ISSN:0267-0844    

DOI:10.1179/sur.1987.3.3.175

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

ISSN:0267-0844    

DOI:10.1179/sur.1987.3.3.177

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

ISSN:0267-0844    

DOI:10.1179/sur.1987.3.3.180

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

ISSN:0267-0844    

DOI:10.1179/sur.1987.3.3.192

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

ISSN:0267-0844    

DOI:10.1179/sur.1987.3.3.195

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

ISSN:0267-0844    

DOI:10.1179/sur.1987.3.3.196

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

ISSN:0267-0844    

DOI:10.1179/sur.1987.3.3.197

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractA new dosimetry technique for use in industrial nitrogen ion implantation is described. This relies on colour changes induced in anodized tantalum. Visual inspection of these dosimeters, by comparison with a set of calibrated standards, provides an accuracy of around±20% over the range 1×1017-5×1017nitrogen ions cm−2. Scope exists for more accurate use of the system by means of commercial colour analysis equipment. However, even as it stands, the material has been shown by field trials to be a useful accessory to commercial nitrogen ion implantation, i.e. for verifying applied dose, especially with complex workpiece geometries, and for evaluating implanter performance.

ISSN:0267-0844    

DOI:10.1179/sur.1987.3.3.203

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractThree cutting tool materials, Coromant ceramic grades CC 620 (based on alumina×zirconia), CC 650 (based on alumina and titanium carbonitride), and CC 680 (based on silicon nitride), were used for evaluation of tool life and wear mechanisms when facing pearlitic flake graphite cast iron without cast skin. Tests were performed at three different cutting speeds, 300, 600, and 800 m min−1, at a feed rate of 0.3 mm rev−1. At 600 m min−1feed rates of 0·1 and 0·5 mm rev−1were also used. CC 680 had the highest feed capability and was the only material that could withstand a feed rate of 0·5 mm−1without fracturing. Tool life was determined by flank wear at all cutting conditions tested except when the highest feed rate was used. CC 620 had the longest tool life and CC 680 the shortest. The main wear mechanism for CC 620 was superficial plastic deformation. In addition, chemical reactions with adhering oxidic layers had influence on the wear rate. CC 650 behaved in a similar way to CC 620. However, the Ti(C, N) phase within CC 650 was worn by diffusion/solution into the work material and also by chemical attack from adhering Fe-Mn silicates. CC 680 was worn almost entirely by a solution/ diffusion wear mechanism. Immersion experiments indicated that composition and thickness of the layers adhering to the flank face could be critical to relative performance ranking of these tool materials. Adherent silicate layers decreased the wear rate of CC 680 due to obstruction of solution/diffusion, whereas the wear rate of alumina based tools increased due to direct dissolution of alumina into the layers. In addition, the wear due to superficial plastic deformation increased as a result of the lower flow stresses of reacted surface layers. Usually, crater wear did not occur due to formation of protective silicate and sulphide layers on the rake face.

ISSN:0267-0844    

DOI:10.1179/sur.1987.3.3.211

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractSpecimens of iron and various steels were ion nitrided in different atmospheres at different ionic energy levels. A collision dissociation model of ion nitriding is proposed, based on the results of ion nitriding tests and calculations of the densities of ions and neutral particles in the cathode potential drop region, incorporating analysis of the collision process and cathode sputtering effects. In ion nitriding there are several possible processes of nitrogen atom migration from gas phase to solid phase, but ion nitriding is achieved primarily by penetration of active nitrogen atoms produced by collision dissociation. The energy conditions of N2, NH3, and N2–H2in collision dissociation were analysed and the amount of active nitrogen atoms was calculated semiquantitatively. The calculated values were in agreement with the results of the nitriding tests. The effects of H2on collision dissociation and the heating of the cathode during ion nitriding are also discussed.

ISSN:0267-0844    

DOI:10.1179/sur.1987.3.3.226

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor