Applications of Syalons
As modern industry continues to demand stronger, harder, more wear resistant and heat resistant materials, which will operate cost effectively in hostile environments, it has become essential to seek alternative engineering materials.
The discovery of silicon nitride in 1857 by Deville and Whaler caused no excitement among the engineering fraternity of the day. Yet the announcement more than a century later, in 1972, that an alloy of this same material had been found stimulated enormous interest and triggered off investigations on a worldwide scale. The reasons why the two events were heralded in such dissimilar ways gives us an insight into the developments that have taken place in our major industries.
Modern industry requires stronger, harder, more wear resistant and heat resistant materials, which will operate cost effectively in more hostile environments than ever before. Today's aircraft engines require increasing thrust to weight ratios, which is generally achieved by both weight reduction and increased turbine inlet temperatures. The required operating temperatures of modern jet engines exceed the temperature limitations imposed by metallic turbine components. It has therefore become essential to seek alternative engineering materials.
In metal forming, escalating labour and capital costs mean that forming dies and rollers have to produce higher tonnages to greater tolerances than before. In extrusion and drawing operations for example, surface finish and metallurgical properties, combined with the need for highly toleranced often means that traditional die materials are no longer effective.
Wear resistance and resistance to chemical attack are of prime importance for today's high–technology materials. Power stations, which burn powdered fuel, suffer severely from burner tip erosion. Coal dewatering plants require highly abrasive resistant materials for their filtration systems and super hard nitride ceramics are replacing the more traditional tungsten carbide in many of these applications.
Restrictions on emissions for automotive engines and higher fuel costs have stimulated an interest in the use of super–hard light–weight inert materials in the automotive industry; in fact ceramics have become accepted in most industries.
From Silicon Nitride to Sialon
It became apparent in the 1960s and early 1970s that silicon nitride had some remarkable engineering properties. It exhibited good thermal shock, high strengths could be achieved, the material was oxidation resistant and thermodynamically stable. This material was an obvious candidate for the arduous applications in modern industry.
Unfortunately, silicon nitride did not lend itself to ease of fabrication. The best properties were only obtained from hot–pressed material, thus shapes could only be produced at extremely high cost by diamond grinding and even this material had relatively poor high temperature properties.
The discovery of an alloy of silicon nitride made independently in the UK by Jack and Wilson, and in Japan by Osama et al, brought the advantages of a material based upon silicon nitride, which was sinterable. Complex shapes could now be produced by conventional ceramics forming processes and then fired to high density products. These alloys, based upon silicon nitride, are known as sialons.
The current generation of sialons produced by International Syalons (Newcastle) Limited are extremely sophisticated ceramics: they have grown through research and development from patents granted in the early 1970s into a product range which has outstanding engineering properties.
What are Sialons?
Here the term sialon is reserved for the aluminium–silicon–oxyniride alloys of silicon nitride, which have been sintered into hard, high strength materials using yttrium oxide as a sintering aid. Read more here...
Industrial Wear Applications
Syalon 101 and Syalon 050 are characterised by excellent mechanical strength and hardness, making them ideal candidates for many extreme industrial wear applications. Read more here...
Molten Metal Handling Applications
Syalon 101 is world renowned for its exceptional performance in non-ferrous molten metal handling applications, particularly aluminium and its alloys. Increasing use is now also being found in the handling of molten copper and zinc. Read more here...
Metal Forming Applications
Metal forming applications such as welding, extrusion and cutting can all benefit from Syalon 101s and Syalon 050s excellent mechanical and thermal properties and chemical stability. Read more here...
Oil & Gas Applications
As existing supplies of oil and gas are depleted, these industries are being forced to explore ever more severe environments for future supplies. To help this exploration, Oil and Gas companies are utilising the excellent characteristics of Syalons, such as corrosion and erosion resistance, heat tolerance and light weight, to replace traditional metal components. Read more here...
Chemical & Process Industry Applications
The chemical and process industries are continually seeking new advanced materials to help extend the life of critical components. Syalon ceramics are at the forefront of this search. Read more here...