TWI Industrial Member Report Summary 777/2003
P Jackson, A Taylor and C-M Lee
Corrosion of a metal component frequently causes a reduction in performance. There are a number of coating corrosion protection methods available but these are invariably coloured and change the appearance of the underlying substrate. Although they can provide the required protection, they are unsuitable for many applications such as jewellery, ironmongery and cutlery.
Sol-gel derived coatings are frequently both transparent and thin and also provide modifications to surface properties. They are based on the development of a highly homogeneous silica-based network that contains an organic-inorganic hybrid molecule such as a silane. This solution can be subsequently deposited on to a substrate and the solvent evaporated off to yield the coating, which is heated to cure.
This project was aimed at establishing a sol-gel methodology which yields coatings with improved corrosion protection compared to the parent metal substrate. The effectiveness of various compositions and processing parameters was also investigated.
- Evaluate the corrosion protection of sol-gel based coatings on a variety of substrates in the environments of sodium chloride, ferric chloride and hydrogen sulphide.
- Quantify the effect of fluorine based silane additives on the corrosion performance of silica based coatings deposited on stainless steel, aluminium and brass.