Effect of Elements in Carcass Adhesive of Diamond Saw Blade

The abrasion resistance of the carcass must match the abrasion resistance of the diamond and the material being processed. However, how to select the composition of the metal carcass and what is the function of the elements in the carcass binder? Here are some information for your reference.

 

I. Role of Copper(Cu) in Adhesives
Copper and copper-based alloys are the most widely used metal binders in diamond tools, and electrolytic copper powder is the most widely used metal. Copper and copper-based alloys have low sintering temperature, good formability and sinterability, and good solubility with other elements. Although copper hardly wets diamonds, alloys of some elements and copper greatly improve their wettability.

 

Copper alloys, such as one of the copper and carbide-forming elements Cr, Ti, W, V, Fe, can greatly reduce the wetting angle of copper alloys to diamonds. Copper and nickel, cobalt, manganese, tin and zinc can form a variety of solid solutions, which strengthens the matrix metal.

II. The Role of Tin(Sn) in Adhesives
Tin is an element that reduces the surface tension of liquid alloy, has the function of reducing the wetting angle of liquid alloy to diamond, improves the wetting angle of bonding metal to diamond, reduces the melting point of alloy and improves the compaction formability. Sn is widely used in adhesives, but its use is limited due to its large expansion coefficient.

III. Function of Zinc(Zn) in Adhesives
In diamond tools, Zn and Sn have many similarities, such as low melting point and good deformation, and Zn is not as good as Sn in changing wettability of diamond. The vapor pressure of metallic zinc is very high and it is easy to gasify, so the amount of zinc should be paid attention to when using it.

IV. Role of Aluminum(Ai) in Adhesives
Aluminum metal is a light metal with excellent properties and a good deoxidant. The wetting angle of Al on diamond is 75 degrees at 800 degrees C and 10 degrees at 1000 degrees C. Adding aluminium powder to the binder of diamond tools forms carbide Ti3AlC and intermetallic compound TiAl in the matrix alloy.

V. Role of Iron(Fe) in Adhesives
Iron plays a dual role in the bonding agent. One is to form cementite carbide with diamond, the other is to alloy with other elements to strengthen the carcass. Iron and diamond have better wettability than copper and aluminium, and iron and diamond have higher adhesion than cobalt. Additionally, dissolving appropriate amount of carbon in Fe-based alloys facilitates its bonding with diamond, i.e. proper etching of diamond in Fe-based alloys increases the bonding force between bonding agent and diamond. In practical production, diamond is generally not exposed smoothly on the saw blade fracture, but is covered by a layer of alloy, which is the expression of bonding strength enhancement.

VI. Role of Cobalt(Co) in Binders
Co and Fe are transitional elements with similar characteristics. Co can form carbide Co2C with diamond under certain conditions and coat diamond with very thin cobalt film. In this way, Co can not only reduce the internal interfacial tension with diamond, but also have a great adhesion to diamond in liquid phase, so Co is an excellent bonding material.

VII. Role of Nickel(Ni) in Adhesives
Nickel is a face-centered cubic structure with good ductility, toughness and oxidation resistance. It can be infinitely soluble with copper. Nickel is an austenitizing element and can be expanded. α In phase region, it is difficult to react with C. The reaction with the inner interface of diamond hardly occurs during high temperature sintering. But liquid Ni can adhere firmly to the surface of carbon fibers, forming a very thin film.

Among the binders for diamond tools, Ni is an indispensable element. In Cu-based alloys, Ni can be infinitely soluble with Cu, which can strengthen carcass alloying, inhibit loss of low melting point metals, increase toughness and wear resistance. Adding Ni and Cu into Fe-based alloy can reduce sintering temperature, reduce thermal corrosion of bonding metal to diamond, and select proper proportion of Fe and Ni to increase the holding power of Fe-based adhesive to diamond greatly.

VIII. Role of Manganese(Mn) in Adhesives
Manganese is similar to iron in metal binder, but it has strong penetration and deoxidization ability and is easy to oxidize. Generally, the amount of Mn added is not high, which can deoxidize and strengthen the carcass.

Ⅸ. Role of Chromium(Cr) in Adhesives
Metallic chromium is a strong carbide-forming element. In the carcass of the diamond trough saw blade, chromium can act as a silencer because it is related to the activation energy of CR. Adding a small amount of Cr into the Cu-based matrix can reduce the wetting angle of copper-based alloy to diamond and improve the bonding strength of copper-based alloy to diamond.

X. Role of Titanium(Ti) in Adhesives
Titanium is a strong carbide-forming element which is easy to oxidize and difficult to reduce. Ti preferentially generates TiO without TiC in the presence of oxygen. Titanium metal is a good structural material with low strength reduction at high temperature, high heat resistance, corrosion resistance and melting point. Relevant studies have shown that adding proper amount of titanium into the matrix of diamond saw blade is beneficial to improving the service life of the saw blade.

XI. Role of Tungsten(W) in Adhesives
Tungsten is a strong carbide-forming element and can be used as a framework material. A certain amount of tungsten powder is deposited on the diamond surface. After sintering, WC, WCoV and WCoC are generated on the diamond surface. Tungsten and other bonded metals such as Cu, Co, Ni, Fe have good compatibility.

XII. Role of Rare Earth Elements in Adhesives
Rare earth elements can effectively reduce the melting point of the alloy. La and Ce have strong deoxidization, desulfurization and ammonia removal functions, and can inhibit the segregation of impurities such as oxides, sulfides and nitrides at the interface. It can improve the bending strength of the material. In high Co or pure Co matrix, the addition of rare earth Ce is beneficial to improve the mechanical properties of the matrix, and a small amount of Ce can play a good role in bronze matrix matrix matrix (about 0.12wt%).

XIII. Behavior of Silicon(Si) in Binder for Diamond Tools
The linear expansion coefficient of silicon is close to that of diamond and lower than that of other metals. Volume effects during heating and cooling are small. Good compatibility between silicon and diamond; Silicon reduces the melting point of the alloy and has a strong deoxidizing capacity.