Increased fracture toughness
Design engineered to provide cushioning from impact
Ceramic Tile Cracking/Breakage
Tile cracking leads to tile loss and may lead to premature failure of the ceramic lagging, with a number of causes leading to this issue:
- Lagging design that has the ceramic tiles butted up against one another can result in cracking from impact between the tiles when subjected to shock loads, which can occur when material becomes caught between the conveyor belt and the ceramic lagging (see photos adjacent).
- Poor quality aluminium oxide tiles are prone to cracking and breakage/wear of the raised dimples. Eighty percent of the raw material cost of ceramic lagging is the aluminium oxide tiles and this offers the largest potential cost saving for manufacturers of lower cost ceramic lagging. Unfortunately, reducing the quality of the aluminium oxide tiles has a direct impact on the ceramic lagging performance.
- With the increase in aluminium oxide content, the vickers hardness, wear resistance and flex cracking resistance also increase. The tile cost also increases with aluminium oxide content (refer Table#2 below).
TABLE#2 – AI203 properties
|Vickers Hardness||(Hv 10)||600-800||1000-1100||1200-1300|
|Impact Resistance||(MPa m1/2)||2.5||3.3||4.1|
|20x20x5 Tile Cost||($US/pc)||$0.03||$0.06||$0.09|
The unique design of Elastotec Hot Vulcanised Ceramic Lagging (HVCL) and Cold Vulcanised Ceramic Lagging (CVCL) ensures that tiles are bonded with rubber on both sides and back, providing a more reliable layer of protection from impact and significantly reducing the risk of tile cracking.
An additional benefit of the lagging design is the increased area for bonding between the tile and the rubber. For typical 20 x 20mm-sized ceramic tiles used by many ceramic lagging manufacturers the bonding areas are:
Tile bonding back only 400 mm2/tile
Tile bonding back and sides 720 mm2/tile
This is an 80% increase in bonding area, resulting in increased force required to pull the tiles from the rubber.
Aluminium Oxide Tile Quality
The key properties of ceramic tiles in terms of performance of ceramic lagging include vickers hardness, impact resistance and abrasion resistance. These properties are specified and checked for each production batch of tiles to ensure a consistent performance. Table#2 lists the properties of the 96% aluminium oxide tiles used in HVCL, with the 96% aluminium oxide tiles demonstrating high hardness and impact resistance, resulting in increased levels of abrasion resistance and longer life than obtained with lower grades.