62 resultados para rare earths


Relevância:

20.00% 20.00%

Publicador:

Resumo:

This data collection addresses the problem of low ductility in magnesium alloys, preventing their wider use. It examines a series of dilute alloys in order to determine the effect of composition on the extrusion behaviour and texture, and on the room temperature tensile ductility.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A wicked problem is what policymakers call a messy social issue with multiple causes and answers that have little hope of pleasing everyone.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A series of rare earth organic compounds pioneered by our group have been shown to provide a viable alternative to theuse of chromates as corrosion inhibitors for some steel and aluminium applications. For example we have shown thatthe lanthanum 4-hydroxy cinnamate offers excellent corrosion mitigation for mild steel in aqueous environments whilerare earth diphenyl phosphates offer the best protection in the case of aluminium alloys. In both cases the protectionappears to be related to the formation of a nanometre thick interphase occurring on the surface that reduces theelectrochemical processes leading to metal loss or pitting. Very recent work has indicated that we may even be able toaddress the challenging issue of stress corrosion cracking of high strength steels. Furthermore, filiform corrosion can besuppressed when selected rare earth inhibitor compounds are added as pigments to a polymer coating. There is little doubtfrom the work thus far that a synergy exists between the rare earth and organic inhibitor components in these novelcompounds. This paper reviews some of the published research conducted by the senior author and colleagues over the past10 years in this developing field of green corrosion inhibitors

Relevância:

20.00% 20.00%

Publicador:

Resumo:

William Wardell’s St John’s College, Sydney, considered the grandest and architecturally most distinguished university college in New South Wales, is an exceptional example of 19th century Gothic Revival architecture.  The information board outside the college states that St John’s is ‘a rare realisation of Pugin’s ideal Catholic College’ and further that ‘it demonstrates [Pugin]’s profound influence on the work of Wardell’. This is but a small part of the story. The commission for St John’s College was far more complex.  The correspondence between the architects, William Wardell, Edmund Blacket and others, and St John’s Council indicates that right from the beginning there was a general lack of understanding of Wardell’s original design concept for the building. This has continued to the present day, as evidenced by the information on the board outside St John’s College, in which it is incorrectly assumed that Wardell’s proposal included a quadrangle as featured in Pugin’s ‘ideal College’. This paper, based largely on primary sources, investigates such claims about St John’s, considers William Wardell and the Gothic Revival, examines St John’s College within the University of Sydney – its design and its translation and posits a few conclusions leading to new understandings.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A preliminary study showed that the inhibitor lanthanum 4-hydroxy cinnamate ((La4OHcin)3) at a concentration of 400 ppm prevented the hydrogen embrittlement (HE) of SAE 4340 steel tensile specimens when tested under slow strain rate conditions in a 0.01M NaCl. In the presence of the inhibitor, a complex film formed on the surface of specimens during the slow strain rate test (SSRT), and no corrosion pits were detected. Electrochemical polarization studies indicated that the La(4OHcin)3 acted as an anodic inhibitor in the NaCl solution. This article also discusses the mechanism of HE inhibition by La(4OHcin)3.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A substantial up-to-date reference manual has been prepared which documents important issues for the supply chain of rare natural animal fibres. New developments in textiles have been included. Cashmere, mohair and camelid fibres have special properties of softness, smoothness and lustre, when compared with sheep wool. They also have other attributes which affect market prices and consumer perceptions, such as being rare and exotic luxuries, and are associated with expensive, comfortable and exclusive garments. These fibres add to the range of wool processing, and add value to wool textiles. Generally, knowledge about these animal fibres is limited, and research effort small compared with research into wool and other natural and man-made fibres. Compared with wool, rare natural animal fibres are more difficult and costly to process. Knowledge about processing these fibres is kept guarded as industrial knowledge. There are problems with clearly identifying rare natural animal fibres when goods are traded or fibres are blended, and fraud is a major concern for textile manufacturers and industry groups. Prickle discomfort in mohair and alpaca next-to-skin wear is a major concern for consumers and textile manufacturers. Natural colours, whiteness and yellowness of rare natural animal fibres are important fibre attributes for dyers and consumers, and the current products have both positive and negative colour attributes for processors. Past investments by RIRDC have made substantial gains in knowledge about fundamental and applied areas of knowledge on the properties, testing and processing performance of rare natural animal fibres.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Speciation of the inhibitors lanthanum 2-hydroxy cinnamate and lanthanum 3-hydroxy cinnamate in solution has been evaluated and compared to the speciation of lanthanum 4-hydroxy cinnamate. The results have been correlated with corrosion inhibition efficiency for AS1020 steel in an aqueous chloride solution using a combination of analytical tools such as nuclear magnetic resonance (NMR) spectroscopy, electrospray mass spectrometry (ESMS), potentiodynamic polarisation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Rare earth organic compounds can provide an environmentally safe and non-toxic alternative to chromates as corrosion inhibitors for some steel and aluminium applications. For steel lanthanum 4-hydroxy cinnamate offers corrosion protection and reduces the susceptibility to hydrogen embrittlement. Recent work has also indicated that it inhibits the corrosion of steel in environments containing high levels of carbon dioxide. For aluminium alloys, cerium diphenyl phosphate provides excellent corrosion inhibition in chloride environments, and reduces susceptibly to stress corrosion cracking. Furthermore, for both steel and aluminium alloys filiform corrosion can be suppressed when rare earth inhibitor compounds are added as pigments to polymer coatings. The levels of inhibition observed are thought to be due to synergistic effects between the rare earth and organic parts of these novel compounds, and are related to the various species that may be present in the complex chemical conditions that develop in solution close to a metal surface. This paper reviews some of the published research conducted by the group at Deakin University over recent years.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The static recrystallisation behaviour of two magnesium alloys after hot rolling have been examined. The alloys chosen for study were the conventional alloy AZ31, and an alloy containing the rare earth element Gadolinium. The recrystallisation kinetics were lower for the rareearth alloy at low annealing temperatures, but at high annealing temperatures the kinetics were higher for the rare-earth alloy. It is suggested that this change in the comparative recrystallisation kinetics is a result of the improved mobility of the rare-earth solute at higher temperatures. This affects the recrystallisation kinetics through solute partitioning to the grain boundaries. The effect of this segregation on the recrystallisation texture is also discussed.