Diamond segments or rims are made up of a mixture of diamonds and metal powders. Diamonds used in blades are almost exclusively manufactured diamonds in various grit size and quality grades.
In the manufacturing process, the metal powder and diamond grit mixture is hot pressed at high temperatures to form a solid metal alloy (called the bond or matrix) in which the diamond grit is retained.
The segment or rim is slightly wider than the blade core. This allows the cutting edge to penetrate through the material while protecting the steel body.
The application of bond (or Matrix)
- Typically the following rule applies :
- For hard materials : use soft bonds.
- For soft materials : use hard bonds.
Example :
Limestone is soft and abrasive therefore we would use a hard bonded blade. Reinforced concrete with river pebble aggregate is hard therefore we would use a soft bonded blade.
Hard Bond
Means that the compilation of metals when sintered together forms a segment of approximately 105 to 120 HRB (hardness) and is very resistant to the soft abrasive materials being sawn, thus releasing diamond at the appropriate rate.
Hard bonds typically consist of the following metal powders – cobalt, iron, tungsten carbide and are grey to dark grey in colour.
Soft Bond
Means that the compilation of metals when sintered together forms a segment of approximately 90 to 105 HRB (hardness) and allows the segment to wear quicker thus retaining diamond on the cutting surface.
Soft bonds typically consist of the following metal powders - copper, bronze and cobalt, and are generally bronze to light silver in colour.

                                               How Do Diamond Blades Work?
Understanding how a diamond blade works will help you choose a blade with the right characteristics and cutting quality for your needs. Here are the four basic blade components:

• The metal core, a precision-engineered steel disk with a segmented rim that holds the diamonds.
• The synthetic diamond crystals, the sharp cutting teeth that slice through the concrete.
• The matrix, a metal bond that holds the diamond particles in place until they wear away.
• The weld, which attaches the cutting segments to the core (most segments are laser welded or soldered).
  The exposed diamonds on the surface of each segment do the cutting, using abrasive action to slice through material as the blade rotates at high speeds. As the diamonds at the surface become dull through use, the matrix begins to shed away to release the worn diamond crystals and expose new, sharp diamonds embedded within the matrix.

The most important fact to know is that the hardness of the matrix controls how quickly a blade wears.

Here's the basic rule: A diamond blade used to cut soft, abrasive materials (such as uncured, green concrete) should have a hard metal bond so the exposed diamonds are fully utilized before they shed away. Conversely, a blade for cutting hard, nonabrasive concrete should have a soft bond to allow for easier erosion of the matrix, which will ensure exposure of new, sharp diamonds when you need them.