DARPA instituted an Initiative in Titanium in 2003 to produce titanium, alternatively to the Kroll process, in a billet form for under $4/lb. This DARPA sponsored program has gone into Phase II consisting of utilizing ore/TiO2 as a feed. The TiO2 is carbothermically reduced to a suboxide-carbide (Ti:O:C) which is used anodically to resupply the titanium content in an electrolysis process that deposits titanium in a powder morphology. The deposited powder is uniquely stripped from the cathodes and harvested in a separate stream that permits continuous electrolytic processing to produce titanium at an estimated cost about (1)/(2) the Kroll process. Oxygen contents less than 500 ppm are achievable with particle sizes in the desired range for powder metallurgy applications. The process has been demonstrated on a continuous basis and is in the stage of scaling-up to 500 lbs/day.

It has long been a goal to produce Ti Alloy powder directly to eliminate the standard processing of melting sponge, alloying, producing a billet/ingot and then reducing to powder by one of several techniques. The batch Kroll process where reaction occurs at the reactor wall interface from TiCl4 vapor and molten magnesium, limits the potential to directly form alloys. Any batch processing has the limitation of alloy compositional control from batch to batch. A unique continuous processing approach permits the gaseous mixing of chloride precursors with metallothermic reduction that directly produces an alloy powder in a size that is useable for standard powder metallurgy. Discussion will include producing Ti-6Al-4V and other alloy powder.

In the standard Kroll process reaction between the TiCl4 and Mg is at the reactor wall interface that limits the potential to design a continuous process. Many alternatives have been investigated over the past 70 years to engineer a continuous process utilizing metallothermic reduction of TiCl4. Approaches utilizing burner type architectures for continuous processing result in unacceptable very fine Ti powder. A unique process that operates continuously and produces controlled size powder that can be directly utilized in standard powder metallurgy, rapid manufacturing, or substituted for sponge will be discussed.

Excavations in 1964 at the Pine Spring site in southwest Wyoming concluded that the site contains three cultural occupation levels; the earliest allegedly dates to the terminal Pleistocene and is associated with megafauna. However, excavations in 1998 and 2000, and analysis of the stratigraphy, AMS dates, micromorphology, and artifact carbonate isotopes, along with debitage refitting, density, orientation, inclination, burning, and trample damage, could not replicate the 1964 findings. A hiatus in deposition accounts for the highest density of artifacts, and the three original occupations are palimpsests. There is no unequivocal association between evidence of human activity and megafaunal remains. © 2006 Wiley Periodicals, Inc.

School Science and MathematicsVolume 41, Issue 2 p. 115-118 THE DETERMINATION OF MOLECULAR DIMENSIONS BY THE OIL FILM METHOD John Laughlin, John Laughlin Haverford College, Haverford, PennsylvaniaSearch for more papers by this author John Laughlin, John Laughlin Haverford College, Haverford, PennsylvaniaSearch for more papers by this author First published: February 1941 https://doi.org/10.1111/j.1949-8594.1941.tb05411.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume41, Issue2February 1941Pages 115-118 RelatedInformation