Enhanced Oxidation Resistance of Mo–Si–B–Ti Alloys by Pack Cementation

Chromium Deposition on Cobalt-Based Alloys by Pack-Cementation and Behaviour of the Coated Alloys in High Temperature Oxidation

Two TaC-strengthened cobalt-based alloys, with compositions Co-10Cr-0.25C-4.4Ta and Co-10Cr-0.5C-8.7Ta (wt.%) underwent Cr-deposition by pack-cementation, followed by heat-treatment to allow Cr diffusing deeper in their sub-surface. Thereafter they were tested for 50 hours at 1200°C in a thermobalance. These alloys were successfully enriched in chromium, with a maximal content on surface of abo...

Oxidation Resistance of Nanocrystalline Alloys

Stresses induced in alloys by selective oxidation

Consider a substitutional solution of two metallic elements A and B. When the alloy is exposed to air at an elevated temperature, A oxidizes, but B does not. In the alloy, the two elements diffuse in opposite directions, but usually at different rates; the nonreciprocal diffusion is known as the Kirkendall effect. At the oxide-alloy interface, metallic atoms may either emit from or inject into ...

تأثیر ضخامت پوسته Cr2O3 بر مقاومت الکتریکی فولاد AISI 430 پوشش داده شده مورد استفاده در سلولهای سوختی اکسید جامد

In order to increase the efficiency and working life of mettalic interconnects used in solid oxide fuel cells, protective coatings with high electrical conductivity are used. In this study, AISI 430 ferritic stainless steel was coated in a cobalt-base pack mixture by pack cementation. The effect of oxide thickness on the area specific resistance (ASR) was investigated by applying isothermal ox...

Boriding of In-738 Superalloy via the Pack Cementation Method and the Study of the Kinetic of Boride Layer Formation

In this study, mechanism and kinetic of formation of boride layer on In-738 superalloy were investigated via diffusion pack cementation method. Boriding was carried out at 900 °C for several short times (5, 15, 45 and 60 min). Phase study by means of X Ray defragtion (XRD) indicated that in addition to Ni3B, other phases such as Cr5B3, AlB2, and W2B were formed at the first period of process, a...