Archive for the ‘Decorative’ Category
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March 1st, 2010
Black gold electroplating
NEW Black gold electroplating on the market!
There is considerable interest in black colour effects on gold jewellery. To date, this has usually been achieved by electroplating black rhodium or black ruthenium layers on carat gold items or by oxidation of special carat gold alloy compositions (see special gold colours on utilisegold.com ) Whilst black rhodium or ruthenium offer satisfactory black coatings, there has been a desire to have a real black gold. At last, Wieland GmbH, Germany, have produced one, called NEOPAL. This is claimed to be “an innovative new decorative surface treatment which deposits a high quality layer of deep black gold plating”. This is a ‘first’ in gold electroplating solutions. I have a ring plated in Neopal; it is a lovely bluish black colour that is very attractive. Neopal is easy to use, with a layer thickness of <10 microns, and has uniform deposition characteristics with a hardness of 60 – 75 HV. For further information, contact Wieland – www.wieland-international.com
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December 21st, 2009
New Book – Gold Science and Applications
I’m excited to announce that a new book ‘Gold – Science and Applications’ has now been published.
There have been many excellent books written on certain aspects of the science and technology of gold, most notably the book of the Hanau gold conference, held in 1996 (“Gold. Progress in Chemistry, Biochemistry and Technology”, edited by Hubert Schmidbaur and published in 1999) and there are several new books covering specific sectors of gold science e.g. on catalysis, chemistry and nanotechnology (see here). However, for those seeking a broader reference source on gold and covering all technical sectors, the most appropriate book on gold, Gold Usage by Bill Rapson and Theo Groenewald, was published over 30 years ago in 1978. The world of gold has changed considerably since then. A few years ago Chris Corti and I believed it was time for an updated book that reflects the more recent developments.
With the co-operation of some of the leading experts in their field, we have attempted to produce a book that is a worthy successor to ‘Rapson’ and to provide an authoritive source of information. We have attempted to cover all the main scientific areas as well as the main areas of application. In some cases this has required some very detailed scientific chapters; other fields require less specific detail and have focused more on the practical application. In addition, to help readers place this science and technology in the context of a much wider gold market, a chapter on the supply, demand and pricing of gold is included. Taken together, our aim for the book is to appeal to both those working in academia and industry.
If you are interested, your can read more and purchase it here .
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October 12th, 2009
Eureka!
This morning on the way to work I read an interesting letter in the London Times. I’m sure all of you will know the famous anecdote of the Greek philosopher and inventor Archimedes – legend has it on stepping into the bath he noticed the level of the water rise, which led to his sudden understanding that the volume of water displaced must be equal to the volume of the part of his body he had submerged. This meant that the volume of irregular objects could be calculated with precision, a task previously extremely difficult. On realisation of this fact, he is said to have leapt out of the bathtub, shouted ‘Eureka!’ (which translates from Ancient Greek to ‘I have found it’), and in his excitement taken to the streets of Syracuse completely naked.
What people are probably less familiar with is the real reason for his joy. Like any good scientist, Archimedes was excited by the potential applications of his Eureka moment. The King of Syracuse had recently set him a task – basically the King had commissioned a new crown be made for him from solid gold. However, when delivered King Hiero II was suspicious that the goldsmith in question had, in fact, not used pure gold but had instead alloyed the gold with silver, effectively making a ‘cheaper model’. Archimedes had realised that he may be able to tell whether the crown was pure gold or not by how much water it displaced.
Like any legend from millennia past, many people have questioned its authenticity. I like to think it’s true though…
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September 28th, 2009
Flashback – gold electroforming
This month’s Chemistry World, the publication of the Royal Society of Chemistry, has an interesting regular feature ‘Flashback’, that looks at what the chemistry world was talking about decades previously. September’s issue looks at the gold crown worn by the Prince of Wales at his investiture on 1st July 1969. The article explains how the crown was, at the time, the largest gold electroform on record. It was made in the laboratory of Engelhard Industries after the design had been presented to BJS Electroplating Company.
Electroforming remains a widely used process for making both decorative and technical parts in gold, whilst minimising weight and cost associated with solid gold pieces.
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September 3rd, 2009
Bayer Innovator Award
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June 18th, 2009
London’s Science Museum and Gold
Whilst I’d love to be reporting a major new exhibition on the wonders of gold science at the Science Museum, alas this post isn’t able to unveil such a development.
However, it does look like gold is going to be a major feature of the Science Museum in the next few years. How? Well, the museum has just announced plans for a major £100 million refit to mark its centenary. The plans include “a gold-plated roof-top cosmology gallery called SkySpace” to quote this story here.
What isn’t categorcally stated is the use of gold leaf for this project, as opposed to the use of imitation gold-coloured paintwork. Experience tells us that the longevity of gold leaf in architectural applications is outstanding, so I do hope they are going to be using gold leaf. Please let us know if you know anymore on these plans……
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May 4th, 2009
Nanotech 2009
This week I will be blogging from Nanotech 2009. At the event, World Gold Council is excited to be co-exhibiting with a range of organisations* who are commercialising technologies exploiting gold’s unique properties at the nanoscale. If you happen to be attending the event, please stop by our booth and say hello. If not check out the links below.
* The organisations exhibiting on the World Gold Council stand this year include:
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March 20th, 2009
Corpus Clock
Question:What do Al Bustan Palace in Oman, The Corpus Clock at Cambridge University and the ‘golden snitches’ from the Harry Potter films all have in common?
Answer: Gold electroplating was used for decoration on each of them.
The electroplating was carried out by BJS in the UK. This company has a Royal Warrant granted from HM Queen Elizabeth II. As well as this seal of quality, what sets BJS Gold apart from its many competitors is that it has invested in the installation of super size electroplating tanks in its manufacturing facility – each with a 10 cubic metre capacity – large enough to hold a small car. That’s well over a million dollars worth of gold in the form of electroplating solution!
Using these large tanks they are able to electroplate hard gold onto very large stainless steel items and they are seeing a growing market for this service in the yachting, architectural and aircraft markets. Interested industrial designers should contact the company to explore the design opportunities.
The electroplating of gold for mainly decorative purposes has been extensively written about in the journal Gold Bulletin.
The Corpus Clock
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March 16th, 2009
Innovations in Textiles
Using the various shapes and sizes of gold nanoparticles as colourants is an interesting technology.
At the ‘Innovations in Textiles 2009: Smart, nano and technical textiles for medical, industrial and clothing applications’ event taking place this week (Wed 18th / Thurs 19th March 2009, at the Royal College of Physicians in London, Professor Jim Johnston from Victoria University of Wellington will present a proprietary new technology.His fine woollen textile products use nanosize gold in different colours within the wool fibre as colourfast colourants, thereby linking the high value and prestige of gold with high quality merino wool, for high value textiles and fashion apparel.
The technology has now been progressed to a small pilot scale operation with the production of demonstration textiles and there are plans to commercialise the process.
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March 2nd, 2009
New patent on Colloidal Gold Production
Colloidal gold is routinely manufactured by many precious metal companies by a process based on the ancient Purple of Cassius route (see L B Hunt, Gold Bull, 9 (4), 24-31, 1976) but with process improvements to give more consistent processes and products. For example, it is used to produce colloidal gold pink enamels for the decoration of pottery and as biomedical diagnostic agents.
The classic Gold Bulletin papers by Turkevich (Gold Bull, 18 (3) 86-91 and 18 (4), 125-131, 1985) describe the process chemistry and properties of the colloids produced. Properties are dependent on colloid particle size but a problem is that it is difficult to produce colloids to a defined particole size in practice at the commercial scale.
Aimed at use as an in-vitro diagnostic agent with improved sensitivity and reliability, a new European patent application from Tanaka KK, Japan, EP2027956 (A1), was published on 25th February 2009. This is aimed at producing gold colloids with a targeted particle size, a sharp size distribution and a uniform, perfectly spherical shape. This process differs from the traditional ones in that it comprises several steps: a nucleation step and one or more subsequent growth steps, each of which involves additions of gold salt solution and reducing agent to the original nucleation solution. In the nucleation stage, a citrate is used as the reducing agent, whereas an ascorbate is used in the growth stages as the reducing agent. The number of growth steps controls the size of colloidal particle attained. The amount of gold salt and ascorbate added in each of the growth stages is defined in terms of a formula related to the number of gold atoms deposited. This method is claimed to produce spherical gold colloids in the size range of about 17 – 220nm plus with a particle size distribution having a standard deviation of 10% or less.
It would be interesting to see how this multi-step approach might be applied to gold catalyst production where nanosized gold particles of tightly controlled size are critical to catalyst performance.
Chris Corti
Richard Holliday
Trevor Keel
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