Search results

The rheological properties of a coating are important determinants of storage, application and flow characteristics and, as such, the need for its accurate measurement is an important requirement in formulation development. Measurement of rheology is also an important phase of quality control testing, though frequently less sophisticated, more rapid, characterisation techniques may sometimes be used here. This article will consider some of the literature concerned with techniques of measuring coating rheology.

Unquestionably, mercury‐based products during their many years of use in the paint industry have provided an answer to most of the microbiological problems encountered.

The purpose of this study was to determine correlation between an accelerated cyclic corrosion test (S6‐cycle test) specified in Japanese Industrial Standards K5621 and field exposure tests, and to open up applications of the accelerated tests in various regional environments.

The S6‐cycle corrosion test was carried out on structural steels for 30, 60, 90, 120 and 150 days and metal coating films for 100, 200 and 300 days. Comparing the weight loss of the steels with 1‐, 3‐, 5‐ and 9‐year field exposure test data at 31 sites in Japan. Correlation of the S6‐cycle tests to the field exposure tests was determined by acceleration coefficients.

The correlation between the S6‐cycle test and the field test on uncoated structural steels can be determined by acceleration coefficients based on flying salt amount. The coefficients were applicable for durability prediction of uncoated, zinc hot‐dip galvanized and painted steels.

In determination of the accelerated coefficients, only the flying salt amount was considered. Others factors such as temperature and humidity will be considered in future work.

Using the S6‐cycle corrosion test and its accelerated coefficients, the thickness loss of uncoated structural steels and zinc hot‐dip galvanizing is predictable in a short time. Corrosion degradation of coated steels is also predictable approximately.

This paper contributes to open up the application of accelerated cyclic corrosion test to evaluating corrosion resistance of steel bridge members.

Silica waste fume is a byproduct produced in the manufacture of ferrosilicon. The sample, which was very fine and rich in silica, was characterized using chemical and spectrophotometric measurements (XRD and electron microscope). The silica fume was incorporated in anticorrosive paint formulations based on alkyd resin to replace partially or completely the imported diatomaceous silica. The various paint formulations were evaluated and the physico‐mechanical properties as well as the corrosion protection properties of the painted films have been studied. Promising results were achieved, which showed that silica fume can replace satisfactorily the imported diatomaceous silica from the economical and environmental points of view.

The purpose of this paper is to reduce the amount of copper in antifouling paints by using eugenol as an additive. Biofouling leads to deterioration of any submerged material. The most widespread method for control is the application of cuprous oxide antifouling paints which are toxic. First of all, the paper describes the effect of eugenol on larvae of Balanus amphitrite (fouling organism) under laboratory conditions and then the preparation, application and performance of different types of antifouling paints in field trials.

Three types of soluble matrix antifouling paints were prepared with different pigments. The first one containing 16 per cent v/v copper, the second with 1.6 per cent copper and the third with 1.6 per cent copper + 2 per cent eugenol.

After 12 months of immersion in Mar del Plata harbour paints containing 1.6 per cent copper + eugenol and 16 per cent copper were the most effective. Although these formulations showed a similar performance, copper + eugenol-based paint contains 90 per cent lesser copper than a traditional copper-based formulation.

The use of antifouling paints with copper + eugenol combination as pigment is a promising alternative due to its performance, low cost and reduction in copper leaching to environment.

To synthesise anticorrosion pigments of a lamellar and core‐shell type based on Zn, Ca and Mg ferrites for metal protecting paints.

The anticorrosion pigments were synthesised from oxides or carbonates at high temperature. The pigments synthesised had particles with a pronounced lamellar‐tubular shape consisting of MgFe₂O₄; Mg_0.8Zn_0.2Fe₂O₄; Mg_0.6Zn_0.4Fe₂O₄; Mg_0.4Zn_0.6Fe₂O₄; Mg_0.2Zn_0.8Fe₂O₄; ZnFe₂O₄; Ca_0.2Zn_0.8Fe₂O₄; and CaFe₂O₄. The other type of synthesised ferrite pigments were core‐shell anticorrosion pigments where a layer corresponding to the compositions including MgFe₂O₄/KAl₃Si₃O₁₁; Mg_0.8Zn_0.2Fe₂O₄/KAl₃Si₃O₁₁; Mg_0.6Zn_0.4Fe₂O₄/KAl₃Si₃O₁₁; Mg_0.4Zn_0.6Fe₂O₄/KAl₃Si₃O₁₁; Mg_0.2Zn_0.8Fe₂O₄/KAl₃Si₃O₁₁; ZnFe₂O₄/KAl₃Si₃O₁₁; Ca_0.2Zn_0.8Fe₂O₄/KAl₃Si₃O₁₁; and CaFe₂O₄/KAl₃Si₃O₁₁ was applied onto the core – white mica – by a chemical reaction. The pigments prepared were characterised by means of X‐ray diffraction analysis, particle size distribution measurement, and scanning electron microscopy. The anticorrosion pigments synthesised were used to formulate alkyd paints that were tested in corrosion atmospheres.

Lamellar particles were detected in the pigments prepared, whereas quality coverage of the core was identified in the core‐shell ferrites. Good anticorrosion efficiency was detected in all of the pigments synthesised.

The pigments synthesised can be conveniently utilised in paints to protect metal bases from corrosion.

The method of using the ferrites synthesised as metal protecting anticorrosion paints is new. Of great benefit are the application and the method of synthesising the anticorrosion pigments that do not contain any heavy metals and are environmentally friendly.

Examines accelerated methods for the corrosion testing of materials, coatings and surface treatments used in the aerospace and defence industries. The drawbacks with some current accelerated corrosion tests are examined, particularly the problems experienced with neutral salt spray tests. Specific examples are given which identify the acute discrepancy between salt spray and marine exposure in the corrosion testing of metallic coatings on steels. Examines some recent advances in corrosion testing of aerospace materials, pre‐treatments and organic coatings, and outlines some preliminary research conducted at DERA Farnborough in developing more accurate test methods.

Summary The present work aims to study the inhibition mechanism of barium metaborate pigments. Six grades of barium metaborate pigments were prepared in the Laboratory of Polymers and Pigments, National Research Centre of Cairo, Egypt. The methods of preparation modification and evaluation is the main subject of a recent article. The pigments were incorporated, with other ingredients, into formulations, and the electrode potential, electrical resistance, water uptake and weight loss measurements were taken. Formulations based on a commercial pigment supplied by an international company were prepared and used as blanks.

Steel structures have often been painted with good, unbroken films which have lasted as long as ten years without repainting, in reasonably dry and unpolluted areas. To endeavour to reach such an ideal state on the steel structures and plants which are essential features of a large integrated steelworks is a much more costly and difficult process. It must be appreciated that much of the plant engaged in or ancillary to the production of iron and steel operates continuously with very few shutdown periods for maintenance. This is particularly true of the coke‐oven and by‐products plants and unfortunately much of the corrosion at steelworks is due to the operating conditions which are necessary for the continuous production of coke. In this article the maintenance painting of steelworks in similar conditions is described.

This study aims to synthesize a series of new anticorrosive pigments using a new technique called “core-shell”. This technique is based on depositing thin surface layer of expensive, efficient anticorrosive pigment on a cheap extender. This extender forms the bulk of the new pigments. The new pigments were constructed on cores of either waste silica fume or kaolin comprising 80-85 per cent of their chemical structure, and the ferrite shell was about of 20-15 per cent. Electrochemical studies were undertaken on two series of pigments for comparison between ferrites/silica fume and ferrites/kaolin pigment to show their performance, as the shells are different.

The different ferrites/silica fume and ferrites/kaolin pigments were characterized using different analytical and spectrophotometric techniques, such as X-ray fluorescence (XRF) and transmission electron microscopy (TEM). Immersion test and electrochemical impedance measurements were done in 3.5 per cent NaCl.

The tests revealed that paint films containing Sr ferrite/silica and Ca ferrite/kaolin were the most effective in corrosion prevention.

Silica fumes have a large array of uses. These pigments can be applied in various industries such as painting, wooding coating, anti-corruption coating, powder coating, architectural paint and waterproof paints. Treated kaolin can be applied in many industries besides pigment manufacture and paint formulations; it can be applied as a reinforcing filler in rubber, plastics and ceramic composites.

The new pigments are considered ecofriendly materials, because using them converts a waste product and a natural ore to useful marketable product, leading to reducing cost and saving the environment at the same time.