ISSN:0267-0844    

DOI:10.1179/sur.1996.12.3.177

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

ISSN:0267-0844    

DOI:10.1179/sur.1996.12.3.179

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

ISSN:0267-0844    

DOI:10.1179/sur.1996.12.3.182

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractThe 10th Congress of the International Federation of Heat Treatment and Surface Engineering, incorporating the 3rd ASM Heat Treatment and Surface Engineering Conference in Europe, covered all aspects of these technologies in an extensive technical programme linked to an impressive poster display, reports XIAOYING LI of the School of Metallurgy and Materials, University of Birmingham.

ISSN:0267-0844    

DOI:10.1179/sur.1996.12.3.209

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractCarbon steel coatings can be employed for hardfacing mechanical components used in moderately aggressive wear environments, provided they are sufficiently hardened by retained carbon. However, when thermal spraying using compressed air as the atomising gas, properties of carbon steel coatings are degraded by carbon loss through oxidation and oxide inclusions. It is shown that the physical and mechanical properties of these coatings can be greatly improved by spraying with inexpensive nitrogen produced on site by pressure swing adsorption or membrane separation, without the cost penalties incurred when using pure nitrogen. In some circumstances, such coatings can be used to replace more expensive alloy hardfacing layers.

ISSN:0267-0844    

DOI:10.1179/sur.1996.12.3.217

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractThe structure and composition of an innovative Ti-Cu intermetallic coating has been investigated by means of metallographic examination, X-ray diffraction, glow discharge optical spectroscopy, and microhardness measurements. For this purpose, Ti-6Al-4V substrates were coated with a uniform layer of copper by an electroplating technique, then a diffusion anneal was conducted in an argon controlled atmosphere. Microstructural examination revealed that the compound coating microstructure consisted of four layers: the outer two layers are composed of various intermetallic compounds, including TiCu3+ Ti3Al and TiCu; the third layer is the transformation product of theβphase electroplatformed at the diffusion temperature, which containsα- Ti and Ti2Cu; and the fourth layer was identified as the product of this transformation precipitated mainly at proeutectoid (α- Ti boundaries. These microstructural features reveal the two essential characteristics of the coatings, namely the continuous layers of intermetallic compound and a substrate hardened by inward diffusion of a substitutional alloying element.

ISSN:0267-0844    

DOI:10.1179/sur.1996.12.3.221

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractThe layer morphology and structure resulting from the glow discharge plasma chromising of steels containing 0·22, 0·45, 1·0, and 1·2%C are discussed. The growth kinetics of chromium and carbide layers has been investigated; the relationship between layer thickness and chromising time follows a parabolic law. An equation for growth of the surface carbide layer as a function of matrix carbon activity and chromising time has been derived. The calculated and measured values are in good agreement. It is shown that ion bombardment accelerates chromising.

ISSN:0267-0844    

DOI:10.1179/sur.1996.12.3.225

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractLayers produced on low carbon steel and Armco iron during vacuum chromising have been investigated. In particular, the influence of two fundamental factors, the surface area of the sublimating metallic chromium and the pressure within the furnace chamber, is discussed. Layer thickness and morphology, and the chromium and iron concentrations in the diffusion zone of chromised layers, have been studied. Layers consisting of solid solutions of chromium in iron resulted in all instances. Chromising conducted at low pressure, with a static rather than a dynamic vacuum, was found to be most effective for maximising the rate of growth of diffusion layers. Scanning electron micrographs of the surfaces of chromised low carbon iron alloys show the presence of microsteps characteristic of screw dislocations. Hence, it is concluded that the growth of diffusion layers during vacuum chromising depends on the generation and growth of dislocations according to Frank‘s spiral lnechanism model.

ISSN:0267-0844    

DOI:10.1179/sur.1996.12.3.229

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractThe effect of laser remelting on the microstructure, porosity, and chemical homogeneity of cobalt based and nickel based alloy coatings plasma sprayed on stainless steel substrates has been investigated. Coating, nicrostructure and density were markedly improved by laser melting and much better chemical homogeneity was obtained. The micro hardness and corrosion resistance of the coatings were also enhanced significantly following laser melting.

ISSN:0267-0844    

DOI:10.1179/sur.1996.12.3.235

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractElectron beam surface melting has been carried out on a complex aluminium bronze, CA104. The structural changes have been studied using optical microscopy, scanning and transmission electron microscopy, and X -ray diffraction analysis. The effect of surface melting on hardness, rolling–sliding wear resistance and friction coefficient, and electrochemical corrosion properties has been investigated. It was found that the surface melting transformed the originalα+ K structure into a martensitic one. Consequently, the hardness was almost doubled in the melted region. Subsequent tempering further increased the hardness. When running against a hardened steel in dry rolling–sliding wear both the weight loss and the coefficient of friction were reduced by surface melting. Electrochemical corrosion tests also showed an improvement in corrosion resistance in simulated cooling water after surface treatment.

ISSN:0267-0844    

DOI:10.1179/sur.1996.12.3.239

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor