پديد آورنده :
تقي زاده، داود
عنوان :
توليد مستقيم پودر كاربيد تنگستن نانو ساختاراز اكسيد تنگستن به روش آلياژ سازي مكانيكي و سنتز احتراقي
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
شناسايي و انتخاب ساخت مواد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد
صفحه شمار :
دوازده، 74ص.: مصور، جدول، نمودار
يادداشت :
ص.ع. به فارسي و انگليسي
استاد مشاور :
محمدحسن عباسي
توصيفگر ها :
مواد نانو ساختار
تاريخ نمايه سازي :
10/8/91
استاد داور :
علي شفيعي، فتح ا... كريم زاده
تاريخ ورود اطلاعات :
1396/09/20
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
75 Direct Synthesis Of Tungsten Carbide From Tungsten Oxide via Mechanochemical and SHS Methods Davoud Taghizadeh d taghizadeh @ma iut ac ir Date of Submission May 14 2012 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Professor Ali Saidi a saidi@cc iut ac irAbstractTungsten carbide WC is a widely used substance in manufacturing industries because of its higher wear resistance property The high hardness and melting point with excellent abrasive and corrosion resistanceproperties makes it most suitable substance for cutting tool industries There are a number of processesfor the synthesis of tungsten carbide powders and each process varies in the characteristics of thepowder produced including mechanical milling and combustion synthesis techniques which lead toproduce ultrafine grain tungsten carbide Tungsten carbide powders with submicron grain size arecharacterized by a higher abrasive wear resistance and hardness So interest for making nanograintungsten carbide has been growing rapidly during last decades Metalothermic reduction of tungstenoxide by several materials has been done including aluminium magnesium and zinc In this research zincwas chosen as the reducing agent and In situ carburizing via graphite was used for direct synthesis oftungsten carbide Mechanical alloying and Self propagating high temperature synthesis SHS techniquewere employed to produce nanograin tungsten carbide powder Powder mixtures at the stoichiometryratio were milled for 20 40 60 hours and also pellets were compacted by using of a 10MPa press andwere ignited at 800 C and 900 C While characterising the products the path of SHS was studied usingDifferential Thermal Analysis DTA technique Characterizations of the products were done using X raydiffraction XRD method and Scanning electron microscope SEM SHS results showed that withoutmechanical activation at Tig 800 C only Metalothermic reduction of tungsten oxide by zinc takes placeand the products are pure tungsten and zinc oxide At Tig 900 C some zinc tungstate ZnWO4 isproduced in addition to the main products DTA results showed that the minimum temperature requiredto reduce tungsten oxide is 600 C Studies showed that the zinc is melted at the beginning of reactionand wets the surface of tungsten oxide and starts the reduction reaction The heat of metalothermicreduction activates carbothermic reduction too and the rest of the reduction takes place via carbothermisreduction Analysis of milled samples showed that the reduction starts at 40hr of milling to produce theproducts tungsten carbide and zinc oxide and the product of 60hr of milling is amorphous and needs tobe heat treated Phase analysis of the samples heat treated at 800 C confirmed the presence of WC andZnO In order to eliminate the zinc oxide from the tungsten carbide the heat treated product was leachedusing hydrochloric acid The calculated grain size for tungsten carbide after heat treatment was about 10nm Keywords Tungsten carbide Mechanical Alloying SHS Nanostructured
استاد مشاور :
محمدحسن عباسي
استاد داور :
علي شفيعي، فتح ا... كريم زاده
