This study aims to determine the major elements of Portland cement type I and II (CEMI and CEMII) in a cement factory in north Tunisia and which metal elements are introduced into the production process. We determine also the metal input rate and their distribution at the entrance and exit of the process. The major elements were analyzed and the trace elements (Arsenic, barium, lead, mercur...

Initial stages of the refractory degradation process by molten Al-5Mg alloy were investigated analyzing structures caused an interaction with metal during heat cycles. The aggregate, found to be poly-crystalline, consisting cristobalite (SiO2) and mullite (Al6Si2O13), was deteriorated ahead surrounding matrix. Metal permeated into refractory, forming a thin layer along crucible surface below li...

Metal particles (Au, Pd and Ni) with an average diameter between 7 to 100 ,~ have been prepared on thin metal oxide films (TiO 2, MgO and A1203), epitaxially grown on refractory metal substrates {Mo(100) or Re(0001)}, and imaged using scanning tunneling microscopy (STM). Information regarding the local electronic structure has been obtained using scanning tunneling spectroscopy (STS). Controlle...

Nickel and aluminum powders were mechanically alloyed with 10 or 30 vol.% refractory metal powders (molybdenum or tungsten) for times up to 50 h. Intermetallic synthesis takes place after lo-20 h alloying, with concomitant dispersion of the inert refractory metal phase, resulting in an NiAl matrix containing fine refractory dispersoids. The reactive synthesis step is direct, without intermediat...

Broadband perfect absorber based on one ultrathin layer of the refractory metal chromium without structure patterning is proposed and demonstrated. The ideal permittivity of the metal layer for achieving broadband perfect absorption is derived based on the impedance transformation method. Since the permittivity of the refractory metal chromium matches this ideal permittivity well in the visible...

The focus of the research reported here was on the design of high-temperature alloys which would form protective Si02 and A1203 scales on exposure to high-temperature, oxidizing environments. One way to promote the growth of such scales is to incorporate sufficient amounts of Si or A1 in the alloy substrate; typically, additions of approximately 35 to 45 weight percent (all alloy compositions a...