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Explains corrosion protection and how it works. Discusses the effect of environmental legislation on corrosion protective paints, which necessitates the removal of…
Explains corrosion protection and how it works. Discusses the effect of environmental legislation on corrosion protective paints, which necessitates the removal of solvents and toxic additives, making the protection weaker. In order to remedy this one must determine how protection is provided, which involves the separation of barrier properties and electrochemical passivation. Describes methods and tests involved in this and discusses the results. Concludes with recommendations and a suggestion for further tests.
The prevention of corrosion in the structures, engines and ancillary equipment of aircraft presents the corrosion engineer with a unique problem of the severest magnitude. Failure to provide adequate protection under all conditions will produce catastrophic results or, assuming that the affected parts are discovered in time, a costly replacement scheme.
Examines accelerated methods for the corrosion testing of materials, coatings and surface treatments used in the aerospace and defence industries. The drawbacks with some…
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.
ALUMINIUM alloys have been important structural materials in aircraft from very early days, and there is no doubt that the course of aeronautical development would have…
ALUMINIUM alloys have been important structural materials in aircraft from very early days, and there is no doubt that the course of aeronautical development would have been very different without them. It would be pointless to review the classification of these alloys and their respective fields of application in quite the same way as was done in the two previous articles of this series, those on titanium and magnesium. The aircraft industry has used many of the traditional alloys for years, and is highly familiar with their possibilities and limitations. In this article we shall outline, in the first place, the extent of present alloy development, giving some special attention to matters of particular aeronautical significance, and then limit further consideration to certain specific types of alloy which, for one reason or another, are the most promising as well as being the most difficult to use successfully in aircraft structures. These alloys are all of the high‐strength precipitation‐hardening type.
This paper seeks to summarise the results of available research on the use of high velocity oxy‐fuel (HVOF) thermal‐spray technique to provide protection against high…
This paper seeks to summarise the results of available research on the use of high velocity oxy‐fuel (HVOF) thermal‐spray technique to provide protection against high temperature corrosion and erosion‐corrosion of materials.
This paper describes one of the recent thermal‐spray processes, namely HVOF thermal‐spray technology and presents a survey of the studies on the use of this technique to provide protection against corrosion and erosion‐corrosion of high temperature alloys, with a special emphasis on boiler steels.
High temperature corrosion and erosion‐corrosion are serious problems observed in steam‐powered electricity generation plants, gas turbines, internal combustion engines, fluidized bed combustors, industrial waste incinerators and recovery boilers in paper and pulp industries. These problems can be prevented by changing the material or altering the environment, or by separating the component surface from the environment. Corrosion prevention by the use of coatings for separating materials from the environment is gaining importance in surface engineering. Amongst various surface modifying techniques, thermal spraying has developed relatively rapidly due to the use of advanced coating formulations and improvements in coating application technology. One of the variants of thermal spraying, namely HVOF has gained popularity in recent times due to its flexibility for in‐situ applications and superior coating properties.
This review covers mainly information that has been reported previously in the open literature, international journals and some well‐known textbooks.
The paper presents a concise summary of information for scientists and academics, planning to start their research work in the area of surface engineering.
This paper fulfils an identified information/resources need and offers practical help to an individual starting out on a career in the area of surface engineering for erosion‐corrosion and wear.
The aerospace industry relies heavily on protective treatments and processes to ensure that the structural integrity of an aircraft is not degraded in service as a result…
The aerospace industry relies heavily on protective treatments and processes to ensure that the structural integrity of an aircraft is not degraded in service as a result of operating under harsh corrosive conditions. Many of the chemicals and processes currently employed in metal finishing have been found to cause pollution and long‐term damage to the environment. Legislation and international agreements are now in place which ultimately will lead to a ban or major reduction in the use of many of these processes and coatings. The aircraft constructors and operators are seeking to adopt new protective schemes and treatments which will satisfy future environmental requirements.
From November 29 to December 2 the Empire Hall at Olympia, London, will be given over to what will probably be the world's largest display of products, processes and…
From November 29 to December 2 the Empire Hall at Olympia, London, will be given over to what will probably be the world's largest display of products, processes and services for use in the prevention or limitation of corrosion. Over 120 stands will be shared by 94 exhibitors, each contributing in some way or in many ways to this cause. The extensive preview in the following pages is divided into sections. However, the grouping is general and reflects only one aspect of a company's activities. Therefore a complete examination of items is recommended.
Traditionally aerospace coatings have been formulated for performance. In an extreme case a faulty coating could contribute to an accident on a catastrophic scale. The…
Traditionally aerospace coatings have been formulated for performance. In an extreme case a faulty coating could contribute to an accident on a catastrophic scale. The demands on aerospace coatings are severe because aircraft have unusual requirements. These requirements are dictated by the environment in which modern aircraft operate, the nature of the structure of the airframe, the way they are painted and the way in which they are used. As a consequence of all this, the paints which have been formulated for aerospace use usually differ from paint used in other industrial areas. It has often meant using ingredients which are regarded as hazardous either to health, such as chromate pigments, or to the environment, such as large quantities of strong solvents. Bearing this in mind, modern formulations have had to evolve, improving performance and taking into account the results of using hazardous ingredients which might affect users of the coatings, innocent bystanders and the environment. Here we consider the conflict between these influences and show the position reached within the industry.
The Kanigen process of nickel deposition by catalytic chemical reduction is a practical production method for uniformly coating metals and non‐metals with a layer of hard, corrosion‐resistant amorphous nickel‐phosphorus alloy. This process has made available to industry a material with new and considerably improved surface properties. Both the technique and the product are unique. The amorphous high‐nickel low‐phosphorus alloy is deposited at a uniform rate on the piece being coated wherever it is in contact with the hot solution and whatever the shape. The non‐porous coating is hard but relatively brittle, adheres well to most properly pretreated basis materials, and has improved corrosion resistance (compared to pure nickel) which can be increased further by heat treatment.