Oxidation Rate of Chromium and 80Ni-20Cr Heater Alloys

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...

اثر متغیرهای جوشکاری میکروپلاسما بر ریزساختار، ویژگی های مکانیکی و مقاومت الکتریکی آلیاژ حرارتی 80Ni-20Cr

در این پژوهش، اثر متغیرهای جوشکاری (شدت جریان، جوشکاری پالسی و غیر پالسی) بر ریزساختار، ویژگیهای مکانیکی (کشش و سختی) و مقاومت الکتریکی آلیاژ 80Ni-20Cr بررسی شده است. برای این منظور، مفتول هایی بـه قطـر 2 میلـی متر تهیه و در شرایط گوناگون مورد جوشکاری قرار گرفتند. سپس نمونه هایی جهت بررسی متالوگرافی نوری، SEM، آزمـون کشش، سختی و مقاومت الکتریکی تهیه شدند. نتایج آزمونهای متالوگرافی نوری و SEM...

Oxidation Kinetics of Chromium and Morphological Phenomena

The oxidation kinetics of chromium at 900~ are independent of the oxygen partial pressure. Although this observation gives evidence for a defect mechanism where chromium interstitials account for the chromium transport in the oxide scale, the experimental phenomena do not support one single model. The occurrence of oxide whiskers and oxide ridges are explained by the energy of activation for th...

Oxidation Resistance of Nanocrystalline Alloys

New Techniques for the Synthesis of Metals and Alloys

Two major areas of effort are encompassed: I. New Techniques for the Synthesis of Metals and Alloys The High Rate Physical Vapor Deposition (HRPVD) process is to be used for the following: 1. Preparation and characterization of Ni and Ni-20Cr alloy sheet 2. Synthesis of compounds Y-O., TiC, Si^N, by reactive evaporation and their characterization 3. Dispersion strengthened alloys, Ni-ZOCr-Y-O ,...