study of tribological and friction behavior of magnesium Phosphate Coating and comparison with traditional zinc Phosphate Coating under dry and lubricated conditions
    Tribology International, 2020
    Co-Authors: Peyman Saffarzade, A. Amadeh, Navid Agahi
    Abstract:

    Abstract In this work, the friction behavior of magnesium Phosphate (MP) and zinc Phosphate (ZP) Coatings in different conditions were evaluated. Initially, the Phosphate Coatings were applied on AISI 4130 steel substrate and the optimum Coating conditions were obtained. The Coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS) and magnetic thickness measurement. The friction behavior of both bare and Phosphate coated steels was investigated by means of pin on disc method in three different conditions: dry, continuous lubrication and pre-lubricated. Sodium stearate soap was used as the lubricant. The results indicated that the friction behavior of Phosphate Coatings is not suitable in dry condition; the average friction coefficient and weight loss is high. In this case, the weight loss of ZP Coating is less than MP Coating. The best friction behavior is achieved for zinc Phosphate Coating in continuous lubrication. The average friction coefficient of ZP and MP Coatings are 0.09 and 0.12, respectively. However, in pre-lubricated condition, the friction behavior of MP Coating is better than ZP Coating such that the friction coefficient of ZP and MP Coatings are 0.22 and 0.19, respectively. This difference can be attributed to lubricant adsorption capability of the Coatings.

  • effect of phosphating time and temperature on microstructure and corrosion behavior of magnesium Phosphate Coating
    Electrochimica Acta, 2013
    Co-Authors: M Fouladi, A. Amadeh
    Abstract:

    Abstract In this study a novel Phosphate Coating, magnesium Phosphate, was developed on steel surface. The formation of the Coating was confirmed by X-ray diffraction method. Morphological evolution of the Coating, as a function of phosphating time and temperature, was examined by scanning electron microscope. Magnetic thickness gauge was used to determine the thickness of the Coating and the bath sludge weight was specified to determine the bath efficiency. Corrosion behavior of the samples was studied using potentiodynamic polarization curves. The results indicated that increasing the phosphating temperature facilitated the precipitation of Coating and increased its thickness. Furthermore the best corrosion behavior was observed at 80 °C. Also increasing the phosphating time, enhanced both thickness and uniformity of the Coating. The best results were observed after 20 min of phosphating.

  • Comparative study between novel magnesium Phosphate and traditional zinc Phosphate Coatings
    Materials Letters, 2013
    Co-Authors: M Fouladi, A. Amadeh
    Abstract:

    Abstract In this study, novel magnesium Phosphate as well as traditional zinc Phosphate Coatings were applied on low carbon steel substrate. The Coatings were characterized by means of X-ray diffraction (XRD) and scanning electron microscope (SEM) methods. In addition, magnetic thickness gauge was used to determine the thickness of the Coatings. The results showed that after 20 min of phosphating, magnesium Phosphate Coating (MP) was about 3 times thicker than zinc Phosphate Coating (ZP). It was also noticed that MP endured salt spray atmosphere for more than 2 times longer than ZP without any sign of red rust.

Rongchang Zeng - One of the best experts on this subject based on the ideXlab platform.

  • corrosion resistance of glucose induced hydrothermal calcium Phosphate Coating on pure magnesium
    Applied Surface Science, 2019
    Co-Authors: Lingyu Li, Rongchang Zeng, Xiaobo Chen, Shuoqi Li, Zhenlin Wang
    Abstract:

    Abstract Glucose-induced composite Coatings containing crystalline calcium Phosphate and Mg(OH)2 interlayer were prepared on pure Mg substrate through hydrothermal deposition from alkaline solution. Surface composition, morphology and corrosion resistance of the Coatings were characterized through XRD, FTIR, SEM, XPS, electrochemical and hydrogen evolution measurements. Results reveal that calcium Phosphate Coatings were composed of dicalcium Phosphate anhydrous, calcium-deficient hydroxyapatite and hydroxyapatite. Corrosion resistance of pure Mg specimens was improved by the formation of such a calcium Phosphate Coating. The findings provide a novel strategy to design calcium Phosphate conversion Coatings with satisfactory corrosion resistance for biodegradable Mg implants.

  • corrosion resistance of a novel sno2 doped dicalcium Phosphate Coating on az31 magnesium alloy
    Bioactive Materials, 2017
    Co-Authors: Lanyue Cui, Rongchang Zeng, Guangbin Wei, Yuhong Zou, Enhou Han
    Abstract:

    Abstract A SnO2-doped dicalcium Phosphate Coating was prepared on AZ31 alloy by means of hydrothermal deposition. The results showed that the Coating possessed a globular morphology with a long lamellar crystalline structure and a thickness of approximately 40 μm. The surface of the Coating became smooth with an increase additive amount of the SnO2 nanoparticles. The corrosion current density and hydrogen evolution rate of the Coating prepared in presence of SnO2 were reduced compared to the Coating without SnO2 and the bare AZ31 substrate, indicating an improvement in the corrosion resistance of the SnO2-doped Coating.

  • characterization of calcium modified zinc Phosphate conversion Coatings and their influences on corrosion resistance of az31 alloy
    Surface & Coatings Technology, 2011
    Co-Authors: Linghong Kong, Rongchang Zeng, Yuanding Huang
    Abstract:

    Abstract Two kinds of Phosphate conversion Coatings, including zinc Phosphate Coating and zinc–calcium Phosphate Coating, were prepared on the surface of AZ31 alloy in Phosphate baths. The morphologies of these Coatings were observed using scanning electron microscopy. Their chemical compositions and structures were characterized using energy-dispersive X-ray spectrum, X-ray photoelectron spectroscopy and X-ray diffraction. The corrosion resistance of the Coatings was evaluated by potentiodynamic polarization technique. The results show that the flowerlike Zn–Ca Phosphate conversion Coatings are mainly composed of hopeite (Zn 3 (PO 4 ) 2 ·4H 2 O). They have a quite different morphology from the dry-riverbed-like Zn Phosphate Coatings that consist of MgO, MgF 2 , Zn or ZnO and hopeite. Both of the zinc and zinc–calcium Phosphate Coatings can remarkably reduce the corrosion current density of the substrates. The Zn–Ca Coating exhibits better corrosion resistance than the Zn Coating. Introduction of calcium into the Phosphate baths leads to the full crystallinity of the Zn–Ca Coating.

Fergal J Obrien - One of the best experts on this subject based on the ideXlab platform.

  • influence of a novel calcium Phosphate Coating on the mechanical properties of highly porous collagen scaffolds for bone repair
    Journal of The Mechanical Behavior of Biomedical Materials, 2009
    Co-Authors: Amir A Almunajjed, Fergal J Obrien
    Abstract:

    Lyophilised collagen scaffolds have shown enormous potential in tissue engineering in a number of areas due to their excellent biological performance. However, they are limited for use in bone tissue engineering due to poor mechanical properties. This paper discusses the development of a calcium-Phosphate Coating for collagen scaffolds in order to improve their mechanical properties for bone tissue engineering. Pure collagen scaffolds produced in a lyophilization process were coated by immersing them in sodium ammonium hydrogen Phosphate (NaNH(4)HPO(4)) followed by calcium chloride (CaCl(2)). The optimal immersing sequence, duration, as well as the optimal solution concentration which facilitated improved mechanical properties of the scaffolds was investigated. The influence of the Coating on composition, structural and material properties was analysed. This investigation successfully developed a novel collagen/calcium-Phosphate composite scaffold. An increase in the mechanical properties of the scaffolds from 0.3 kPa to up to 90 kPa was found relative to a pure collagen scaffold, while the porosity was maintained as high as 92%, indicating the potential of the scaffold for bone tissue engineering or as a bone graft substitute.

Jianshe Lian - One of the best experts on this subject based on the ideXlab platform.

  • Influence of sodium metanitrobenzene sulphonate on structures and surface morphologies of Phosphate Coating on AZ91D
    Transactions of Nonferrous Metals Society of China, 2006
    Co-Authors: Li Yuan Niu, Zhonghao Jiang, Li-ping Sun, Dong Han, Jianshe Lian
    Abstract:

    The gray Phosphate Coating was formed on AZ91D magnesium alloy from the zinc phosphating bath containing sodium metanitrobenzene sulphonate in about 4 min. The structure, surface morphologies and phase compositions of the Phosphate Coatings were observed and analyzed by using SEM, XRD and EDS. It is shown that the Phosphate Coating becomes denser and has less micro holes with increasing the concentration of sodium metanitrobenzene sulphonate in the bath in the range of 2.0 to 6.0 g/L. The addition of sodium metanitrobenzene sulphonate greatly increases the micro cathode sites for the formation of the Phosphate Coating and decreases the porosity of the Coating.

  • electroless ni p deposition plus zinc Phosphate Coating on az91d magnesium alloy
    Surface & Coatings Technology, 2006
    Co-Authors: Jianshe Lian, C D Gu, Zhonghao Jiang, Guangyu Li, Qing Jiang
    Abstract:

    Abstract An electroless Ni–P deposition process has been developed to treat the AZ91D magnesium alloy surfaces against corrosion. Magnesium alloy AZ91D was first phosphatized in a zinc phosphating bath containing molybdate. Then an electroless Ni–P deposition was carried out on the Phosphate Coating from a sulfate solution. The phases in the Phosphate Coatings were analyzed by XRD. Microstructures of Phosphate Coatings and electroless Ni–P depositions were observed by SEM and EDS. It was found that there was metallic zinc in the Phosphate Coating and the addition of Na 2 MoO 4 in the phosphating bath resulted in the increase of zinc in the Coating. A lot of disperse metallic zinc particles acted as the catalyst nuclei for the succeeding Ni–P deposition. Consequently, the Ni–P depositions with dense and fine microstructure were obtained on the Phosphate Coatings gained from the phosphating bath wherein 2.0∼2.5g/L Na 2 MoO 4 was added. The Ni–P plus Phosphate Coatings on the AZ91D magnesium alloy exhibited acceptable corrosion resistance as shown by the results of the Salt Spray Corrosion Test.

  • a study and application of zinc Phosphate Coating on az91d magnesium alloy
    Surface & Coatings Technology, 2006
    Co-Authors: Zhonghao Jiang, C D Gu, Guangyu Li, Jianshe Lian
    Abstract:

    Abstract A technology for obtaining the zinc Phosphate Coating on an AZ91D magnesium alloy was investigated. The main ingredients in the phosphating bath were H 3 PO 4 , ZnO and NaF. This Coating has typical Phosphate microstructure, and the compositions in this Coating analyzed by XRD are Zn 3 (PO 4 ) 2 ·4H 2 O, Zn, AlPO 4 and MgZn 2 (PO 4 ) 2 . Scanning electron microscopy (SEM) has shown that very fine zinc particles surrounded Phosphate crystals and filled in the interstice of the insoluble Phosphate. Salt spray tests have indicated that the zinc Phosphate Coating has better corrosion resistance due to the presence of crystalline zinc in the Coating. The zinc Phosphate Coating was used as the base layer for further paint. Salt spray showed that the paint plus Phosphate Coating had good corrosion resistance. The adhesion of paint on the zinc Phosphate Coating was better than that of paint on chromate conversion Coating due to the microporous structure of the Phosphate Coating.

  • A Zinc and Manganese Phosphate Coating on Automobile Iron Castings
    Isij International, 2006
    Co-Authors: Jianshe Lian, Li Yuan Niu, Zhonghao Jiang
    Abstract:

    A modified Phosphate Coating on automobile iron castings was described in this paper. The phosphating bath was modified by adding sodium molybdate. The microstructure of the Phosphate Coating was remarkable refined as the addition of Na2MoO4 increases to 1.5-2.0 g/L. As a result, the corrosion current of the Coatings measured by electrochemical polarization decreases as Na2MoO4 increases, which indicates the increase of the corrosion-resistance of the Coatings. The modified Phosphate Coating was used to automobile castings as an intermediate protect layer before final painting. It was shown that the Coating containing molybdate can improve the adhesion of painting onto the automobile casting. Salt spray test and atmospheric corrosion test indicated that the anticorrosion performance of the paint plus Phosphate Coatings on automobile castings was also improved significantly.

  • A black Phosphate Coating for C1008 steel
    Surface & Coatings Technology, 2003
    Co-Authors: Li Yuan Niu, Jianshe Lian, Zhonghao Jiang
    Abstract:

    This paper describes an effective metal finishing technology for obtaining black Phosphate Coatings on steel. The black conversion Coating obtained on steel (C1008, AISI) and cast iron (No.35, ASTM) was dense and uniform with a thickness up to 18 μm. The Coating shows better corrosion resistance; lubricating ability and higher efficiency of light-absorption than the traditional Phosphate Coatings. The black Phosphate-forming mechanism was investigated. It is shown that sodium molybdate added to the black Phosphate treatment bath can refine the microstructure. Corrosion tests showed that the corrosion rate was lower than that of traditional phosphating. The black Phosphate Coating, when employed as the pretreatment layer before laser heat-treatment, can remarkably improve the efficiency of light-absorption during laser heat-treatment. This Phosphate technology had been employed successfully on the production line in the automobile industry.

Chaosung Lin - One of the best experts on this subject based on the ideXlab platform.