Painted Metal Research Articles

Engelhard launches new orange pigments

Engelhard Corp has introduced a new non-heavy metal, weather-fast and heat-stable orange pigment, which is claimed to provide a cost-effective alternative to molybdate orange in formulations where it is desirable to remove the heavy-metal pigment while maintaining its properties. Synergy ™ Orange 6113 is a mid-shade orange that has enough heat stability and weather-fastness to be used in most polymers for exterior applications, Engelhard says. Examples include wire and cable, construction fencing and barriers, and tool housings. Accelerated weathering studies conducted in the company’s laboratories have shown that the new pigment has excellent weather-fastness. This is a short news story only. Visit www.addcomp.com for the latest additives and compounding industry news

US: Eckart — metallic pigments for inks

US: Eckart — metallic pigments for inks

Interactions of Atlantic salmon in the Pacific northwest: V. Human health and safety

The paper discusses potential issues for human health and safety from net-pen salmon farming in the Pacific northwest region. A brief introduction to global and national responsibilities for food safety is followed with a review of the chemicals and chemical contaminants in materials used in farm production operations. Possible sources include metallic paints, feed ingredients, and chemotherapeutants. Concerns for the transmission of diseases follow, and the common pathogenic diseases are reviewed. After a section on the processing and quality of farm products, specifically the proximate composition of farm fish and differences between farm and wild salmon species, the concerns for worker safety on the farm are considered. The paper ends with some conclusions on the varying degrees of risk carried by these issues.

Effect of painting work on alcoholic liver dysfunction

The effect of painting on alcoholic liver dysfunction was investigated. The subjects were male workers engaged in small-scale enterprises under contract to with heavy industries. Painting involved metal cleaning and painting, and the air concentrations of organic solvents were frequently high. The study population consisted of 1,157 male workers over 40 yr of age. Of them, 85 were painters engaged for a mean duration of 20.9 +/- 9.8 yr. There was no significant difference in GOT and GPT between painters who did not drink and non-painters who did not drink, but GOT and GPT were significantly higher in painters drinking several days a week than in non-painters. A past history of hepatitis affected GOT, GPT and gamma-GTP. Painting, daily alcohol consumption, drinking frequency and body mass index affected gamma-GTP. A questionnaire survey of hepatitis was also conducted in 206 male workers (age range 18-67 yr). Of them, 134 were painters (mean duration of painting, 16.8 +/- 10.4 yr). This questionnaire survey showed that 13 painters (9.6% of the painters) and two non-painters (2.6% of the non-painters) had a history of hepatitis. Of the 13 painters, five painters had a history of hepatitis C and four had a history of alcoholic hepatitis. All of these 13 painters had the habit of drinking. This study indicated that painting had little effect on the liver function in painters not drinking, but increased alcoholic liver dysfunction in painters with the drinking habit.

The Characterization of Metal Soaps

To characterize more fully the metal soaps found in paint films or on metal surfaces, several metal soaps were synthesized and their X-ray diffraction pattern and Fourier transform infrared (FTIR) and Raman spectra measured. Metal soaps were obtained from four different fatty acids found in drying oils — two saturated (palmitic and stearic acids) and two unsaturated (oleic and linoleic acids) — and from copper, zinc and lead, three metals that are typically found in metal alloys and paint systems. Data are reported for the following compounds: palmitic acid, stearic acid, oleic acid, linoleic acid, zinc palmitate, zinc stearate, zinc oleate, zinc linoleate, copper palmitate, copper stearate, copper oleate, lead palmitate, lead stearate and lead oleate. Features that are characteristic of specific compounds were observed. Soaps obtained from different fatty acids with the same metal ion show differences, as do soaps obtained with the same fatty acid but with different metal ions. Identification is key to understanding how and why metal soaps form on actual objects, and this may lead to preventive measures.

Mid-IR transmission window for corrosion detection beneath paint

The mid-infrared transmission window between 3.8–5.5 µm has been used to detect corrosion beneath a paint layer of 80–100 µm thickness using low power light emitted diodes. Two-dimensional images from a sample of painted metal with corrosion were obtained for 3.8 to 5.5 µm wavelengths. The best contrast for imaging corrosion is near 4.8 µm.

Coloured paints based on iron oxide and silicon oxide coated flakes of aluminium as the pigment, for energy efficient paint: optical and thermal experiments

Energy efficient coloured paint coatings utilising flaky aluminium pigment with either single layer (Fe2O3) or double layer (Fe2O3 on SiO2) interference coatings are optically and thermally characterised. Similar pigments with coatings on flaky dielectric particles and standard paints of similar colour are compared. Data presented includes hemispherical and specular reflectance spectra across visible and infra red wavelengths, thermal emittance from an emissometer and light spreading data from a photogoniometer. Solar absorptance, and colour show that, as theoretically predicted, and provided flaky metal pigments are used, a wide range of colours combined with a much lower solar absorptance than traditional paints of similar colour is achieved. Superior thermal performance to ordinary paints with similar colour is thus possible and is demonstrated for two such coloured layers via controlled heating-cooling studies under both an indoor lamp and outdoor clear sky solar illumination. It is seen that heat gains from the sun and associated cooling loads can be reduced by up to 50% for most colours, which is of some benefit for cars and metal roofs in hot climates.

MD-Both names sales agents for its metallic pigments & carbon black dispersions

MD-Both names sales agents for its metallic pigments & carbon black dispersions

Characterising special-effect colours

Special-effect colours, such as those produced by coatings containing metallic and mica pigments, have rapidly grown in popularity over the last 50 years. Originally used to give glamorous metallic effects on top-of-the-range cars, they are now widely used in products such as cosmetics, mobile phones and packaging materials.

Revisión de las aplicaciones de la electroerosión por penetración al mecanizado de cerámicas conductoras

The term of technical ceramics or advanced ceramics is applied to a great emerging variety of materials, which have excellent properties such as hardness, wear resistance, corrosion resistance, mechanical strength, in a wide range of temperature , among others. Nevertheless, materials with high quality performance are also difficult to manufacture, and ceramic materials are not the exception. The majority of the ceramic materials are not conductive, but however, the use of new metallic pigments and compounds makes it feasible to become them conductive and, therefore, these ceramics can be machined by the EDM process. The present work is a review of the different applications of technical ceramics, concentrating on the conductive ceramics. Moreover, the machining processes that can be employed for their manufacturing are to be shown, focusing attention on the die sinking EDM process.

Case Study: Color Control in the Automotive Industry

Numerous manufacturers are concerned with ensuring the homogeneity in the colors of different parts that compose their products. This quality objective of primary importance is especially challenging when the parts are sourced by different suppliers. The technical difficulties are accentuated when metallic or pearly paints are used since the presence of metallic chips in the paint causes a variation in the color according to the angle of observation. Also, the development of metametric colors increases these difficulties even more, as these colors are sensitive to different illumination sources. The present study relates to the production of colored car bumpers. By using a spectrocolorimeter and color samples, the process is improved to better respect the customer specifications. To achieve this, critical colors and significant parameters affecting colors are identified, design of experiments is used to optimize the process settings, and a correlation study allows further process improvement. The results achieved are impressive: the quality index used has been improved by 67% in only 6 months. This case study therefore illustrates how simple quality tools can be used in a rigorous search for process improvement toward total color mastering with zero defect objective.

Corrosion inhibited metal pigments

Flake-shaped particles of aluminium are well known in the coatings and printing ink industry as “silver bronze pigments”. For their use in waterborne coatings or outdoor applications, an effective corrosion protection of the highly reactive aluminium surfaces is required. The traditional stabilization techniques for aluminium pigments are based on the addition of corrosion inhibitors or on chromate passivation. This publication presents new developments in the encapsulation of metallic pigments that are based on modern sol-gel techniques. All products are heavy metal-free and provide excellent applicational properties.

THE STUDY OF ANGLO-SAXON ILLUMINATED MANUSCRIPTS FROM THE BRITISH LIBRARY COLLECTION USING RAMAN MICROSCOPY

THE STUDY OF ANGLO-SAXON ILLUMINATED MANUSCRIPTS FROM THE BRITISH LIBRARY COLLECTION USING RAMAN MICROSCOPY

Effect of warship impressed current cathodic protection configuration on low frequency current output modulations associated with propeller/shaft rotation

Physical scale modelling was employed to examine the effect of reference electrode (RE) location upon the modulations of warship impressed current cathodic protection (ICCP) current output resulting from propeller rotation. A one hundredth scale painted metal model of a frigate hull, fitted with two rotating propellers, was protected by ICCP in sea water diluted to an electrical conductivity one hundredth that of standard sea water. An 'all aft' four anode ICCP configuration was employed, with the RE at one of three locations in the after cut up. Propeller/shaft rotation produced amplitude modulations of ICCP current outputs. The data shows that both the waveform and the magnitude of the modulations were determined by where the RE was sited relative to the propellers. A different output waveform was associated with each RE location. A superimposed 'beat' rhythm was produced only with one position. The RE location also determined not only total current outputs but also the absolute and percentage magnitude of the modulations. Possible mechanisms for the phenomenon and requirements for further studies are discussed.

Ranking high-quality paint systems using EIS. Part II: defective coatings

The assessment of the protective performance of paint coating systems as described in Part I of this work is a valuable procedure for intact coatings. However when defects are present in the paint films the significance of tests using intact coatings is limited, since the mechanisms involved in degradation/healing of the painted metal could change. Thus the full knowledge of the degradation behaviour of coated metals should involve both situations, requiring the use of the two types of specimens, i.e., with intact and defective coatings. In order to meet the industry requirements in terms of time, accelerated cabinet tests in scribed coated specimens can be associated with intermediate temperature tests in intact coatings using EIS measurements (Part I).

Cluster demagnetizing effects in particulate dispersions

We describe a study of a dispersion of metal pigments. We have used a high field pulsed magnetometer to examine the acquisition of remanence and have observed anomalous behavior as a function of both the magnitude of the pulsed field and its duration. The remanence increases monotonically until a critical field or a critical time is reached and then suddenly decreases at a highly reproducible value of field, and then subsequently increases when a larger pulsed field is applied. At very high fields a second drop in remanence is observed. By comparison with a computer simulation we infer that this behavior may arise due to strong demagnetising dipolar interactions in aggregates of a certain critical size.

Lead in candle emissions

The candle-using public should be made aware that the core of candle wicks may contain lead. Used as a stiffening agent to keep the wick out of the molten wax, lead can be emitted as particulates to the air and then deposited on indoor surfaces. To define the problem, 100 sets of candles (two or more identical candles) were purchased locally. The criterion for purchase was that the candles must appear to contain a metal-cored wick or be covered by a metallic pigment. Of the candles purchased, 8% contained lead wicks. The wicks were 39–74% lead (the remainder was fabric or paper) and the lead cores (approx. 100% lead) had linear densities of 13–27 mg/cm. Candles were burned to completion in a closed chamber to capture the air emissions, and the candle residue was extracted to assess the lead mass balance. It was found that individual candles emitted lead to the air at average rates that ranged from 100 to 1700 μg/h. Assuming realistic indoor conditions, these emission rates were modeled to project room air concentration, child exposure by inhalation, and indoor deposition. Results showed that burning single candles can easily raise the source room concentration above the ambient air lead concentration limit of 1.5 μg/m 3 set by EPA. Burning multiple candles can elevate it above OSHA permissible exposure limits of 50 μg/m 3. Although blood lead levels have dropped precipitously in the United States since lead was phased out of gasoline in 1986, nearly 900 000 children still had levels above 10 μg/dl during NHANES III. Considering that candle sales in the US are estimated at $1–2 billion per year, and that children may spend as much as 88% of their time indoors, it is reasonable to suspect that some blood lead elevation in children arises from indoor micro-environments where lead-wick candles are burned.

X-ray powder diffraction data for selected metal soaps

In order to better characterize metal soaps found in paint films or on metal surfaces, several metal soaps were synthesized and their X-ray powder diffraction patterns measured. Metal soaps were obtained from four different fatty acids found in drying oils, two saturated (palmitic and stearic acids) and two unsaturated (oleic and linoleic acids), and from copper, zinc, and lead, three metals that are typically found in metal alloys and paint systems. X-ray powder diffraction data are reported for the following compounds: palmitic acid, stearic acid, zinc palmitate, zinc stearate, zinc oleate, zinc linoleate, copper palmitate, copper stearate, copper oleate, lead palmitate, lead stearate, and lead oleate. Features that are characteristic of specific compounds were observed. Soaps obtained from different fatty acids with the same metal ion show differences, as do soaps obtained with the same fatty acid but with different metal ions. Differences were observed when X-ray powder diffraction data obtained for stearic acid and zinc stearate were compared to published data for these two compounds (PDF 38-1923 and 5-0079, respectively). In the case of stearic acid, differences could be explained by the fact that the specimen reported previously in PDF 38-1923 was likely contaminated with palmitic acid. In the case of zinc stearate, low angle data were missing from the original pattern PDF 5-0079 and peaks that were reported in other angular regions in fact consisted in more peaks that were not resolved due to broadening.

Analysis of metallic pigments by ion microbeam

Metallic paints consist of metallic flakes dispersed in a resinous binder, i.e. a light-element polymer matrix. The spatial distribution and orientation of metallic flakes inside the matrix determines the covering efficiency of the paint, glossiness, and its angular-dependent properties such as lightness flop or color flop (two-tone). Such coatings are extensively used for a functional (i.e. security) as well as decorative purpose. The ion microbeam analysis of two types of silver paint with imbedded metallic flakes has been performed to determine the spatial distribution of the aluminum flakes in paint layer. The average sizes of the aluminum flakes were 23 μm (size distribution 10–37) and 49 μm (size distribution 34–75), respectively. The proton beam with the size of 2×2 μm 2 at Ljubljana ion microprobe has been used to scan the surface of the pigments. PIXE mapping of Al Kα map shows lateral distribution of the aluminum flakes, whereas the RBS slicing method reveals tomograms of the flakes in uppermost 7 μm of the pigment layer. The series of point analysis aligned over the single flake reveal the flake angle in respect to the polymer matrix surface. The angular sensitivity is well below 1 angular degree.

Meeting the challenge of radical change

The coating industry has only occasionally been presented with the challenges and opportunities which either bring about, or proceed from, radical change—the advent of latex house paints, powder coatings and electrodeposition have been among the very few. Today, however, the coatings R&D community is blessed/cursed with a large variety of potential technology approaches, any of which—solid paint, solventless liquids, energy-curing systems, the use of nanotechnology or combinatorial chemistry, et al.—might lead to paradigm-shifting products and processes. It is easy to envision a future in which painted metal might replace asphalt shingles, claytiles, and other common roofing materials widely used on residential roofing, and the automotive industry is clearly willing to explore coil-applied alternatives to its current painting practices. Taking advantage of the opportunities implicit in these new technologies, processes, and markets which are on the horizon will, however, require both new approaches to early performance prediction and also a renewed commitment to—and funding of—R&D within the global coatings community.