Paints and the Part they Play in the Fight Against Corrosion. H. Hollis, B.SC., A.R.I.C., and L. J. COLEMAN (Chemical Inspectorate, Ministry of Supply). Dr. W. F. Higgins…
Abstract
Paints and the Part they Play in the Fight Against Corrosion. H. Hollis, B.SC., A.R.I.C., and L. J. COLEMAN (Chemical Inspectorate, Ministry of Supply). Dr. W. F. Higgins (Magnesium Elektron Ltd.) stated that the importance of surface preparation could not be too greatly stressed. Continuing, he said that the authors had made what seemed to him to be an extraordinary statement, although up to a point it was really common sense. They had said that a primer was applied to protect the metal surface, and then the top coat or maybe the intermediate coat was applied to protect the primer. He gathered they were not referring to protection merely against physical damage. But why did they do that? It should not be necessary. On the previous day it was stated by Mr. Rogers that it was done because the ratio of binder to solid was small, and therefore there was not good adhesion. Dr. Higgins suggested that, if a primer were applied to the metal surface and it had not good adhesion, one could not make it good by putting another coat of paint on top of it.
CATHODIC protection is complementary to the physical protection of metals, since it is used in conditions where painting and similar methods are not practicable, or not wholly…
Abstract
CATHODIC protection is complementary to the physical protection of metals, since it is used in conditions where painting and similar methods are not practicable, or not wholly satisfactory; in the case of metals which are buried in damp ground or immersed in aqueous fluids. The underlying principle is that, if metal surfaces in need of protection can be made completely cathodic, no corrosion will occur. This is effected by the introduction of an artificial anode which sets up a flow of current, the circuit of which is completed by the aqueous medium acting as the electrolyte.
MAGNESIUM, because of its low density, has obvious possibilities as an aircraft structural material. The useful magnesium alloys have densities in the range 1·76 to 1·83, compared…
Abstract
MAGNESIUM, because of its low density, has obvious possibilities as an aircraft structural material. The useful magnesium alloys have densities in the range 1·76 to 1·83, compared with the aluminium alloys range of about 2·5 to 2·8. The melting point of magnesium is 650 deg. C., almost identical with that of aluminium (660 deg. C.), so that generally the alloys of each of these base elements have applications in much the same temperature band.
Much misunderstanding exists about the relationship between tables of normal electrode potentials and the galvanic series of the metals on the one hand, and the possibilities of…
Abstract
Much misunderstanding exists about the relationship between tables of normal electrode potentials and the galvanic series of the metals on the one hand, and the possibilities of galvanic or bimetallic corrosion on the other. It is too often assumed that a direct relationship exists and that the corrosion behaviour of a pair of metals can be predicted from the potential difference between them. This article briefly evaluates the position.
Zinc coatings are applied commercially by hot‐dipping, electro‐deposition, metal‐spraying, cementation and vacuum deposition (see Table 5). Galvanizing (zinc hot‐dipping) has been…
Abstract
Zinc coatings are applied commercially by hot‐dipping, electro‐deposition, metal‐spraying, cementation and vacuum deposition (see Table 5). Galvanizing (zinc hot‐dipping) has been done for more than 200 years now and is undoubtedly the most widely‐used form of metal coating. The production and pro‐perties of these coatings have received intensive study over the last 10 years; much of this has been reported at the ‘International Conferences on Hot‐Dip Galvanizing’.
CAR CORROSION HAZARDS. IN this issue we present the first of a series of three articles on corrosion in the motor car by a scientist of the Motor Industry Research Association. In…
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CAR CORROSION HAZARDS. IN this issue we present the first of a series of three articles on corrosion in the motor car by a scientist of the Motor Industry Research Association. In this first article he discusses corrosive wear of piston rings and cylinders. Other aspects, including corrosion of the cooling system, will be dealt with later. The size of the cooling system problem may be gauged from the fact that in the U.S. something like 700,000 radiators have to be replaced each year owing to corrosion damage caused by antifreeze chemicals. In addition, an even greater number of cooling system ancillaries such as thermostats and water pumps have to be replaced. The best makes of antifreeze contain a corrosion inhibitor. In practice, however, minerals in the water, corrosive exhaust gases from a leaky cylinder‐head gasket and even air seeping into the cooling system eventually destroy the inhibitor's effectiveness. Frequent replacement of antifreeze is advisable until more effective corrosion‐prevention methods are devised.
Continuing from last month, the development and choice of materials for giving the best protection are discussed—galvanic anodes, anodes for use with impressed current and…
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Continuing from last month, the development and choice of materials for giving the best protection are discussed—galvanic anodes, anodes for use with impressed current and graphite anodes. A survey of the applications and limitations of cathodic protection is also included.
THE Loyal Toast having been honoured, the Chairman extended a welcome to all the delegates, who came from the four corners of the earth, to the Convention and the Exhibition. It…
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THE Loyal Toast having been honoured, the Chairman extended a welcome to all the delegates, who came from the four corners of the earth, to the Convention and the Exhibition. It was the first of its kind anywhere in the world to deal with, to combat and, if possible, to cure corrosion.
The high‐temperature corrosion tester described in this article has been used to establish the characteristics of the cooling water source to be used at English Steel…
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The high‐temperature corrosion tester described in this article has been used to establish the characteristics of the cooling water source to be used at English Steel Corporation's new Tinsley, Sheffield, project, and will also be used at Shell Chemical Co.'s establishment at Partington, nr. Manchester.
Rust‐proofing material. An improved rust‐proofing, non‐gelling bituminous material comprises an oxidised cut‐back asphalt containing a minor proportion of an aliphatic primary…
Abstract
Rust‐proofing material. An improved rust‐proofing, non‐gelling bituminous material comprises an oxidised cut‐back asphalt containing a minor proportion of an aliphatic primary amine or mixture of amines with 16 to 18 C atoms in the C chain and a minor proportion of a fatty acid of 15 to 19 C atoms in the alkyl radical.—Brit. Pat. 700,146, Standard Oil Development Co.