Corrosion resistance of MA5 magnesium alloy with electric-arc coatings

We study the possibilities of increasing the corrosion resistance of MA5 magnesium alloy by applying aluminum electric-arc coatings from D16 and AMg6 solid wires, a mixture of wires of different kinds (D16 + AMg6), and a powder wire in an aluminum sheath with B₄ C + Ni Cr B Si mixture. The electrochemical characteristics of these coatings are studied in a 3% NaCl aqueous solution. It is shown that aluminum electric-arc coatings strongly increase the corrosion resistance of the alloy. The best characteristics are exhibited by the AMg6 coatings.     

Effect of the laser fusion of electrometallized coatings of the Fe-Cr-B-Al system on their corrosion resistance

We studied the effect of laser treatment of electric arc coatings produced of powder wires of the Fe-Cr-B system on the changes in their structure, electrolytic potential, and polarization currents. We additionally introduced aluminum, nickel, and copper to the charge of these coatings. Laser treatment was realized by means of Nd: YAG laser radiation. We have shown that the addition of a small amount of these elements to the coating under study in different ways affects the character of formation, structure, and electrochemical characteristics of the fused layer. In particular, copper and nickel additions increase the fluidity of the coating. The parameters of laser treatment affect strongly the uniformity of the distribution of elements in the fused zone. In the case of alloying with copper, the nonuniformity of their distribution is more pronounced, which can exert a slight negative influence on the corrosion characteristics of the coating. Aluminum addition improves the corrosion resistance of laser-modified coatings. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 42, No. 6, pp. 106–110, November–December, 2006.     

Effect of the magnetizing current on the structure of coatings obtained by the vacuum electric-arc method

The article examines the effect of the current intensity in a magnetic coil surrounding the cathode on the content of drop phase in coatings and its distribution according to size.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 6, pp. 1009–1014, June, 1988.     

电解液对微弧氧化陶瓷膜结构与耐蚀性的影响

在3种不同的电解液体系中,利用微弧氧化技术在AZ91D镁合金表面原位生长了陶瓷膜．通过扫描电镜、X射线衍射、电化学分析等方法研究了陶瓷膜的形貌特征、相结构及耐府蚀性能．研究表明,在相同反应条件下,不同电解液体系中生成的陶瓷膜结构和性能不同,硅酸钠体系中生成的陶瓷膜厚度大、偏铝酸钠体系中生成的陶瓷膜较薄,偏铝酸钠与硅酸钠的混合体系中生成的陶瓷膜致密、耐腐蚀性能较好．三体系中生成的陶瓷膜中都含有MgO,偏铝酸钠体系陶瓷膜中含有MgAl2O4、硅酸钠体系中含有Mg2SiO4,混合体系中则这两种物质都存在．     

Strength characteristics of coatings in electric-arc metallization

The adhesive and cohesive strengths of powder-wire metal coatings as functions of the technological parameters in electric-arc metallization are investigated experimentally.     

Novel long laminar plasma sprayed hybrid structure thermal barrier coatings for high-temperature anti-sintering and volcanic ash corrosion resistance

1.IntroductionThe artificial-designed segmentation cracks in the ceramic layer of the thermal barrier coatings is an excellent choice by using the atmospheric plasma spray (APS) method under a low cost on the applications of aircraft engines or gas turbine engines.The residual thermal stress energy of the coatings with a certain inter-space of vertical cracks during the thermal cycling test is released through the cracks.The coating with vertical cracks was found out to be superior to other coatings with conventional lamellar structure[1].This process by using the atmospheric plasma spray method usually deposited a dense layer of YSZ (usual thickness of 0.5-1.5 mm) and heating the substrate over 773 K with an auxiliary device previously,even for a complex curved surface of the vanes.     

非晶陶瓷涂层对耐高温液锌涂层耐腐蚀性能的影响

热镀锌技术是钢铁材料表层最为有效的防腐蚀手段。为进一步提高耐锌蚀涂层的使用寿命,采用等离子喷涂技术在熔锌装备表面制备了多级耐锌蚀复合涂层及非晶陶瓷涂层,并利用XRD和SEM对其物相组成、结构及形貌进行了研究。结果表明,非晶陶瓷涂层与熔融锌液存在着不浸润,但耐锌蚀涂层仍然会被腐蚀,镀锌装备内部由于存在温度差使得熔融锌液会进行上下、左右的流动,对非晶层会产生冲刷作用,长时间的冲刷会使非晶层变薄,直至消失。非晶陶瓷涂层的制备在一定程度上降低了加热管的导热性,但可以通过加大功率来进行弥补,封孔后的耐锌蚀涂层的热震性能提高了6倍,使用寿命是原来的2.2倍,延长寿命效果显著。     

Influence of thermal treatment on the corrosion resistance of electrolytic Zn-Ni coatings

This study was undertaken in order to obtain and characterize the corrosion resistance of Zn-Ni coating. The process was carried out under galvanostatic conditions (j = 50 mA·cm^?2) chosen on the ground of an analysis of the deposition process in the Hull’s cell. The Zn-Ni coatings were deposited on austenitic (OH18N9) steel substrate from the ammonia bath. Thermal treatment of Zn-Ni coating was carried out in argon atmosphere. Structural investigations were conducted by X-ray diffraction method. Surface morphology of the obtained coatings was determined using a scanning electron microscope (JEOL JSM-6480) with EDS attachment. The electrochemical corrosion resistance of the prepared Zn-Ni coatings, austenitic (OH18N9) and (St3S) steels, was defined. The studies of electrochemical corrosion resistance were carried out in 5 % NaCl, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. Examinations of localized corrosion resistance were conducted using scanning vibrating electrode technique (SVET). On the grounds of these investigations it was found that Zn-Ni coating after thermal treatment was more corrosion resistant than the Zn-Ni coating before thermal treatment. The relatively good corrosion resistance of Zn-Ni coatings is not as high as the resistance of (OH18N9) steel substrate, but higher compared to (St3S) steel. Therefore, the Zn-Ni coatings may be regarded as a protective coating for St3S steel.     

Electrochemical characteristics of electric-arc aluminum coatings on AZ31 magnesium alloy

The possibilities of improvement of the corrosion resistance of AZ31 magnesium alloy by spraying AlSi5 electric-arc coatings with their subsequent melting by an Nd : YAG laser of quasicontinuous action are analyzed. The electrochemical characteristics of the surface layers in aqueous media are studied. It is shown that the AlSi5 electric-arc coatings significantly increase the corrosion resistance of the magnesium alloy. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 44, No. 5, pp. 112–114, September–October, 2008.     

Effect of polystyrol coatings on the corrosion fatigue resistance of 09G2S steel in sea water

Translated from Fiziko-khimicheskaya Mekhanika Materialov, No. 5, pp. 114–115, September–October, 1990.     

Effect of the structure of the cermet coatings on high-temperature creep of steel

Translated from Fiziko-Khimicheskaya Meckhanika Materialov, No. 6, pp. 103–105, November–December, 1989.     

Geopolymer matrices with improved hydrothermal corrosion resistance for high-temperature applications

Ceramic matrix composites have to overcome two major barriers for applications in aircraft and stationary turbines/engines. One is the unacceptably high processing cost to obtain sufficient mechanical properties and the other is their poor corrosion resistance under hydrothermal oxidizing conditions typical of engines and turbines. Functional geopolymer composites provide possible solutions to the above two problems since they can be formed by technologically simple processing routes and the hydrothermal corrosion resistance can be improved by tailoring material compositions. In this paper geopolymer matrix materials with superior hydrothermal corrosion resistance were processed from the selected geomimetic compositions. The effects of processing parameters, such as particle size, extent of dissolution, and firing temperature on the compressive strength and microstructures were examined and specimens with a compression strength as high as ∼99 MPa were fabricated. Hydrothermal test experiments on KOH-derived geopolymer specimens showed that all of potassium-bonded geopolymer specimens have minimal mass change or dimensional change during hydrothermal exposure in spite of the phase change.