Zirconia Foam

Based on zirconia, zirconia foam is a kind of special porous ceramics with the characteristics of good mechanical properties, strong thermal and corrosion resistance, chemical inertness, and consistent quality and its heat-resistant temperature is higher than about 1760 °C, with very high strength and excellent high temperature impact. The common methods to make a zirconia foam include organic foam impregnating method, foaming method, add of pore-forming method, sol-gel method.

Alumina ceramic foams are usually manufactured using the polymeric sponge method (Figure 1) ^[1]. This method involves the impregnation of a polyurethane sponge with slurries that are made of Al₂O₃ particles. This is then followed by pyrolysis and sintering to solidify the foam and make it hard.

Basic Parameters

Applications

As with the characteristics of 3D net-work structure, high porosity, excellent chemical and thermal resistance, zirconia foam is commonly used as filters in filtration of stainless steel, carbon steel and large castings of molten metal, etc. With the excellent resistance to attack and corrosion from molten steel liquid, zirconia foam filters can effectively remove inclusions, reduce trapped gas from liquid metal and provide laminar flow, and then the filtered metal is significantly cleaner. Cleaner metal results in higher-quality castings, less scrap, and fewer inclusion defects.

• Metal Types

It is physically stable and can resist very high temperature (with max. service temperature up to about 1700℃), thereby making it a good filtering device for molten all types of steel, such as unalloyed, low alloyed, stainless, and high-alloyed as well as nickel and cobalt-based super-alloys.

• Properties of Zirconia Foam Filter

• It is porous and the degree of porosity varies as per the filtering requirements.
• Bending and compressive strength of the filter is high because of which it can be fitted to various channels used for the flow of molten metals.
• The bulk density of the Zirconia is nearly constant whereas the pores density can be varied as per industry requirements.
• It is resistant to atmospheric oxygen which facilitates easy storage of the material.

• Transmittance of Zirconia Foam Filter

Transmittance refers to the effective filtration area of the foam ceramic filter plate product. The higher the light transmittance, the less blind holes are, and the more effective the filter holes (potholes), the better the filtering effect. The transmittance of the filter plate is specified to be 95% or more

Alfa Chemistry offers zirconia foam filters in all standard dimensions and different thicknesses. Custom-made cut-to-size filters are also possible. To place an order or request a quote, please don't hesitate to contact us.