Among older adults whose diets are high in saturated and trans fats, a high intake of copper may be associated with an accelerated rate of decline in thinking, learning and memory abilities, according to a report in the August issue of Archives of Neurology, one of the JAMA/Archives journals.

Although copper, zinc and iron are essential for brain development and function, an imbalance of these metals may play a role in the development of brain plaques associated with Alzheimer's disease. Previous studies have also linked fat intake, especially that of saturated and trans fats, to Alzheimer's disease and other forms of cognitive difficulties, according to background information in the article. One recent animal study found that the consumption of copper in drinking water could amplify the degenerative effects of a high-fat diet on rabbit brains.

Martha Clare Morris, Sc.D., Rush University Medical Center, Chicago, and colleagues assessed the connection between dietary fat and dietary copper intake in 3,718 Chicago residents age 65 years and older. Participants underwent cognitive testing at the beginning of the study, after three years and after six years. An average of one year after the study began, they filled out a questionnaire about their diets. The dietary recommended allowance of copper for adults is .9 milligrams per day. Organ meats, such as liver, and shellfish are the foods with the highest copper levels, followed by nuts, seeds, legumes, whole grains, potatoes, chocolate and some fruits. Copper pipes may also add trace amounts of the metal to drinking water.

Cognitive abilities declined in all participants as they aged. Overall, copper intake was not associated with the rate of this decline. However, among the 604 individuals (16.2 percent of the study group) who consumed the most saturated and trans fats, cognitive function deteriorated more rapidly with the more copper they had in their diets. "The increase in rate for the high-fat consumers whose total copper intake was in the top 20 percent (greater than or equal to 1.6 milligrams per day) was equivalent to 19 more years of age," the authors write.

Other metals assessed in this study, iron and zinc, did not show any effects on cognitive decline in interaction with a high-fat diet. Previous studies have found higher levels of copper in the blood of patients with Alzheimer's disease, and medications that bind with copper to block its effects have shown promise treating patients with the condition.

Expectant mothers may someday get a personalized menu of foods to eat during pregnancy to complement their genetic makeup as a result of new research at Washington University School of Medicine in St. Louis. Researchers used transparent fish embryos to develop a way to discover how genes and diet interact to cause birth defects.

"By the time most women know they are pregnant, the development of the fetus' organs is essentially complete," said Bryce Mendelsohn, co-author and an M.D./Ph.D. student in the Medical Scientist Training Program at Washington University School of Medicine. "Since we currently do not understand the interaction between genetics and nutrition, the goal of this research was to understand how the lack of a specific nutrient, in this case copper, interacts with an embryo's genetics during early development."

Mendelsohn is doing the research in the laboratory of Jonathan D. Gitlin, M.D., the Helene B. Roberson Professor of Pediatrics at Washington University School of Medicine, director of genetics and genomic medicine at St. Louis Children's Hospital and scientific director of the Children's Discovery Institute.

Mendelsohn and collaborators Stephen L. Johnson, Ph.D., associate professor of genetics at the School of Medicine, and graduate student Chunyue Yin, working with Lila Solnica-Krezel, associate professor of biology at Vanderbilt University, studied the impact of copper metabolism on the development of zebrafish, a vertebrate that develops similarly to humans. Zebrafish have become staples of genetic research because the transparent embryos grow outside of the mother's body, which allows development to be easily observed. The study's results appear in the August issue of Cell Metabolism.

Using techniques designed to get to the core of how the body processes copper, the researchers identified a gene in zebrafish responsible for copper metabolism, called atp7a. They found that variants of the atp7a gene led to the abnormal metabolism of copper, which resulted in impaired development of the fish's notochord, similar to the spine in humans.

In humans, copper is found in all body tissues and is critical for maintaining stable iron levels, connective tissue formation, nerve cell function in the brain, hormone production and pigmentation. The trace metal is commonly found in shellfish, nuts, chocolate and liver.

"Whether a zebrafish embryo has enough copper to develop normally depends not only on the total amount of copper, but on how well this gene functions," Mendelsohn said.

Menkes disease is an inherited disorder of copper metabolism caused by a mutation in the human version of the ATP7A gene. Children who have Menkes disease have seizures, neuronal degeneration, abnormal bone development and kinky, colorless hair. The disease, although very rare, is untreatable and fatal.

The discovery of a vertebrate model to examine copper metabolism in early development will contribute to the understanding of the role of copper in structural birth defects such as scoliosis, an abnormal curvature of the spine. In addition, the availability of the zebrafish model of Menkes disease permits the development of novel therapeutic approaches in affected patients.

The researchers next plan to adapt these same methods to find other genes that affect the body's use of important nutrients during early development. This could provide insight into how poor nutrition and genetic variation act together to contribute to birth defects. "We already know that nutrition is a critical issue in birth defects and that folic acid is an essential supplement in some women for the prevention of spina bifida in the developing fetus," said Gitlin. "The ultimate goal of this research is to bring the power of genomic medicine to every woman. The knowledge of genetic variations serves as a unique, individual guide for providing the essential nutritional intake that will ensure a normal, healthy infant."

The research is also the first scientific discovery to emerge from the Children's Discovery Institute, a collaboration between St. Louis Children's Hospital and Washington University School of Medicine to fund unique research initiatives in child health.

Research and Development

Today’s R&D departments at modern polymers and plastic manufacturers are not only busy designing new products and developing innovative materials; they are often asked to help in solving customer complaints and production problems, and are consulted when internal norms and procedures are being established.
Monitoring of Manufacturing Processes

Another task that modern R&D departments are involved in is the central monitoring of the overall manufacturing process. For such an environment often standardless analysis and analyses of elements with low atomic numbers are important. PANalytical's highly sensitive WDXRF (wavelength dispersive XRF) spectrometer Axios is the ideal system for R&D departments.
The Axios Spectrometer from PANalytical

The Axios spectrometer comes with the powerful and flexible SuperQ 4 analysis software. Several program options are available to extend the functionality for dedicated types of analysis. For instance, the IQ+ option offers standardless quantitative analysis of completely unknown samples.
X-Ray Fluorescence Systems in Production Environments

In this part of the plastic and polymer manufacturing, XRF analysis systems are usually "tuned" to the particular process and will be working in a standard configuration. Automatic sample changing often is an additional request from production to simplify control processes. Especially when high sample throughput is important, these applications require flexibility, sensitivity and speed from a reliable and robust XRF system: the ideal environment for Axios.

In production and process control reliability is a must as well as accuracy and precision. Once properly set up, XRF analysis should not be more than a push-button operation. Ease-of-use also for less experienced users and an excellent service is what industry demands. Combining high-power X-ray excitation, the company’s proprietary fourth-generation counting electronics and other proven features, Axios has become the system of choice for fast and reliable XRF analysis.
Software for X-Ray Fluorescence Systems

Parameters and analysis results within production and process control often need to be compatible with and integratable into a LIMS system. PANalytical offers a range of software modules to make its systems perfectly fit into its environment.

SuperQ, the MagiX software, provides a data transmission as standard and offers UAI (Universal Automation Interface) as additional module.
Statistical Process Control

The SPC (Statistical Process Control) software of PANalytical provides valuable information about plant production trends. Moreover, with regular measurement of designated quality samples it also enables long-term spectrometer performance to be monitored, in accordance with Good Laboratory principles.
Quality Control

Quality management involves people, processes and machines. They all strive to meet the users' needs at the right time and at the right price. One of the analysis tools for quality management is XRF spectrometry, not only because XRF is a non-destructive technique, but also because it enables qualitative and quantitative analysis of fluids and solids.
Benchtop Systems

The PANalytical cost-effective spectrometers such as the Venus and the benchtop systems are valuable tools for stand-alone or satellite units. Especially in those conditions where throughput is low (10-15 samples within a day) and an adequate analysis is demanded.

These spectrometers are perfect stand-alone units for the smaller and/or remote plants, since it often is more convenient to measure the samples at the satellite rather than sending them to the main laboratory, which would usually be equipped with larger and more sensitive systems. Furthermore, these benchtop spectrometers are perfect back-ups when main-line systems are in service/maintenance.
The Venus WDXRF Spectrometer from PANalytical

With Venus PANalytical offers a compact easy to use WDXRF spectrometer for cost effective elemental analysis of elements from F to U. Venus as well as the EDXRF bench top systems MiniPal and MiniMate do not require highly qualified personnel to operate them. Small laboratories with no special infrastructure will enjoy all these systems which stand for precise and quick analysis and ease-of-use. Of course, all of the products of the Mini series work with the state-of-the-art analytical software providing utmost flexibility and control possibilities.
Recycling

One of the growing applications within the industry is recycling – a branch which almost daily increases in importance because of the awareness of environmental issues.

Recycling of plastics is a demanding task. First of all, the collected plastics must be fully identified, this is where XRF takes its important role. It is ideal looking for the additives in plastics and checking for certain chemical elements frequently present such as Sb, Br, Cl, Fe, Cu and Ti used as fire retardants or pigments.
Sorting Of Recycled Plastics

MiniPal is an ideal tool for qualitative sorting of different plastics, PVCs or polyethylenes.

Modest costs make the Mini series a practical choice for sample pre-scanning or as back-ups to other mainline systems. If you’re looking for more difficult traces, smaller quantities, pigments or the additives which identify the same plastic but different manufacturer; the Axios is the solution. Of growing importance is the elemental analysis of heavy metals. The Epsilon 5 is optimized for this application.

TOXEL Standards For Analyzing Heavy Elements In Polyethylene

In 2004, PANalytical cooperated with DSM Resolve to launch TOXEL – the first set of standards for analyzing toxic heavy elements in polyethylene.

TOXEL helps manufactures of plastics and polymers to meet the EU’s RoHS and WEEE directives, which require quantitative elemental analysis down to sub-ppm levels.
TOXEL Certified Standards

TOXEL provides certified standards against which to perform this analysis by incorporating five standards (one blank and four multi-element standards) containing the regulated elements: Cr, Cd, Hg, Pb, As, Ni, Cu, Zn, Ba and Br.

A single set of TOXEL calibration standards can be used to calibrate all regulated toxic elements, covering trace levels up to a few hundreds of ppm.
Primary Applications fro TOXEL Standards

TOXEL is primarily for use with XRF analysis – one of the best methods of measuring sub-ppm levels of toxic elements.

Establishing a calibration with TOXEL standards and PANalytical’s Epsilon 5 or Axios spectrometers is simplified because XRF is a multi-element technique.

When applied in combination with PANalytical’s XRF spectrometers, TOXEL helps plastics manufacturers meet the challenges and opportunities of plastics manufacturing in the 21st century.

Sony Corporation today announced the accomplishment of the world’s first Mercury-free silver oxide battery, which was considered difficult within the industry. Starting January 2005, 10 models of mercury-free batteries will be commercialised on a world-wide basis.

Sony is producing Silver Oxide batteries of all sizes and currently Sony has the top market share. Silver Oxide battery is mainly used for wrist watches, small-size thermometers and mobile game products. Sony started its Silver Oxide battery business in 1977 and, as of September this year (2004), Sony has realized in producing 5 billion cells of Silver Oxide battery cumulatively.

The mercury-freeing technology development announced this time will very much influence the increasing interest of the effect that mercury incorporate in batteries has on environmental issues. Currently, revisions in the battery directives are being made in the European Parliament and European Environmental Council, however it is expected that freeing mercury from silver oxide batteries will be an exception, due to the difficulty in realizing it. However, the new Sony’s 0% mercury silver oxide battery made this possible.

Annually, Sony sells approx. 400 Million Silver Oxide batteries worldwide, and considering the fact that the mercury level of Sony’s silver oxide batteries is 0.2% of the total content of a battery, making them mercury-free will lead to reducing the annual usage of mercury by 320 kg, which dramatically contribute to protecting the environment.

Also, in the European battery directives, the determinations on the regulation of the level of lead is also under discussion (i.e. to be less than 40ppm), and it should be emphasized that in Sony Mercury-free silver oxide batteries usage of lead has also been eliminated.

The function of Mercury in Silver Oxide Battery

Silver Oxide battery is a small-sized primary battery using Zinc as the negative electrode (anode), Silver Oxide as the positive electrode (cathode) plus an alkaline electrolyte (figure 1).

Figure 1. Schematic diagram of silver oxide battery cell.

Zinc which is the activator in the negative electrode will corrode in alkaline solution and it is consumed. When this happens, it becomes difficult to maintain the capacity of the unused battery. This corrosion of Zinc also causes electrolysis in the electrolyte and brings about the production of Hydrogen gas, which will result in ascent of inner pressure and expansion of the cell. (Fig. 2). And for this reason, mercury which suppressed the corrosion of Zinc was added in the battery, however it was desired for mercury to be reduced, for its considerable harm to the environment.

Figure 2. The role of mercury in conventional silver oxide battery cells.

Counter measures to realizing a Mercury-free Silver Oxide Battery

With the below explained three technical countermeasures, Sony has succeeded in preventing the Zinc corrosion (i.e. Hydrogen gas generation), which is indispensable for the achievement of Mercury-free Silver Oxide battery.

Adoption of high quality Zinc alloy powder with improved corrosion resistance
By optimising the mixed ratio of fine metal used (i.e. Zinc-alloy powder), it has been managed to dramatically reduce the corrosion rate, 10 times less, compared to conventional material.

Addition of anti-corrosion material into anode materials
This additive can prevent the generation of Hydrogen gas by blocking the gas-generation spots. This leads to reducing the corrosion rate by a half, thus reducing the Hydrogen gas generation dramatically.

Adoption of anti-corrosion technology to the collector materials
Suppressing the corrosion of the collector electrode has an effect of suppressing the corrosion of Zinc as well, however on the other hand, if not processed properly, it caused leakage of the inner electrolyte. Using Sony's unique technology used in electronic device manufacturing, which is to do with surface process technology, Sony has managed in enhancing the accuracy of processing, succeeding to achieve anti-corrosion and to prevent liquid leakage at the same time.

Additionally, a Sony-unique active cathode material, which Sony has adopted from its current cells, has high hydrogen absorption capacity, resulting in the maintenance of a safe cell. (i.e. problem of cell expansion caused by hydrogen gas is solved). In addition, as a typical evaluation parameter of batteries, it has been achieved to improve the battery conservation capabilities as well.

As for the patents related to the development of mercury-free silver oxide batteries, applications of 5 patents have already been made in Japan, USA and Europe.

Sony will target to eliminate mercury from all Silver Oxide battery cells and will continue to pursue the advancement of environment-conscious technology.

Background

Vacuum plasma processing is already a well-proven and widely-used technique for etching and surface modification in the electronics industry. It is being increasingly used by the aerospace, automotive, medical, military and packaging industries for cleaning and surface engineering of plastics, rubbers and natural fibres as well as for replacing CFCs for cleaning metal components.
Range of Application

Applications range from cleaning tiny components like ball point pen nibs, through surface engineering of reels of web and film materials, to adhesion promotion of whole automotive plastic bodies. There are only two real constraints - can the product fit into the vacuum chamber, and is it vacuum compatible? If the product is too big or if under vacuum it would continuously produce evolvements, such as moisture or gases, then it is not be suitable for plasma treatment.
What is it used for?

Vacuum plasmas can be used to clean surfaces and remove organic residues, or to promote adhesion before painting, lacquering, printing, electroplating or adhesive bonding. Materials can be modified or ‘surface engineered’ to change the surface properties without affecting the bulk material.
Surface Engineering

Surface engineering can improve properties such as frictional behaviour, lubricity, heat resistance, cohesive strength of films, surface electrical conductivity, or dielectric constant, or it can make materials hydrophilic or hydrophobic.
Adhesion

For good adhesion, thorough and consistent surface cleaning is essential, but is often difficult to achieve. After mechanical cleaning or surface preparation, loosely attached particles are often left on the surface. Aqueous cleaning tends to dissolve localised bulk residues but then, on evaporation, redeposit them as a thin film over the whole surface. This film can be extremely difficult to remove except by plasma or other radiation treatments. Vacuum plasma cleaning can remove all residues and leave the surface ‘atomically clean’.
Adhesion Promotion

Adhesion promotion can be achieved using reactive gases. These produce chemical species and free radicals, which react with or deposit onto the surface, improving the affinity to the adherent surface by forming chemical or electrical bonds. Non-reactive, noble gas plasmas with heavy ions cause topographical changes to the surface and thereby improve mechanical bonding. They can also create surface radicals through mechanical damage to the atomic structure. These radicals can then participate in surface reactions and bonding.
The Process

Vacuum plasma treatment is a low temperature process, typically at 40-120°C, which can thus avoid thermal damage. The process can induce non-thermally activated surface reactions, causing surface changes which cannot occur with molecular chemistries at atmospheric pressure. These unique properties can open up new opportunities for materials and products.

Plasma processing is conducted in a controlled environment inside a sealed chamber, which is maintained at a medium vacuum, usually 13-65 N.m-2, by the introduction of selected gases, figure 1. The gas or mixture of gases is energised by an electrical field from DC to microwave frequencies, typically 1-5000 W at 500 V. The components to be treated are usually electrically isolated. The volatile plasma by-products are evacuated from the chamber by the vacuum pump, and if necessary can be neutralised in an exhaust scrubber.

Unlike liquid cleaners and etchants, which use only molecular chemistry, plasmas employ molecular atomic, free radical and metastable species for chemical effects, and electrons and positive ions for kinetic effects. Plasmas also generate electromagnetic radiation, in the form of vacuum UV photons, which can penetrate bulk polymers to a depth of about 10 µm. This can cause chain scissions and cross-linking.

Ionisation tends to occur at higher energies than chemical dissociations. Typically, for a reactive gas, 104 in 106 molecules form free radicals whereas only 1 in 106 ionises. Hence for reactive gases, the predominant plasma effect is from free radicals, but with careful selection of process parameters using noble gases, ionic effects can predominate.

Because plasmas affect materials at an atomic level, it is often necessary to use surface analysis techniques such as scanning electron microscopy and X-ray photoelectron spectroscopy to identify the processes required and to judge their effects. However, as a simple indication of surface energy, and hence adhesion or wetability, a water droplet contact angle test will often suffice. The lower the contact angle, the higher the surface energy and more hydrophilic the material.

Machine Configurations

Machines for plasma processing can be configured according to the product and process. Components can be mounted in trays or baskets or tumbled in a drum, and web or film material can be processed in a reel-to-reel configuration. The electrode design depends upon the product and the process. Where a planar surface is treated, parallel plate electrodes with an unidirectional plasma can be employed. For three dimensional components, electrodes providing an isotropic plasma effect are required.
Disadvantages of other Plasma Processes

Flame, DC corona discharge and atmospheric AC plasma processes are customarily used for surface treatments, and are well suited for continuous production. All, however, have significant limitations for stringent applications. Flame plasmas can cause damage by thermal energy. Corona discharge plasmas tend to have low energy densities and are relatively ineffective, and can cause damage by the accumulation of electrical charge. AC atmospheric plasmas need very high energies, which can damage materials. If a process is conducted in air or in an uncontrolled environment, the treated surfaces can be recontaminated by airborne contaminants or by-products of the process. These processes restrict the free radicals and chemical species available to the surfaces. Dedicated profiled tooling is usually required for simple three dimensional products and none of the processes are suitable for more complex shapes.
Advantages of Vacuum Plasma Processing

The vacuum plasma process avoids damage to materials as it is a controlled, low temperature process with low energy densities. The plasma energy is highly efficient because the vacuum pressure reduces recombinations, and increases the mean free path length of the particles resulting in higher ionic kinetic energies. In the controlled environment of a vacuum plasma, precise surface engineering effects can be achieved with the careful selection of the plasma gases and process parameters. Different gases can be used sequentially to achieve different effects.
Applications

Applications for vacuum plasma process’s are many and varied. Some include:

· Polypropylene automotive components such as car bumpers, door mirror housings and dash board components are plasma treated before painting

· ABS components before the application of wood grain effect transfers

· PTFE surface wetability and bondability is achieved by plasma treatment,thus avoiding the use of hazardous liquid chemistries

· Plasma pretreatment of polyethylene mouldings, with wax and ether inclusions, for adhesion of water-based epoxy adhesives, solvent-based adhesives and electroless copper plating has proved successful. This has replaced a chromic acid process, for health and environmental reasons

· A woven wool and nylon material has been successfully plasma treated in web form for bonding to sheets of natural rubber, forming a composite that is used for waterproof rainwear. Many continuous polymer film materials have been plasma treated in reel-to-reel form for improved adhesion of ink jet printing, surface wetabllity and improved affinity to blood products

· Bacterial, fungal and biological organisms can be removed from medical products using plasma treatment. The strength and reliability of the bond between the needle of a hypodermic syringe and its polypropylene holder is critical. Plasma treating the assembled components in a tumbler before the application of an epoxy adhesive greatly improves the product.

Background

The production of top-quality lightweight alloy wheels as used in the Formula 1 stalls or of alloy rims for conventional passenger cars calls for the strictest requirements with respect to exactness and compliance with the relevant standards. The ZHU250 hardness tester from Zwick meets these demands - exactly.

The ZHU250 universal hardness tester is geared for standards-compliant hardness testing according to Vickers, Brinell, and Rockwell, plus ball-pressure hardness testing to max. 250 kg and is characterized by its intuitive operating concept. The test programs are quick and easy to configure, being largely self-explanatory for both the test bench engineer and the user at the machine. All the settings and parameters are provided in the several languages with a representation that is simple to understand.

Due to the manifold test jobs to be performed, the customer placed highest requirements on the versatility of the testing machine. The Zwick hardness tester was well able to meet these demands primarily due to its large working space (300 x 250 mm). Particularly worth mentioning is that the indentations are measured optically parallaxis- and error-free using a measurement line concept integrated into the focusing screen. This approach ensures high reproducibility of the test results.

With the Zwick ZHU250, for the first time ever a hardness testing machine utilizing the current contents of the DIN EN ISO 18265 standard to enable the revaluation of hardness values has come out on the market. Now, in addition to the conventional tables thus far employed for steels and low-alloy steels and steel castings, the user is provided with standards-compliant revaluation options for materials made from aluminum and copper.

ToughMet is a new spinodal alloy from Brush Wellman. The alloy is composed of 15% nickel and 8% tin and its strength is three times that of copper. It also has tribological properties comparable to those of leaded bronzes.

ToughMet can be used to replace problematic bushings that have previously been made from aluminium, bronze or steel, such as kingpin bushes in large dump trucks for open cast mining.

Background

Titanium was first used in chemical plant in the mid-1960’s. Its outstanding resistance to corrosion in oxidising chloride environments, sea water and other aggressive media were rapidly established. In several processes titanium was the first and only choice for effective plant performance and acceptable levels of life cycle cost.

Performance of Titanium in Various Chemical Environments

Today as shown below titanium is more widely used. Costs of material and fabrication have both stabilised and titanium equipment, properly designed can compete with most of the more common but usually less effective corrosion resistant alloys.

Table 1. Process media where titanium’s oxide film is stable (within operating boundaries).

Environment	Performance
Chlorine and chlorine compounds	a. Moist chlorine gas b. water solutions of chlorites, hypochlorites, perchlorates and chlorine dioxide c. Chlorinated hydrocarbons and oxychloro compounds
Other halogens	a. Bromine; moist gases, aqueous solutions and compounds b. Iodine; moist gases and compounds
Water	a. Fresh water, steam b. River water c. Seawater d. Water containing organisms that cause biofouling e. Water containing micro-organisms that would typically cause microbiologically influenced corrosion in other materials of construction
Oxidising mineral acids	a. Nitric b. Chromic c. Perchloric d. Hypochlorous (wet chlorine gas)
Inorganic salt solutions	a. Chlorides of such minerals as sodium, potassium, magnesium, calcium, copper, iron, ammonia, manganese, nickel b. Bromide salts c. Sulfides, sulfates, carbonates, nitrates, chlorates, hypochlorites
Organic acids	a. Acetic b. terephthalic c. Adipic d. Citric (aerated) e. Formic (aerated) f. Lactic g. Stearic h. Tartaric i. Tannic
Organic chemicals (with moisture or oxygen)	a. Alcohols b. Aldehydes c. Esters d. Ketones e. Hydrocarbons
Gases	a. Sulfur dioxide b. Ammonium c. Carbon dioxide d. Carbon monoxide e. Hydrogen sulfide f. Nitrogen
Alkaline Media	a. Sodium hydroxide b. Potassium hydroxide c. Magnesium hydroxide d. Ammonium hydroxide

Fabrication Costs

Fabrication costs for titanium pressure vessels are surprisingly lower than for some other widely used corrosion resistant alloys.

ToughMet is a new spinodal alloy from Brush Wellman. The alloy is composed of 15% nickel and 8% tin and its strength is three times that of copper. It also has tribological properties comparable to those of leaded bronzes.

ToughMet can be used to replace problematic bushings that have previously been made from aluminium, bronze or steel, such as kingpin bushes in large dump trucks for open cast mining.

Table 1 provides a direct comparison of physical, thermal and electrical properties of pure titanium with other metals such as 304 stainless steel, aluminium, magnesium, nickel and copper.

Table 1. Comparison of physical properties of titanium with those of other metals

Property	Titanium	304 Stainless Steel	Aluminium	Magnesium	Nickel	Copper
Atomic No.	22	--	13	12	28	29
Atomic Wt.	47.9	--	26.97	24.32	58.69	63.57
Specific Gravity	4.5	7.9	2.7	1.7	8.9	8.9
Linear thermal expansion coefficient (/°C)	8.4X10-6	17X10-6	23X10-6	25X10-6	15X10-6	17X10-6
Specific heat (cal/gr/°C)	0.124	0.12	0.21	0.24	0.11	0.092
Thermal conductivity coefficient (cal/cm2/sec/°C/cm)	0.041	0.039	0.49	0.38	0.22	0.92
Specific electrical resistance (µOhm-cm)	55	72	2.7	4.3	9.5	1724
Electrical conductivity (%IACA)	3.1	2.4	64	40	18	100
Young's modulus (kg/mm2)	10850	20403	7050	4570	21000	11000
Poisson's ratio	0.34	0.3	0.33	0.35	0.30	0.34

Background

Titanium was first used in chemical plant in the mid-1960’s. Its outstanding resistance to corrosion in oxidising chloride environments, sea water and other aggressive media were rapidly established. In several processes titanium was the first and only choice for effective plant performance and acceptable levels of life cycle cost.

Performance of Titanium in Various Chemical Environments

Today as shown below titanium is more widely used. Costs of material and fabrication have both stabilised and titanium equipment, properly designed can compete with most of the more common but usually less effective corrosion resistant alloys.

Table 1. Process media where titanium’s oxide film is stable (within operating boundaries).

Environment	Performance
Chlorine and chlorine compounds	a. Moist chlorine gas b. water solutions of chlorites, hypochlorites, perchlorates and chlorine dioxide c. Chlorinated hydrocarbons and oxychloro compounds
Other halogens	a. Bromine; moist gases, aqueous solutions and compounds b. Iodine; moist gases and compounds
Water	a. Fresh water, steam b. River water c. Seawater d. Water containing organisms that cause biofouling e. Water containing micro-organisms that would typically cause microbiologically influenced corrosion in other materials of construction
Oxidising mineral acids	a. Nitric b. Chromic c. Perchloric d. Hypochlorous (wet chlorine gas)
Inorganic salt solutions	a. Chlorides of such minerals as sodium, potassium, magnesium, calcium, copper, iron, ammonia, manganese, nickel b. Bromide salts c. Sulfides, sulfates, carbonates, nitrates, chlorates, hypochlorites
Organic acids	a. Acetic b. terephthalic c. Adipic d. Citric (aerated) e. Formic (aerated) f. Lactic g. Stearic h. Tartaric i. Tannic
Organic chemicals (with moisture or oxygen)	a. Alcohols b. Aldehydes c. Esters d. Ketones e. Hydrocarbons
Gases	a. Sulfur dioxide b. Ammonium c. Carbon dioxide d. Carbon monoxide e. Hydrogen sulfide f. Nitrogen
Alkaline Media	a. Sodium hydroxide b. Potassium hydroxide c. Magnesium hydroxide d. Ammonium hydroxid

Fabrication Costs

Fabrication costs for titanium pressure vessels are surprisingly lower than for some other widely used corrosion resistant alloys.