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Where slags contain metal inclusions there can be some merit in etching to reveal their microstructures; I am thinking in particular of ferrous smelting slags. I would however, carbon coat and examine the slag first, then re-polish, etch and carbon coat again to look at the metal inclusions. David Dr David Dungworth Materials Scientist English Heritage Fort Cumberland Portsmouth PO4 9LD United Kingdom Tel: 023 9285 6783 Mob: 07982 304315 -----Original Message----- From: Arch-Metals Group [mailto:[log in to unmask]] On Behalf Of Dave Killick Sent: 19 February 2009 22:32 To: [log in to unmask] Subject: Re: Question about slag analysis The polished surface of slag samples should not be etched at all. In reflected light and secondary electron mode on the SEM grain boundaries are usually clearly revealed by differences in reflectivity (optical) and topographic relief produced during polishing by differences in hardness of the phases (secondary electron mode). In backscattered mode differences in average atomic number of the phases produce the contrast that made grain boundaries clearly visible. If you are dealing with lead slags there ought to be a big difference in average atomic number between the glassy lead-rich matrix and the relatively lead-poor crystalline phases (e.g. quartz, spinels, perhaps olivines) Carlos Angiorama wrote: > Dear all, > > I want to analyze slag samples to obtain information about the ores smelted, the technology of smelt, and the required temperatures and atmosphere conditions. However, I am not sure about the best way to prepare and analyze the samples I recovered from the site I am studying. It consists of four spanish colonials reverberatory furnaces and I took some samples of slag to analyze. According to geological reports, some previous analysis and historical references, the furnaces could have smelt silver and lead. > > I have already cut the samples of slag, mounted them in epoxy resin and polish its surfaces, using standard procedures for metallographic studies. However, as I plan to analyze the samples with SEM/EDX, I am not sure if I should attack the surfaces chemically to reveal its structure or not (as it is done with metal samples). I should attack slag samples or I should analyze them polished only? > > I have observed the polished surfaces with a metallographic microscope and in most cases, there is a quite uniform surface with some bright inclusions, some oxides and tubular grey shapes. I haven't observed it with cross-polarized light yet, but I will do it to see if I can identify some other phases. > > Thank you very much for your help. > > Best regards, > > > > Dr. Carlos I. Angiorama > > CONICET-Universidad Nacional de Tucumán > > Argentina > > > _________________________________________________________________________________ Concerned about how climate change may affect older properties? What about saving energy? Visit our new website www.climatechangeandyourhome.org.uk today. This e-mail (and any attachments) is confidential and may contain personal views which are not the views of English Heritage unless specifically stated. If you have received it in error, please delete it from your system and notify the sender immediately. Do not use, copy or disclose the information in any way nor act in reliance on it. Any information sent to English Heritage may become publicly available.