Surface engineering projects

New projects

PR13794: Improved corrosion and wear resistant coatings by cold spray

Start date January 2009
Cost per sponsor £20,000 (one payment)
Contact D Harvey
Cold spray coating technology has been developed with the objective of improving the surface performance of components across a wide range of industry sectors in order to meet the needs of challenging environments, to increase operational reliability and availability, or simply to extend component life whilst reducing substrate materials and life cycle costs. Unlike thermal spraying processes, which produce coatings with properties inferior to the equivalent parent material due to in-flight spray particle oxidation and re-melting, the new technology of cold spray produces coatings with properties much closer to those of parent material. Very few property data exist, but initial studies claim cold spray coatings can provide superior corrosion and wear resistance, and have sufficient mechanical strength in the as-deposited condition that the process can be used for spray-forming or additive manufacturing and restoration of component dimensions. The objective of this project is to address the current lack of cold spray property data, to validate these claims and to define applications where cold spray offers the greatest technical and economic benefits.

Completed projects

Thermally sprayed aluminium alloys for the prevention of corrosion and environmentally assisted cracking of welded corrosion resistant alloys

Buy back fee £50 000
Completion date September 2008
Contact D Harvey
Welded corrosion resistant alloys (CRAs) are subject to localised corrosion or environmentally assisted cracking (EAC) in chloride-containing natural environments. The viability of thermally sprayed aluminium (TSA) is important for provision of long-term integrity through mitigation of such degradation and avoidance of containment loss and thus, associated plant safety and environmental risks. This project will evaluate the protection of CRA welds by TSA via corrosion tests related to immersed service (e.g. controlled potential alloys and internal protection of pipeline welds during commissioning) and topside duty (e.g. corrosion under insulation and external protection of welded field joints).

14661: Thermally sprayed aluminium coatings for prevention of corrosion of duplex stainless steels at elevated temperature

Buy back fee £40 000
Completion date May 2005
Contact D Harvey
There are increasing concerns regarding external chloride stress corrosion cracking (SCC) of duplex stainless steels on topsides, and crevice/pitting corrosion of umbilicals and immersed facilities, at elevated temperatures up to 150°C. Furthermore, there are doubts regarding the reliability of organic coatings at this temperature, and it is known that under certain conditions cathodic protection (CP) has led to hydrogen embrittlement induced component failure. To address these issues, this project evaluated the suitability of thermally sprayed aluminium (TSA) coatings on duplex stainless steel for prevention of SCC and crevice/pitting corrosion allowing provision of key recommendations for successful specification.

13458: Improving the reliability and cost performance of thermally sprayed aluminium coatings

Buy back fee £28 000
Completion date April 2003
Contact D Harvey
Thermally sprayed aluminium (TSA) coatings are widely specified for protection of steel structures and components against saline aqueous corrosion, but there is increasing industrial requirement to extend its application to very severe environments including deep water, and to reduce the cost for existing applications. The objective of the project is to develop improved TSA coatings through evaluation and validation of recently developed thermal spray equipment and sealant compositions. Benefits will include improved coatings, reduced application and maintenance costs, and a reduction in the operator exposure to respirable fume and the risk of fire or explosion from residual fine metal dust.

13946: Validation of KERONITE® - A novel coating for light metal alloys

Buy back fee £15 000
Completion date January 03
Contact D Harvey
KERONITE® is a new surface treatment for aluminium, magnesium, titanium and other light metal alloys that transforms the metal surface to a hard and dense ceramic layer. The process offers an environmentally friendly coating method for enhancing the wear, tribology and corrosion properties of a component surface, including access to restricted surfaces, whilst retaining initial component dimensions. This project demonstrated the application of novel KERONITE® coatings to components selected from industries including aerospace and automotive and validated improved surface performance compared to conventional hard anodised and chrome plated coatings.

12514: Metal ceramic graded composite coatings by HVOF spraying for improved protection in corrosive environments

Buy back fee £30 000
Completion date October 2002
Contact D Harvey
The high velocity oxy-fuel (HVOF) spraying process allows for the deposition of very low porosity, high quality coatings of ceramic and graded ceramic-metal materials. Because of their chemical stability and high hardness these coatings are attractive candidates for the protection, or repair, of components that experience high temperature corrosive environments, often with wear occurring. The aim of this project was be to determine how coating structures can be prepared by HVOF spraying that give optimum protection in realistic corrosive environments, and to measure both corrosion performance and coating costs.

13309: New processes for wear and corrosion resistant coatings for internal cladding of small bore components

Buy back fee £15 000
Completion date April 02
Contact D Harvey
Damage by wear and corrosion is a major factor determining the life of components such as pumps, valves and tubular sections used in the extraction and transportation of petroleum, gas and related products. In particular, current surface engineering solutions are unable to provide adequate coatings on the internal surfaces of small-bore components. This Group Sponsored Project investigated the production and evaluation of coatings on the internal surfaces of tubular components (50-150mm internal diameter) using laser powder surfacing, rotational arc spraying and laser fusion of rotational arc spray coatings.

5676: Improved corrosion resistant coatings by HVOF spraying.

Buy back fee £28 000
Completion date September 1998
Contact D Harvey
HVOF spraying offers a lower cost alternative to weld overlays for the deposition of corrosion resistant metallic coatings. A cost study has estimated potential savings of 25% to 60% over conventional processes. The aim of this project was to identify the most cost-effective routes to reliable corrosion protection for four coating materials using HVOF.

Surface Engineering at TWI

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