October 12th, 2020
Abrasive machining, precision grinding, super-finishing: these are all critical processes that leverage high-performance ceramics to achieve the desired end-result. Though the means differ dramatically, each one concerns the targeted removal of material from objects via the action of ceramic abrasive particles.
Saint-Gobain Abrasive Grains has been at the forefront of engineering ceramics for abrasive processes for well over a century. We have persistently driven material and technical ingenuity to generate value-added abrasive grains based on precision grain chemistries and finely-tuned structural properties.
This article will serve as a brief introduction to some common ceramic abrasive chemistries, while also providing some insight into the unique expertise of Saint-Gobain Abrasive Grains.
Alumina Ceramic Abrasives
Aluminum oxide, commonly abbreviated to alumina (Al2O3), is an extremely tough ceramic typically graded by purity. It can be obtained in decent purities from bauxite ore via high-temperature electrofusion, yielding blocky crystals known as brown fused alumina (BFA).
Sintering pure grade Bayer alumina provides greater control over grain chemistry thus enhanced performance characteristics, such as improved friability. This is known as white fused alumina (WFA), and it is the golden standard aluminum oxide grain for bonded abrasives.
Calcined alumina is a third form of aluminum oxide, which is extremely high purity and characterised by optimal particle size characteristics. It is engineered by heating alumina powders to temperatures exceeding 1000°C, then milling them to produce a fine powder composed of highly uniform crystals. This type of ceramic abrasive is typically confined to precision lapping and polishing processes.
Silica-Based Ceramic Abrasives
Silicon carbide (SiC) is a well-established non-oxide technical ceramic that is routinely used for abrasive applications. It can be produced via a myriad different sintering techniques, and though these yield a strong grain with good tribological properties, material defects are common.
Zirconia Ceramic Abrasives
Zirconium dioxide, also abbreviated to zirconia (ZrO2), is another high-performance oxide ceramic characterised by outstanding hardness and fracture toughness. In fact, zirconia ceramic abrasives have practically unprecedented resistance to crack propagation – but they are prone to temperature-dependent phase transitions, which can render them unsuitable for many machining applications.
A solution to this issue is to fuse alumina particles with zircon sand at high temperatures, yielding a fine primary alumina-zirconia crystal structure with superior thermomechanical and chemical characteristics. This produces an anti-friable ceramic grain with outstanding wear-resistant properties. Alumina-zirconia alloys are subsequently among the most durable ceramic abrasive grains on the market, outperforming commodity BFA and WFA on multiple fronts.
Ceramic abrasives from Saint-Gobain
At Saint-Gobain Ceramic abrasives, we operate around the three basic pillars of ceramic grain performance: Microstructure, macrostructure, and chemistry. Control all three of these elements precisely, and you can reliably generate high-performance fused grains with spectacular cutting capabilities.