بررسي مكانيزم تشكل تركيب بين فلزي Ni3Al طي فرآيند سنتز احتراقي

چكيده انگليسي :

Study on the Mechanism of Ni3Al Formation during Combustion Synthesis Process Nima Tajik n tajik@ma iut ac ir July 1 2009 Department of Materials Engineering Isfahan University of Technology 84156 83111 Isfahan Iran Degree M Sc Language Farsi M Panjepour Assist Prof Supervisor E mail panjepour@cc iut ac ir M Shamanian Assoc Prof Supervisor E mail shamanian@cc iut ac ir G R Arianpour Assist Prof Advisor E mail arianpour@cc iut ac ir Abstract Ni3Al intermetallic compound was extensively investigated due to special properties that show in high temperature Combustion synthesis is one of the new methods for producing the intermetallic High rate of reaction high purity of products and low energy consumption are main characteristics of the combustion synthesis process Because of the high rate of combustion synthesis reaction understanding kinetics and mechanism of the reaction for process controlling and producing of product with required properties are very important Therefore in this study the mechanism of Ni3Al formation from powder mixture of nickel and aluminum with stoichiometric ratio Ni Al 3 was investigated in SHS process Path and mechanism of Ni3Al reaction were proposed the effective parameters on the process were investigated by using microscopic and phase analysis studies After the sample ignition by oxyacetylene flame and combustion wave propagation the sample quenched in liquid nitrogen to stop the reaction Evolution of reactant conversion to product was studied as microstructural in sample quenched by scanning electron microscopic SEM equipped to energy dispersive spectroscopy EDS Also layer by layer phase analysis done by X ray diffraction XRD For evaluation of proposed mechanism accuracy supplementary examination of thermal analysis STA was preformed on powder mixture with different condition It was observed that reaction of the formation of Ni3Al compound during combustion synthesis was preformed in two mode solid liquid and solid solid based on dissolution and precipitation mechanism The path of solid liquid reaction includes dissolution of nickel in liquid aluminum and precipitation of Ni3Al from supersaturated Al Ni liquid and also formation of NiAl compound On the other hand in solid solid reaction path of reaction includes the formation of Ni Al solid solution and then formation of Ni3Al from supersaturated solid solution With increasing interface of powder particle with each other combustion synthesis reaction was preformed in solid solid mode whereas after 40 hour milling of powder mixture starting reaction temperature decreased from 620 C in solid liquid mode to 327 C and reaction doing in solid solid mode In both paths of reactions diffusion control processes are more important in synthesis of the formation reaction Ni3Al compound Keywords Ni3Al Combustion synthesis Reaction mechanism Milling pdfMachine A pdf writer that produces quality PDF files with ease Produce quality PDF files in seconds and preserve the integrity of your original documents Compatible across nearly all Windows platforms simply open the document you want to convert click print select the Broadgun pdfMachine printer and that s it Get yours now

تاجيك، نيما

بررسي مكانيزم تشكل تركيب بين فلزي Ni3Al طي فرآيند سنتز احتراقي

مكانيزم واكنش , آسياكاري مكانيكي