Ceramic media and abrasives include aluminum oxide, boron carbide, cubic boron nitride (CBN), cerium oxide, fabricated diamond, silicate, silicon carbide, tin oxide, tungsten carbide, zirconia, and other fused or sintered crystalline inorganic materials. These materials are very dense, and provide outstanding grinding and finishing performance on many different workpiece materials. Most ceramic abrasives and media are used in applications such as abrasive jet cutting, blasting, blending, burnishing, cleaning and surface preparation, and intermediate cutting. Ceramic abrasives and ceramic media are also used in deburring and deflashing, descaling and stripping, fast cutting and aggressive material removal, grinding and ball milling, peening, polishing and lapping, and tumbling and mass finishing.

Selection Criteria

Selecting ceramic abrasives and media requires an analysis of type, shape, media size, and grit grade or shot size. There are two choices for type: abrasive grain or grit, and finishing or shaped media. Many different types of shapes are available:

• Balls
• Ball cones
• Cones
• Crushed or irregular particles
• Cubes
• Cylinders
• Diagonals
• Ovals
• Pyramids
• Stars
• Triangles
• Wedges

Media sizes for ceramic abrasives and media are specified by dimension A or dimension B. There are several grit grades and shot sizes. Choices include:

• ANSI bonded
• ANSI or CAMI coated
• FEPA F
• FEPA P
• JIS
• Mesh-graded
• Micron-graded
• SAE

ANSI grading systems are used in the United States, while FEPA grading systems are used in Europe. JIS is an acronym for Japanese Industrial Standard.

Materials

Ceramic abrasives and media are made of many different materials. They include:

• Aluminum oxide
• Alumina-zirconia
• Boron carbide
• Cerium oxide
• Chromium oxide
• Porcelain

Aluminum oxide is a common industrial mineral. Alumina-zirconia abrasive grains consist of a fused alloy of aluminum oxide and zirconium oxide. Boron carbide is a very hard abrasive often used to make sticks for dressing other softer abrasives. Cerium oxide, a softer abrasive, is used for polishing and planarization applications. Ceramic abrasives and media with chromium oxide have a small crystal structure and high hardness. Traditional porcelain is made from a mixture of feldspar, clay (koalin) and flint.

Types of ceramic abrasives and media include:

• Silica and silicates
• Silicon carbide
• Sol-gel
• Superabrasives
• Tin oxide
• Tungsten oxide
• Zirconia

Silica and silicate materials include fused silica, quartz, koalin or clay based materials, cordierite, steatite, forsterite, sillimanite, zircon, porcelain, and fireclay. Silicon carbide is harder than aluminum oxide, but more friable than fused aluminum oxide grains. Sol-gel ceramic abrasives typically consist of aluminum oxide with or without additional modifiers produced using a sol-gel and sintering process. Superabrasives include cubic boron nitride (CBN). Tin oxide is a safe abrasive used for polishing glass. Ceramic abrasives and media with crushed tungsten carbide grits or zirconia are also commonly available.

Image credits:

SpeedFam Corporation | Advanced Abrasives Corp.