Alumina Ceramic Foam Filter Plate For Aluminum Casting Filtration

1. Material

The filter plate is mainly made of high-purity alumina (Al₂O₃ ≥96%), formed by impregnating organic foam sponge with alumina slurry and high-temperature sintering.

It forms a unique mullite-corundum 3D interconnected open-cell network structure.

Porosity reaches 80–90%.

It features excellent chemical inertness, strong resistance to molten aluminum corrosion, good thermal shock resistance, and stable performance up to 1250°C.

It will not contaminate aluminum melt during casting.

PPI grades available: 10/20/30/40/50/60 PPI for different filtration precision requirements.

2. Dimensions

Standard sizes: 7"×7",  9"×9", 12"×12", 15"×15", 17"×17", 20"×20", 23"×23", 26"×26", square plates.

Thickness commonly 20–50 mm.

Custom rectangular, round or special shapes are acceptable.

Dimensional tolerance is controlled within ±3 mm.

Beveled edge design is optional to match filter box installation.

3. Edge Wrapping (Sealing Gasket)

Edge wrapping is the high-temperature sealing layer bonded to the four sides of the ceramic foam filter plate.

Its core function is to seal the gap between filter plate and filter housing, preventing molten metal bypassing the filter media directly, which would cause unfiltered melt and casting defects.

We supply 3 main types of wrapping options for different casting working conditions:

1. Asbestos Cotton Gasket:

Made of high-alumina ceramic fiber cotton, bonded to the filter perimeter with high-temperature inorganic adhesive. No natural cotton fibre, 100% asbestos-free.

✅Characteristics: Super soft, fluffy and highly compressible. It can fill uneven gaps between filter plate and filter box very well.

✅Great shock-absorbing effect during installation. Working temperature up to 1260°C. Compared with ceramic fiber paper wrapping, fiber cotton has better elasticity and larger compression allowance. It can compensate bigger dimensional tolerance of filter box. It is widely used for manual loading in gravity casting, aluminum ingot and common aluminum alloy casting.

✅Limitation: Lower structural strength than fiber paper and hard fiber board. It is easier to be damaged by strong scouring from fast molten aluminum flow.

✅Not recommended for high-speed continuous casting.

✅Custom thickness available: 3mm /5mm /8mm.

2. Standard Ceramic Fiber Gasket:

Made of high-alumina ceramic fiber paper, bonded with high-temperature inorganic adhesive.

✅Characteristics: General-purpose, cost-effective, soft and compressible, good sealing performance for most gravity casting and low-pressure casting.

✅Working temperature up to 1260°C. Slight compression during installation fills uneven gaps.

✅Widely used for aluminum billet, slab and common automotive aluminum castings.

3. Flexible Vermiculite Gasket:

Vermiculite-based flexible sealing gasket.

✅Characteristics: Excellent expansion performance when heated.

✅Once touching hot melt, it expands slightly to eliminate tiny assembly gaps.

✅Low smoke, low volatile content.

✅Ideal for high-end aerospace and high-purity aluminum casting, avoids carbon contamination. Higher cost than ceramic fiber wrapping.

4. Beveled / Chamfered Wrapping:

✅Custom wrapping with 45° chamfer on the outer edge of the seal.

✅Can be applied on ceramic fiber or vermiculite material.

✅Characteristics: Easy insertion into filter box; prevents tearing of the gasket during installation. Perfect for automated filter loading systems.

General features of all wrapping types:

✅Inorganic composition, no organic residues that release gas at casting temperature.

✅Strong adhesion to alumina filter plate edges; no peeling or dropping into molten aluminum.

✅Resistant to thermal shock, does not crack under rapid temperature change.

✅Custom thickness available: commonly 3mm / 5mm / 8mm.

5. Application

Alumina ceramic foam filter plates are specially designed for molten metal purification in non-ferrous metal foundries, mainly for aluminum and aluminum alloy melt treatment.

✅ Casting Processes: Continuous casting, semi-continuous casting, gravity casting, low-pressure casting, high-pressure die casting and investment casting.

✅ End Products:

● Aluminum billet, aluminum slab, aluminum ingot and aluminum foil rolling stock;

● Automotive aluminum parts: wheel hubs, engine blocks, cylinder heads, suspension brackets, transmission housings;

● Aerospace & high-end aluminum components: structural aluminum castings, precision thin-wall parts;

● Aluminum for electronics: heat sinks, battery shell castings, communication equipment parts.

✅ Other Applications: It can also serve for filtration of copper, zinc and magnesium alloy melt, high-temperature gas-solid separation, and catalyst carrier in high-temperature reaction systems.

By removing impurities before melt filling, the filter plate stabilizes casting quality, reduces scrap rate and improves mechanical properties of final castings.

6. Filtration Performance

The filter relies on a combined mechanism of surface interception, deep-bed adsorption and flow rectification.

✅ Surface interception: Large-size slag inclusions, oxide films and refractory debris are trapped on the inlet surface of the filter plate.

✅ Deep-bed adsorption: The 3D interconnected pore network captures micron-scale fine non-metallic inclusions inside the pores. Fine alumina, silica and spinel inclusions are adsorbed and retained by the ceramic pore walls.

✅ Flow rectification: Turbulent molten aluminum is converted into stable laminar flow. This suppresses vortex flow and reduces air entrainment and secondary oxide formation during filling.

Filtration effect by PPI grade:

● Low PPI (10/20 PPI): Larger pore size, high melt flow rate, for coarse slag removal; suitable for large-volume billet/slab casting.

● Medium PPI (30/40 PPI): Balanced flow rate and precision, most widely used for automotive aluminum castings.

● High PPI (50/60 PPI): Fine pores, high filtration accuracy, captures micro inclusions; for aerospace, thin-wall and high-purity aluminum castings, lower melt throughput.

Quality benefits after filtration:

● Reduce casting defects: oxide inclusions, pinholes, blisters, cracks and cold shuts;

● Improve mechanical performance: higher tensile strength, elongation and fatigue resistance;

● Better surface finish and machining performance, less tool wear during CNC machining;

● Lower scrap rate and fewer rejected parts in non-destructive testing (X-ray inspection).

Advantages of Hebei CangChen-ACFFP

✅ Hebei CangChen is a professional manufacturer and exporter of alumina ceramic foam filter plates. We maintain strict quality control for raw materials and finished products.

✅ We supply full standard sizes and support fast custom production for special shapes, PPI and multiple edge wrapping types (ceramic fiber, rigid fiber board, vermiculite, chamfered wrapping) with customizable thickness. ✅ Our products have stable thermal shock resistance and consistent filtration performance, low breakage rate during casting. We hold REACH & RoHS compliance certificates, with rich export experience for global foundry customers.

✅ Flexible packaging and reliable logistics are available to meet DAP / DDP trade terms.